Climate in Washington (D.C.)

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 (37.4 °F), that of the warmest month (July) is of 27.2 °C (81 °F). Here are the average temperatures.
Precipitation amounts to 1060 millimeters (41.7 inches) per year: it is therefore quite abundant. It ranges from 65 mm (2.6 in) in the driest month (February) to 110 mm (4.3 in) in the wettest one (July). Here is the average precipitation.
There are on average around 2530 sunshine hours per year. Here are the average hours of sunshine per day.

Washington - Weather by month

Based on the period 1991-2020

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January, the coldest month of the year, is generally a cold month. The average temperature is of 3 °C (37 °F), with a minimum of -1.1 °C (30 °F) and a maximum of 7.1 °C (44.8 °F).
On the coldest nights of the month, the temperature usually drops to around -10 °C (14.5 °F). However, it dropped to -20 °C (-4 °F) in January 1994.
On the warmest days of the month, the temperature usually reaches around 19.5 °C (67 °F). However, it reached 25 °C (77 °F) in January 2002.
Precipitation amounts to 75 mm (3 in), 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 15 kph (9 mph).

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February is generally a quite cold month. The average temperature is of 4.5 °C (40 °F), with a minimum of -0.1 °C (31.8 °F) and a maximum of 9.1 °C (48.4 °F).
On the coldest nights of the month, the temperature usually drops to around -8.5 °C (16.5 °F). However, it dropped to -15 °C (5 °F) in February 1996.
On the warmest days of the month, the temperature usually reaches around 20 °C (68 °F). However, it reached 27.8 °C (82 °F) in February 2018.
Precipitation amounts to 65 mm (2.6 in), 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 15 kph (9 mph).

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March is generally a mild month. The average temperature is of 8.6 °C (48 °F), with a minimum of 3.7 °C (38.7 °F) and a maximum of 13.6 °C (56.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around -5 °C (23 °F). However, it dropped to -10 °C (14 °F) in March 2009.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 25 °C (77.5 °F). However, it reached 31 °C (87.8 °F) in March 1998.
Precipitation amounts to 90 mm (3.5 in), 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 16 kph (10 mph).

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April is generally a very mild month. The average temperature is of 14.6 °C (58 °F), with a minimum of 9.1 °C (48.4 °F) and a maximum of 20 °C (68 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 1.5 °C (34.5 °F). However, it dropped to -2 °C (28.4 °F) in April 1997.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 30.5 °C (86.5 °F). However, it reached 35 °C (95 °F) in April 2002.
Precipitation amounts to 80 mm (3.1 in), 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 16 kph (10 mph).

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May is generally a warm month. The average temperature is of 19.6 °C (67 °F), with a minimum of 14.4 °C (57.9 °F) and a maximum of 24.7 °C (76.5 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 7 °C (45 °F). However, it dropped to 1 °C (33.8 °F) in May 1997.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 33 °C (91 °F). However, it reached 36.7 °C (98.1 °F) in May 1991.
Precipitation amounts to 100 mm (3.9 in), 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 14 kph (9 mph).

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June is generally a warm to hot month. The average temperature is of 24.6 °C (76 °F), with a minimum of 19.7 °C (67.5 °F) and a maximum of 29.5 °C (85.1 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 13 °C (55 °F). However, it dropped to 9.4 °C (48.9 °F) in June 1996.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 35.5 °C (95.5 °F). However, it reached 40 °C (104 °F) in June 2012.
Precipitation amounts to 105 mm (4.1 in), 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 14 kph (8 mph).

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July, the hottest month of the year, is generally a warm to hot month. The average temperature is of 27.2 °C (81 °F), with a minimum of 22.4 °C (72.3 °F) and a maximum of 32 °C (89.6 °F).
On the coldest nights of the month, the temperature usually drops to around 17.5 °C (63.5 °F). However, it dropped to 13.9 °C (57 °F) in July 2004.
On the warmest days of the month, the temperature usually reaches around 36.5 °C (98 °F). However, it reached 40.6 °C (105.1 °F) in July 2012.
Precipitation amounts to 110 mm (4.3 in), 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 13 kph (8 mph).

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August is generally a warm to hot month. The average temperature is of 26.4 °C (79 °F), with a minimum of 21.7 °C (71.1 °F) and a maximum of 31 °C (87.8 °F).
On the coldest nights of the month, the temperature usually drops to around 16.5 °C (62 °F). However, it dropped to 11.6 °C (52.9 °F) in August 2004.
On the warmest days of the month, the temperature usually reaches around 36 °C (96.5 °F). However, it reached 39 °C (102.2 °F) in August 1997.
Precipitation amounts to 85 mm (3.3 in), 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 12 kph (8 mph).

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September is generally a warm month. The average temperature is of 22.5 °C (72 °F), with a minimum of 17.8 °C (64 °F) and a maximum of 27.1 °C (80.8 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 11 °C (51.5 °F). However, it dropped to 6.7 °C (44.1 °F) in September 1992.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 33.5 °C (92 °F). However, it reached 37.2 °C (99 °F) in September 2010.
Precipitation amounts to 100 mm (3.9 in), 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 13 kph (8 mph).

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October is generally a very mild month. The average temperature is of 16 °C (61 °F), with a minimum of 11.2 °C (52.2 °F) and a maximum of 20.8 °C (69.4 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 3.5 °C (38.5 °F). However, it dropped to -2.3 °C (27.9 °F) in October 1992.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 29 °C (84.5 °F). However, it reached 36.7 °C (98.1 °F) in October 2019.
Precipitation amounts to 95 mm (3.7 in), 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 13 kph (8 mph).

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November is generally a mild month. The average temperature is of 10 °C (50 °F), with a minimum of 5.3 °C (41.5 °F) and a maximum of 14.6 °C (58.3 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around -1.5 °C (29 °F). However, it dropped to -5.6 °C (21.9 °F) in November 2014.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 24 °C (75.5 °F). However, it reached 28.3 °C (82.9 °F) in November 1993.
Precipitation amounts to 75 mm (3 in), 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 14 kph (8 mph).

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December is generally a quite cold month. The average temperature is of 5.4 °C (42 °F), with a minimum of 1.4 °C (34.5 °F) and a maximum of 9.3 °C (48.7 °F).
On the coldest nights of the month, the temperature usually drops to around -6 °C (21 °F). However, it dropped to -12 °C (10.4 °F) in December 2004.
On the warmest days of the month, the temperature usually reaches around 19.5 °C (67 °F). However, it reached 26 °C (78.8 °F) in December 1998.
Precipitation amounts to 85 mm (3.3 in), 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 14 kph (9 mph).