Climate data for Washington, D.C. (Reagan National Airport), 1991−2020 normals,[a] extremes 1872−present[b]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 80
(27) 		84
(29) 		93
(34) 		95
(35) 		99
(37) 		104
(40) 		106
(41) 		106
(41) 		104
(40) 		98
(37) 		86
(30) 		79
(26) 		106
(41)
Mean maximum °F (°C) 66.7
(19.3) 		68.1
(20.1) 		77.3
(25.2) 		86.4
(30.2) 		91.0
(32.8) 		95.7
(35.4) 		98.1
(36.7) 		96.5
(35.8) 		91.9
(33.3) 		84.5
(29.2) 		74.8
(23.8) 		67.1
(19.5) 		99.1
(37.3)
Mean daily maximum °F (°C) 44.8
(7.1) 		48.3
(9.1) 		56.5
(13.6) 		68.0
(20.0) 		76.5
(24.7) 		85.1
(29.5) 		89.6
(32.0) 		87.8
(31.0) 		80.7
(27.1) 		69.4
(20.8) 		58.2
(14.6) 		48.8
(9.3) 		67.8
(19.9)
Daily mean °F (°C) 37.5
(3.1) 		40.0
(4.4) 		47.6
(8.7) 		58.2
(14.6) 		67.2
(19.6) 		76.3
(24.6) 		81.0
(27.2) 		79.4
(26.3) 		72.4
(22.4) 		60.8
(16.0) 		49.9
(9.9) 		41.7
(5.4) 		59.3
(15.2)
Mean daily minimum °F (°C) 30.1
(−1.1) 		31.8
(−0.1) 		38.6
(3.7) 		48.4
(9.1) 		58.0
(14.4) 		67.5
(19.7) 		72.4
(22.4) 		71.0
(21.7) 		64.1
(17.8) 		52.2
(11.2) 		41.6
(5.3) 		34.5
(1.4) 		50.9
(10.5)
Mean minimum °F (°C) 14.3
(−9.8) 		16.9
(−8.4) 		23.4
(−4.8) 		34.9
(1.6) 		45.5
(7.5) 		55.7
(13.2) 		63.8
(17.7) 		62.1
(16.7) 		51.3
(10.7) 		38.7
(3.7) 		28.8
(−1.8) 		21.3
(−5.9) 		12.3
(−10.9)
Record low °F (°C) −14
(−26) 		−15
(−26) 		4
(−16) 		15
(−9) 		33
(1) 		43
(6) 		52
(11) 		49
(9) 		36
(2) 		26
(−3) 		11
(−12) 		−13
(−25) 		−15
(−26)
Average precipitation inches (mm) 2.86
(73) 		2.62
(67) 		3.50
(89) 		3.21
(82) 		3.94
(100) 		4.20
(107) 		4.33
(110) 		3.25
(83) 		3.93
(100) 		3.66
(93) 		2.91
(74) 		3.41
(87) 		41.82
(1,062)
Average snowfall inches (cm) 4.9
(12) 		5.0
(13) 		2.0
(5.1) 		0.0
(0.0) 		0.0
(0.0) 		0.0
(0.0) 		0.0
(0.0) 		0.0
(0.0) 		0.0
(0.0) 		0.0
(0.0) 		0.1
(0.25) 		1.7
(4.3) 		13.7
(35)
Average precipitation days (≥ 0.01 in) 9.7 9.3 11.0 10.8 11.6 10.6 10.5 8.7 8.7 8.3 8.4 10.1 117.7
Average snowy days (≥ 0.1 in) 2.8 2.7 1.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 1.3 8.0
Average relative humidity (%) 62.1 60.5 58.6 58.0 64.5 65.8 66.9 69.3 69.7 67.4 64.7 64.1 64.3
Average dew point °F (°C) 21.7
(−5.7) 		23.5
(−4.7) 		31.3
(−0.4) 		39.7
(4.3) 		52.3
(11.3) 		61.5
(16.4) 		66.0
(18.9) 		65.8
(18.8) 		59.5
(15.3) 		47.5
(8.6) 		37.0
(2.8) 		27.1
(−2.7) 		44.4
(6.9)
Mean monthly sunshine hours 144.6 151.8 204.0 228.2 260.5 283.2 280.5 263.1 225.0 203.6 150.2 133.0 2,527.7
Percent possible sunshine 48 50 55 57 59 64 62 62 60 59 50 45 57
Average ultraviolet index 2 3 5 7 8 9 9 8 7 4 3 2 6
Source 1: NOAA (relative humidity, dew point and sun 1961−1990)[2][3][4][5]
Source 2: Weather Atlas (UV)[6]

Notes

  1. ^ Mean monthly maxima and minima (i.e. the expected highest and lowest temperature readings at any point during the year or given month) calculated based on data at said location from 1991 to 2020.
  2. ^ Official records for Washington, D.C. were kept at 24th and M Streets NW from January 1872 to June 1945, and at Reagan National Airport since July 1945.[1]

References

  1. ^ "Threaded Station Extremes". threadex.rcc-acis.org.
  2. ^ "NowData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved May 24, 2021.
  3. ^ "Summary of Monthly Normals 1991–2020". National Oceanic and Atmospheric Administration. Retrieved May 4, 2021.
  4. ^ "WMO Climate Normals for WASHINGTON DC/NATIONAL ARPT VA 1961–1990". National Oceanic and Atmospheric Administration. Retrieved July 18, 2020.
  5. ^ Rogers, Matt (1 April 2015). "April outlook: Winter be gone! First half of month looks warmer than average". The Washington Post. Retrieved May 24, 2021. For reference, here are the 30-year climatology benchmarks for Reagan National Airport for April, along with our projections for the coming month:...Average snowfall: Trace; Forecast: 0 to trace
  6. ^ "Washington, DC - Detailed climate information and monthly weather forecast". Weather Atlas. Yu Media Group. Retrieved June 29, 2019.
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