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Average weather, temperature, rainfall, sunshine hours
The climate of Washington, D.C. (
District of Columbia), the US federal capital, is
semi-continental, with cold winters and hot and muggy summers.
The city is located on the 38th parallel, in a way, halfway between the cold and the warm part of the United States. In winter, it can be affected by cold air masses coming from Canada, but less frequently than New York. In summer, there are long periods of sunshine and hot weather, but also beneficial thunderstorms in the afternoon or in the evening which are able to relieve the heat of the day.
The
average temperature ranges from about 3 °C (37.5 °F) in January to about 27 °C (80.5 °F) in July.
Precipitation in Washington is quite abundant, since it amounts to 1,060 millimeters (41.7 inches) per year, and it's evenly spread over the seasons. In summer, the rains mainly occur in the form of afternoon or evening thunderstorms, however, some weather fronts may still pass, able to bring some rainy days.
Winter, from December to February, is cold: the average temperature is just above freezing (0 °C or 32 °F). At night, temperatures are generally around freezing or slightly below, while during the day, they typically exceed freezing by a few degrees. The weather is unstable, in fact, there are sunny days followed by sudden cold air outbreaks, with snowfalls and temperatures around freezing, and wind that can exacerbate the feeling of cold.
In Washington, about 35 centimeters (13.7 inches) of
snow fall per year, while at Dulles Airport, which is actually located 37 km (23 mi) north-west of the city, in the state of Virginia, snowfall reaches 53 cm (20.8 in). Big snowstorms, which can block or hinder many human activities, called
Snowmageddon, occur on average every 4/5 years. The most abundant snowfall in one day was 41.5 cm (16.5 in), in February 1983.
During the most intense cold waves, when the temperature remains below 0 °C (32 °F) even during the day, lows can plunge to -15 °C (5 °F) or below. The record is -20.5 °C (-5 °F), recorded in January 1982.
However, even in winter, there may be some days, or periods lasting a few days, particularly mild, with temperatures reaching 15 °C (59 °F) and sometimes up to 20 °C (68 °F), which confirms the instability of the climate of Washington and in general of the American East Coast.
In
spring, from March to May, the weather continues to be
unstable: the first warm days alternate with the return of cold weather. In March, it can still snow, and sometimes, this can also happen in early April. But already in April, the temperature can sometimes exceed 25 °C (77 °F).
The
National Cherry Blossom Festival lasts three weeks and starts on the last Sunday of March (therefore, it ends in mid-April), when the cherry trees from Japan, donated at the beginning of the 20th century by the mayor of Tokyo, are in bloom.
By May, the average temperatures are pleasant, although there are still cool and rainy days, especially in the first half, while the first heat waves can bring the temperature above 30 °C (86 °F). On sunny days, the first
afternoon thunderstorms can erupt as well.
Summer, from June to August, is
hot and muggy, especially in July and August. There can be days with pleasant temperatures, around 25/27 °C (77/81 °F), maybe with some rain, but more often, there are hot and sultry days, with highs around 30 °C (86 °F).
There may also be
heat waves, which can even last a week, with daytime temperatures reaching or exceeding 35 °C (95 °F) and night temperatures around 25/26 °C (77/79 °F). The highest record is 40.6 °C (105.1 °F) and was set in July 2012.
The amount of sunshine in summer is good, although in fine weather,
thunderstorms can break out in the afternoon, in addition to some weather disturbances, which can bring clouds and rain for a few days.
Autumn, from September to November, is the mildest and the least unstable season of the year, at least in the first part.
In the first half of September, the weather is often still characterized by heat and humidity, with sunshine and some afternoon thunderstorms, then it becomes milder and relatively quiet until mid-October, while in the second half of October, it can start to be a bit cold.
November is a cold month, and the first snowfalls can occur. There a good number of rainy days also in autumn, but this is still the season when the rains are a little less frequent.
The amount of
sunshine in Washington is good in summer, but it is not scarce even in winter because, as mentioned, some sunny days can always occur. On average, there are 2,530 hours of sunshine per year.
The
sea on the Atlantic Coast (see Dewey Beach, Ocean City) is never very warm for swimming, however, it reaches 23.5 °C (74 °F) in August.
Along the coast to the east of Washington, in the Chesapeake Bay (see Chesapeake Beach, Annapolis), about an hour's drive from the city, the sea is a bit colder in winter and a bit warmer in summer, in fact, it reaches 23 °C (73 °F) in July and 24 °C (75 °F) in August.
Best Time
The
best periods to visit Washington are spring and autumn, to avoid both the winter cold and the summer heat, and in particular, from mid-April to mid-May and from mid-September to mid-October. In early September, there is still often sticky weather, though not as hot as in midsummer. In April, it can sometimes get cold and the weather can be unstable, especially at the beginning of the month, while the second half of the month is generally mild.
In autumn (usually, around late October), you can admire the beautiful colors of the trees losing their leaves (the phenomenon called
fall foliage).
The following data was recorded at the
Reagan National Airport, a few kilometers (or miles) south of the city center, in Arlington County, Virginia. Here, a mild microclimate is found because of the Potomac River, which widens to the point of becoming almost a lake, so night temperatures are a couple of degrees Celsius (3.5 °F) higher than in the peripheral districts and in the surrounding countryside.
Washington - Climate data
In Washington, the
average temperature of the coldest month (January) is of
3 °C, that of the warmest month (July) is of
27.2 °C. Here are the average temperatures.
Washington - Average temperatures (1991-2020) |
| Month | Min | Max | Mean |
|---|
| January | -1.1 | 7.1 | 3 |
|---|
| February | -0.1 | 9.1 | 4.5 |
|---|
| March | 3.7 | 13.6 | 8.6 |
|---|
| April | 9.1 | 20 | 14.6 |
|---|
| May | 14.4 | 24.7 | 19.6 |
|---|
| June | 19.7 | 29.5 | 24.6 |
|---|
| July | 22.4 | 32 | 27.2 |
|---|
| August | 21.7 | 31 | 26.4 |
|---|
| September | 17.8 | 27.1 | 22.5 |
|---|
| October | 11.2 | 20.8 | 16 |
|---|
| November | 5.3 | 14.6 | 10 |
|---|
| December | 1.4 | 9.3 | 5.4 |
|---|
| Year | 10.5 | 20 | 15.2 |
|---|
amounts to
1060 millimeters per year: it is therefore quite abundant. It ranges from
65 millimeters in the driest month (February) to
110 millimeters in the wettest one (July). Here is the average precipitation.
Washington - Average precipitation| Month | Days |
|---|
| January | 75 | 10 |
|---|
| February | 65 | 9 |
|---|
| March | 90 | 11 |
|---|
| April | 80 | 11 |
|---|
| May | 100 | 12 |
|---|
| June | 105 | 11 |
|---|
| July | 110 | 10 |
|---|
| August | 85 | 9 |
|---|
| September | 100 | 9 |
|---|
| October | 95 | 8 |
|---|
| November | 75 | 8 |
|---|
| December | 85 | 10 |
|---|
| Year | 1060 | 118 |
|---|
There are on average around 2530
sunshine hours per year. Here are the average hours of sunshine per day.
Washington - Sunshine hours| Month | Average | Total |
|---|
| January | 4.5 | 145 |
|---|
| February | 5.5 | 155 |
|---|
| March | 6.5 | 205 |
|---|
| April | 7.5 | 230 |
|---|
| May | 8.5 | 260 |
|---|
| June | 9.5 | 285 |
|---|
| July | 9 | 280 |
|---|
| August | 8.5 | 265 |
|---|
| September | 7.5 | 225 |
|---|
| October | 6.5 | 205 |
|---|
| November | 5 | 150 |
|---|
| December | 4.5 | 135 |
|---|
| Year | 6.9 | 2530 |
|---|
Washington - Weather by month
Based on the period 1991-2020
January, the coldest month of the year, is generally a cold month. The average temperature is of
3 °C, with a minimum of
-1.1 °C and a maximum of
7.1 °C.
On the coldest nights of the month, the temperature usually drops to around
-10 °C. However, it dropped to
-20 °C in January 1994.
On the warmest days of the month, the temperature usually reaches around
19.5 °C. However, it reached
25 °C in January 2002.
Precipitation amounts to
75 mm, distributed over 10 days.
The day lasts on average 9 hours and 50 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 47% of the time.
The average humidity is 62%.
The average wind speed is of
15.2 kph.
February is generally a quite cold month. The average temperature is of
4.5 °C, with a minimum of
-0.1 °C and a maximum of
9.1 °C.
On the coldest nights of the month, the temperature usually drops to around
-8.5 °C. However, it dropped to
-15 °C in February 1996.
On the warmest days of the month, the temperature usually reaches around
20 °C. However, it reached
27.8 °C in February 2018.
Precipitation amounts to
65 mm, distributed over 9 days.
The day lasts on average 10 hours and 50 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 59%.
The average wind speed is of
15.2 kph.
March is generally a mild month. The average temperature is of
8.6 °C, with a minimum of
3.7 °C and a maximum of
13.6 °C.
On the coldest nights of the month, the temperature usually drops to around
-5 °C. However, it dropped to
-10 °C in March 2009.
On the warmest days of the month, the temperature usually reaches around
25 °C. However, it reached
31 °C in March 1998.
Precipitation amounts to
90 mm, distributed over 11 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 55% of the time.
The average humidity is 57%.
The average wind speed is of
16.5 kph.
April is generally a very mild month. The average temperature is of
14.6 °C, with a minimum of
9.1 °C and a maximum of
20 °C.
On the coldest nights of the month, the temperature usually drops to around
1.5 °C. However, it dropped to
-2 °C in April 1997.
On the warmest days of the month, the temperature usually reaches around
30.5 °C. However, it reached
35 °C in April 2002.
Precipitation amounts to
80 mm, distributed over 11 days.
The day lasts on average 13 hours and 20 minutes.
There are on average 7.5 hours of sunshine per day. So, the sun shines 57% of the time.
The average humidity is 58%.
The average wind speed is of
15.7 kph.
May is generally a warm month. The average temperature is of
19.6 °C, with a minimum of
14.4 °C and a maximum of
24.7 °C.
On the coldest nights of the month, the temperature usually drops to around
7 °C. However, it dropped to
1 °C in May 1997.
On the warmest days of the month, the temperature usually reaches around
33 °C. However, it reached
36.7 °C in May 1991.
Precipitation amounts to
100 mm, distributed over 12 days.
The day lasts on average 14 hours and 20 minutes. So the days are long.
There are on average 8.5 hours of sunshine per day. So, the sun shines 59% of the time.
The average humidity is 65%.
The average wind speed is of
14 kph.
June is generally a warm to hot month. The average temperature is of
24.6 °C, with a minimum of
19.7 °C and a maximum of
29.5 °C.
On the coldest nights of the month, the temperature usually drops to around
13 °C. However, it dropped to
9.4 °C in June 1996.
On the warmest days of the month, the temperature usually reaches around
35.5 °C. However, it reached
40 °C in June 2012.
Precipitation amounts to
105 mm, distributed over 11 days.
The day lasts on average 14 hours and 55 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 9.5 hours of sunshine per day. So, the sun shines 63% of the time.
The average humidity is 65%.
The average wind speed is of
13.6 kph.
July, the hottest month of the year, is generally a warm to hot month. The average temperature is of
27.2 °C, with a minimum of
22.4 °C and a maximum of
32 °C.
On the coldest nights of the month, the temperature usually drops to around
17.5 °C. However, it dropped to
13.9 °C in July 2004.
On the warmest days of the month, the temperature usually reaches around
36.5 °C. However, it reached
40.6 °C in July 2012.
Precipitation amounts to
110 mm, distributed over 10 days.
The day lasts on average 14 hours and 35 minutes. So the days are long.
There are on average 9 hours of sunshine per day. So, the sun shines 62% of the time.
The average humidity is 64%.
The average wind speed is of
12.6 kph.
August is generally a warm to hot month. The average temperature is of
26.4 °C, with a minimum of
21.7 °C and a maximum of
31 °C.
On the coldest nights of the month, the temperature usually drops to around
16.5 °C. However, it dropped to
11.6 °C in August 2004.
On the warmest days of the month, the temperature usually reaches around
36 °C. However, it reached
39 °C in August 1997.
Precipitation amounts to
85 mm, distributed over 9 days.
The day lasts on average 13 hours and 35 minutes.
There are on average 8.5 hours of sunshine per day. So, the sun shines 62% of the time.
The average humidity is 66%.
The average wind speed is of
12.2 kph.
September is generally a warm month. The average temperature is of
22.5 °C, with a minimum of
17.8 °C and a maximum of
27.1 °C.
On the coldest nights of the month, the temperature usually drops to around
11 °C. However, it dropped to
6.7 °C in September 1992.
On the warmest days of the month, the temperature usually reaches around
33.5 °C. However, it reached
37.2 °C in September 2010.
Precipitation amounts to
100 mm, distributed over 9 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 7.5 hours of sunshine per day. So, the sun shines 60% of the time.
The average humidity is 68%.
The average wind speed is of
12.9 kph.
October is generally a very mild month. The average temperature is of
16 °C, with a minimum of
11.2 °C and a maximum of
20.8 °C.
On the coldest nights of the month, the temperature usually drops to around
3.5 °C. However, it dropped to
-2.3 °C in October 1992.
On the warmest days of the month, the temperature usually reaches around
29 °C. However, it reached
36.7 °C in October 2019.
Precipitation amounts to
95 mm, distributed over 8 days.
The day lasts on average 11 hours and 5 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 59% of the time.
The average humidity is 68%.
The average wind speed is of
13.1 kph.
November is generally a mild month. The average temperature is of
10 °C, with a minimum of
5.3 °C and a maximum of
14.6 °C.
On the coldest nights of the month, the temperature usually drops to around
-1.5 °C. However, it dropped to
-5.6 °C in November 2014.
On the warmest days of the month, the temperature usually reaches around
24 °C. However, it reached
28.3 °C in November 1993.
Precipitation amounts to
75 mm, distributed over 8 days.
The day lasts on average 10 hours and 0 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 50% of the time.
The average humidity is 64%.
The average wind speed is of
13.7 kph.
December is generally a quite cold month. The average temperature is of
5.4 °C, with a minimum of
1.4 °C and a maximum of
9.3 °C.
On the coldest nights of the month, the temperature usually drops to around
-6 °C. However, it dropped to
-12 °C in December 2004.
On the warmest days of the month, the temperature usually reaches around
19.5 °C. However, it reached
26 °C in December 1998.
Precipitation amounts to
85 mm, distributed over 10 days.
The day lasts on average 9 hours and 30 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 4.5 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 64%.
The average wind speed is of
13.9 kph.