1- The far north
2- The North (Chicago, Niagara Falls)
3- The central belt (New York, Washington)
4- The southern belt
5- Gulf of Mexico and Florida (Miami)

If the Western United States are occupied mostly by mountains and plateaus, with vast arid and desert areas, the central-eastern part is mostly flat or covered by hills and low mountains, and its climate is generally more humid and rainy. Given the vastness of the territory, the climatic differences are remarkable here as well.
Clashes of air masses are large and frequent, making the climate unstable in most of the territory, also with violent phenomena (storms, hail, blizzards, tornadoes). Cold air masses coming from Canada are cold and dry (but pick up moisture when passing over the Great Lakes), those from the Gulf of Mexico are warm and moist.
We divided the territory into four bands, substantially parallel, and within each of them the climate is fairly uniform, although the westernmost part, that of the Great Plains, experiences higher temperature jumps, and is also less humid and rainy than the eastern part, especially in winter.

In this northernmost part (which includes the northernmost part of Montana, North Dakota, Minnesota, Wisconsin, Michigan, the north-east of the state of New York, and northern Vermont, New Hampshire and Maine), the climate is continental with long, cold, and snowy winters, and moderately warm summers. The average daily temperature in January is several degrees below freezing, from 5 °F to 23 °F, while in July it doesn't reach 68 °F. Summer is a fairly rainy season, because of afternoon thunderstorms in the west, and also for the passages of weather disturbances in the area of the Great Lakes and in the east; however, the amount of sunshine is good. During summer, intense heat waves can occur, with peaks above 95 °F, but they last a few days.
Here are the average temperatures of Duluth (Minnesota).
Average temperatures - Duluth
Min (°F)171830415055544636217
Max (°F)192534506372777564523623

In Duluth, precipitation amounts to 30 inches per year, with a winter minimum, when there are frequent but generally not abundant snowfalls, and a summer maximum. Here is the average precipitation.
Average precipitation - Duluth
Prec. (in)10.81.623.

At Duluth, Lake Superior approaches the freezing point in winter (but during colder winters, a thick layer of ice forms), while in summer, although it warms considerably, stays very cool, if not cold, for swimming.
Lake temperature - Duluth
Lake (°F)373636363741506157464139

In this area, precipitation is fairly scarce in the western part, where less than 20 inches per year fall, mainly because of the relatively dry winter, while it becomes more abundant in the Great Lakes region and in the north-east. As a consequence, snowfalls (which typically occur from late October to mid-April) are relatively less abundant in the west, where they amount to about 27 inches per year in North Dakota, while they are definitely abundant around the Great Lakes and in the north-east: typically they range from 60 to 100 inches, but even more than 120 inches in the Upper Peninsula. In the area of the Great Lakes, winter snowfalls are more abundant along the coasts exposed to the north and west (due to a phenomenon called lake-effect snow: cold winds, initially dry, pick up moisture moving across the lakes and bring snowfall on the leeward shores). In Houghton, northern Michigan, on the shores of Lake Superior, 155 in of snow per year fall; in L'Anse, a little more to the south and 1,600 feet above sea level, snowfall amounts to almost 240 inches, or 20 feet per year!
In the Northeast, Mount Washington, in New Hampshire, 6,288 feet high, is constantly affected by disturbances generated by clashes of warm and cold air masses, and receives no less than 275 inches (23 feet) of snow per year.

Lake Placid

Being the climate of this area inhospitable, no large cities are found.

In this band (which in the southern part extends to the north of Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, Connecticut and Massachusetts), the climate is continental: winter is still cold and snowy, but summer is by now warm or even hot, with averages of July equal to or greater than 68 °F. During summer, afternoon thunderstorms can occur, which are, however, generally less intense and frequent than in the central and southern regions. Winter temperatures are very low: the average in January hovers between 5 °F and 27 °F.
Here too, the western part, that of the Great Plains, is more arid than the central and eastern part.
During winter, cold outbreaks from Canada are accompanied by furious gusts of blizzard, and the temperature can drop to below -22 °F. Snowy landscapes and sub-freezing temperatures even during the day, are the norm for weeks.
Snowfall is more abundant in the Great Lakes area and in the east, where it ranges from 60 to 100 inches per year, while it drops below 40 inches in the westernmost states (Montana, North and South Dakota).
During summer, there may be intense heat waves, with higher temperatures but lower humidity in the west, where it can exceed 105 °F, and more sultry and uncomfortable heat in the Great Lakes and in the east; anyway, they generally last a few days.

In Fargo, North Dakota, the average in January is 9.1 °F, like in the north of Sweden. The temperature drops below 0 °F for fifty days a year on average. Summer is warm: the average in July is 71 °F, although the nights remain typically cool.
Average temperatures - Fargo
Min (°F)051932455559574836195
Max (°F)182336557077828172553723

In Fargo, precipitation amounts to 22.5 inches per year, with a winter minimum and a maximum on early summer, due to afternoon thunderstorms. Snowfall amounts to 50 inches per year. Here is the average precipitation.
Average precipitation - Fargo
Prec. (in)

With an average January temperature of 16 °F, Minneapolis, Minnesota, in winter is colder than Moscow, Russia. In a typical year, from November to April, 50 in of snow fall. In the worst periods, the temperature can drop to -40 °F. On the other hand, summer is hot: the average in July is 73.5 °F. Precipitation, about 30 in, is scarcer in winter and more abundant in summer, when it occurs mainly in the form of thunderstorm.
Further south, in Des Moines (Iowa), the average temperature goes from 22.5 °F in January, to 76 °F in July. On average, 37 inches of snow fall each year.
On the coast of Lake Michigan, Chicago, known as the "Windy City", has a frigid winter, with outbreaks of cold air from the Canadian Arctic region, and humid and hot summers, with thunderstorms in the afternoon, and also with possible heat waves. The average in January is 23.5 °F, but the temperature drops below 0 °F for an average of 6 nights per year. Snowfall amounts to about 40 inches per year. The daily average in July is 74 °F. During summer, the temperature exceeds 89.5 °F for 21 days on average.
Average temperatures - Chicago
Min (°F)161928394859646354433221
Max (°F)303646597081848275634836

In Chicago, 37 in of rain or snow per year fall, with a relative minimum in winter and a summer maximum. Here is the average precipitation.
Average precipitation - Chicago
Prec. (in)

At Chicago, Lake Michigan is very cold in winter, while in summer it's still cool, but becomes almost acceptable for swimming, at least in August, or for those who do not suffer from the cold.
Lake temperature - Chicago
Lake (°F)393737374354667066574841

The climate of cities like Indianapolis (Indiana), Detroit (Michigan) and Cleveland (Ohio), is similar to that of Chicago.
The coast of the state of New York overlooking Lake Erie and Ontario has a similar temperature, but it's particularly snowy, due to the aforementioned lake-effect snow. In Buffalo, nearly 80 inches of snow per year fall. The temperatures are similar to those of Chicago, but summer is a bit less hot, because of the cooling effect of the lake, which here is more evident. The Niagara Falls, a few miles from Buffalo, also belong to this climate zone.
Along the east coast, the average in Portland (Maine), goes from 23 °F in January, to 69 °F in July. The annual precipitation is abundant and amounts to 47 in, well distributed throughout the year (with a relative minimum in summer). Here, 63 in of snow per year fall.

In this band (which includes Kansas, north of Oklahoma, Arkansas and Tennessee, Missouri, the south of Illinois and Indiana, Kentucky, West Virginia, the south of Pennsylvania and New York, New Jersey, Delaware, Massachusetts, Connecticut, Rhode Island, Virginia, District of Columbia), the climate is continental, but is more forgiving in winter, while it becomes quite hot in summer. Winter is still cold, with an average in January ranging from 26.5 °F to 39 °F; there can be waves of cold, but they alternate with mild periods. Summer is hot and sunny, especially in the western part, while it becomes a bit milder in the area of the Appalachian Mountains and along the east coast. Summer is a fairly rainy season too, because of afternoon thunderstorms, but in the central and eastern part, some weather fronts may also pass. In summer, heat waves can occur, even intense, and unlike in the north of the country, they can sometimes be persistent.
(The north-western part of Texas, where lies Amarillo, lies in the highlands, of which we have dealt with in the page about the western United States.)

In this area, several large cities are found.

Kansas City is located in the Great Plains of the Midwest, near the geometric center of the United States; here winter is cold, so that the average in January is 30.5 °F; summer is definitely hot, in fact the average in July is 81 °F, and muggy too. The amount of sunshine is great: 2,800 hours per year. The rainfall amounts to 40 inches per year, and is most abundant in late spring and summer, when it occurs often in the form of thunderstorm. On average, 20 in of snow per year fall.
Further east, the climate of St. Louis (Missouri) and Cincinnati (Ohio) is similar to that of Kansas City.
Average temperatures - Cincinnati
Min (°F)232532435261646355433427
Max (°F)414555667582868679685543

Here is the average precipitation in Cincinnati.
Average precipitation - Cincinnati
Prec. (in)

The Appalachian Mountains are very snowy in winter, at least on the north-western slopes: snowfall is abundant especially on the north-facing hills of West Virginia, when it amounts to about 60 inches per year, and less abundant on those of Virginia, when it amounts to 20 inches per year, while the altitude temper a bit the summer heat in the cities located on the hills.

On the east coast, the proximity to the sea makes the climate a bit more temperate, but it must be said that the prevailing currents come from inland, so the climate is still continental.
New York, despite being on the coast and at a relatively low latitude, of 40° north, has a cold winter: the average in January is 33 °F, while summer is hot and muggy, as the average of July is 76 °F; the climate is perpetually unstable, therefore all kinds of weather may occur: clear or overcast, windy or calm, cold or warm, even within the same week. In the middle of winter, there can be mild days, Mediterranean-like, with about 60 °F, but the cold wind from the northwest can rapidly lower the temperature, and maybe bring snowfall, in a few hours. On average, 27 in of snow per year fall, from December to March (but sometimes also on early April or late November). Rainfall is abundant: about 47 in each year, well distributed throughout the seasons; in summer they often take place in the form of thunderstorms. Despite this, the amount of sunshine is good. In winter, the city can experience snow storms and waves of frost, with low around 5/15 °F, while in summer, masses of warm, moist air from the Gulf of Mexico can make the heat uncomfortable.
Average temperatures - New York
New YorkJanFebMarAprMayJunJulAugSepOctNovDec
Min (°F)272836455464686861504132
Max (°F)394150617279848275645443

In New York, the sea is very cold in winter, while in summer it is a bit cool, but all in all you can swim in July and August, and those who do not suffer from the cold can try to swim also in September.
Sea temperature - New York
New YorkJanFebMarAprMayJunJulAugSepOctNovDec
Sea (°F)454141455263727368635550

New York
Further to the north-east, Boston (Massachusetts), is a bit colder and more snowy in winter: the average in January is 29.5 °F, the annual amount of snow is 45 in, and snow storms can be even worse than in New York. On the other hand, here summer is a little milder: the average in July is 73.5 °F. The sea is colder, so that in spring sometimes fogs occur, while in summer the sea breezes are often effective in tempering the heat. Here too heat waves may occur in summer, and even here there are frequent thunderstorms in the afternoon, sometimes accompanied by hail.
In fact Boston is at the limit of this climate zone: moving further to the north or inland, we enter in the previous area, the colder zone of the north.

South of New York, Washington, the federal capital, is instead a bit warmer than the Big Apple: the average in January rises to 36 °F, and in July to 80 °F. Waves of frost and snow in winter are still possible, but they are a bit rarer: on average, 16 in of snow per year fall, but big snowfalls and winter storms occur only once every three or four years. Summer is hot and humid, with fewer breaks than in New York and Boston: here an annoying and sticky heat dominates, and it can last for weeks. Fortunately, even here there's no shortage of afternoon thunderstorms, which can break the heat at least for a few hours.

In this belt (which includes southern Oklahoma, north-central Texas, south-central Arkansas, southern Tennessee, and most of Mississippi, Alabama, Georgia and North Carolina), winter is mild, given that the average temperature in January is between 39 °F and 48 °F. However, short waves of frost are possible even at these latitudes. In the north of this band, still 6/8 in of snow per year fall, while in the south, the snowfall average drops to about one inch per year, which means that sometimes it never snows for an entire (or maybe more than one) winter.
Summer, is long, hot and muggy, tropical-like, with afternoon thunderstorms, sometimes intense, especially on the east-central part. Oklahoma and north-central Texas are often oppressively hot, with an annoying combination of moisture and high temperature: highs range between 93 °F and 97 °F, but often reach 105 °F for weeks, and the humidity is quite high, at least for those temperatures. Further east, the temperatures are a bit lower, with maximum temperatures usually around 90/91 °F, but the humidity is even higher. After all, we are at the latitude of northern Africa, but south of this area, instead of the Sahara, there is the Gulf of Mexico, from which warm and moist air masses often arrive.
Rainfall drops below 40 inches per year in the western area (Texas, Oklahoma), while it becomes quite abundant in the central-eastern part, where it reaches about 47/51 inches per year. Spring is a very rainy season, because of the conflict between air masses coming from the north, which are still cold, and subtropical air masses lying in the south. In spring, tornadoes may also occur. October is typically a calmer month, with little rain, after the summer thunderstorms and before the return of autumn and winter rains.
At this latitude, the westernmost part of Texas is part of the Chihuahuan Desert, of which we've talked about in the page about the western United States.
Now, let's see in detail the climate of some cities.
In Dallas, the average temperature goes from 46 °F in January to 86.5 °F in July. In winter, the weather is often mild, with highs about 59/68 °F, alternating with sudden cold waves, usually short, in which the temperature can drop a few degrees below freezing. The winter rains are not abundant, and snowfall is rare: on average, 2.4 in of snow fall each year. Summer is long and sultry, very difficult to bear, with some afternoon thunderstorms. There are as many as 100 days in a year with maximum temperatures above 89.5 °F. The weather is pleasant in spring and autumn, although strong thunderstorms and even tornadoes may sometimes occur in spring, and more rarely in autumn.
Average temperatures - Dallas
Min (°F)363946556472757568574637
Max (°F)576168778491959788796657

In Dallas, the annual precipitation amounts to 36 in. Here is the average precipitation.
Average precipitation - Dallas
Prec. (in)

In Memphis, Tennessee, the average temperature goes between 41 °F in January and 82.5 °F in July. Here, too, winter is mild, but it's possible to see short and intense waves of frost, accompanied by snow; on average, 4.7 in of snow per year fall. Rainfall, much more abundant than in Dallas, amounts to 53.5 inches per year, with a relative minimum between August and October. Thunderstorms are possible throughout the year; in summer they are generally short, while in spring they can be intense, and accompanied by wind gusts.
In Atlanta, Georgia, the slightly higher altitude, about 985 feet, temper a little the summer heat: the average temperature is between 43.5 °F in January and 80 °F in July. Even here the rains are abundant, amounting to 50 inches per year, and are well distributed throughout the year, but being usually intense and short-lived, they do not reduce the sunshine hours by much.
Average temperatures - Atlanta
Min (°F)343745526168727264544537
Max (°F)525764738186908882736454

In this region, which includes the area bordering the Gulf of Mexico, the climate is sub-tropical, and it's warm and humid for many months of the year; winter is very mild, since the averages in January are higher than 48 °F. But even here, in spite of the southern location, sometimes cold spells in winter may occur, though quite rarely; the southern part of Florida is the most sheltered, and is almost always spared from the cold, to the point of having an almost tropical climate.
Here too, the western part is less humid: precipitation drops below 40 in only in south-western Texas, while from eastern Texas to the far east, this whole band is rainy and with plenty of thunderstorms.
The sunshine amount is not exceptional, because in the long summer season, although the sun still prevails, clouds can form in the afternoon, associated with thunderstorms, and even the passage of some tropical low pressure systems must be put into account.
Even in this belt, October, and sometimes November, experience a relative lull in precipitation, with calm and pleasant days (if it is not affected by the last hurricanes of the season).

In Austin and San Antonio (Texas), in winter the weather is usually very mild, but with possible short waves of cold or frost: however, the average in January is around 50 °F, for the rest of the year the temperature is similar to that of Dallas, with an equally hot and humid summer, while spring tornadoes are less frequent, for the greater proximity to the sea.

The south-western tip of Texas, from Corpus Christi to the mexican border, has a semi-arid climate, therefore it's different from the rest of the area, which is very rainy. Here the wettest period is from May to October (with a break in July); the rainiest month is September.

In Houston, which is located about 30 miles away from the sea, the average temperature goes from 52.5 °F in January, to 84.5 °F in July, when highs are around 93/95 °F and the humidity is high. It's no surprise that a city so uncomfortably hot, has been the first in the world to see a widespread distribution of air conditioners.
Average temperatures - Houston
Min (°F)434652596873757570615245
Max (°F)636673798691939590827364

In Houston, rainfall amounts to 50 inches per year, so it's fairly abundant, and well distributed throughout the year. Here is the average precipitation.
Average precipitation - Houston
Prec. (in)

At Houston, the Gulf of Mexico is warm enough for swimming from May to November, and it gets very warm in the summer months. In winter, it is cool but not cold, since it doesn't drop below 66 °F in February.
Sea temperature - Houston
Sea (°F)686668727782848484817572

In New Orleans, Louisiana, the summer temperatures are slightly lower than in Houston, but the omnipresence of water makes the heat even heavier. The rains are definitely abundant: even 62 inches per year.

In peninsular Florida, winter is even milder, and spring-like. In Orlando and Tampa, the January average is around 59/61 °F. The climate is tropical-like from mid-May to September, with heat, humidity and frequent thunderstorms. April and October are hot, but a little drier.
Average temperatures - Orlando
Min (°F)505457636873757573685954
Max (°F)727377828891919190847972

In Orlando, 50 inches of rain per year fall, but already at this latitude you notice the minimum in winter, due to the less frequent weather fronts, and the definite maximum in summer, due to thunderstorms. Here is the average rainfall.
Average precipitation - Orlando
Prec. (in)

But it's the southern part of Florida, that is a true winter refuge for many Americans. In Miami, on the southern tip of the state and near the Tropic of Cancer, the January average is 68 °F, therefore here there is no winter: the sun often shines, the air is pleasantly warm, and a nice breeze blows from the sea. Very different, however, is the climate in the long hot summer, which is still sunny, but rainy as well, with frequent thunderstorms, at times strong. The rainiest period goes from May to mid-October. The heat is sweltering, even though the annoyance is partially reduced by the breeze. Winter is instead quite dry, however, there are still 5/6 days with rain per month.
Average temperatures - Miami
Min (°F)575961667073757575726459
Max (°F)757781828688909088848177

In Miami, the sea is warm enough for swimming all year round, since the water temperature in winter is 75 °F; in summer, the sea is very warm for many months.
Sea temperature - Miami
Sea (°F)757575778184848684827977


Between late summer and early autumn, the coasts of the Gulf of Mexico and the southern Atlantic states (Georgia, North and South Carolina) can be affected by tropical depressions and hurricanes, which occasionally can also affect other Atlantic coastal states. The hurricane season runs from June to November, although they are most likely from mid-August to late September.

Another danger comes from tornadoes, large and dangerous whirlwinds, which are very rare in the western part of the United States (the states of the Pacific and the Rocky Mountains, see the page of the Western United States), and are typical of the central and eastern states we are dealing with here, except the northern portions of the states of the Great Lakes and of the northeast. However, tornadoes are more frequent in the south-central band (zones 3 and 4), except on the coast. They develop mainly along two lines: the "Tornado Alley", from South Dakota to northern Texas (north/south direction), and the "Dixie Alley", from Oklahoma to Ohio (south-west/north-east direction).
The months in which they are most frequent are from May and June, but they may also occur between February and April, especially in the south, while in summer they can occur in the northern part of the Great Plains.
In Florida, tornadoes are quite frequent, but they are generally less intense than on the mainland.

See also:
United States West
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