Fairfax Weather in May
Average highs run from 70°F on May 1 to 75°F on May 31, and lows from 49°F to 52°F. Normal precipitation for the month is 0.94 in over about 3 wet days.
May day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
May at a glance
- Average high
- 72°F
- Average low
- 51°F
- Precipitation
- 0.94 in
- Record high
- 101°FMay 12, 1976
- Record low
- 27°FMay 10, 1985
- Chance of a freeze
- 0%
- Days of 90°F or more
- 1.3
- Daylight
- 13 h 47 min to 14 h 37 min
- Cloud cover
- 41%
- Humidity
- 78%
- Dew point
- 49°F
- Wind
- 8.5 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| May 1 | 70°F | 49°F | 91°F 1947 | 34°F 1933 | 15% |
| May 2 | 70°F | 49°F | 91°F 1966 | 33°F 1915 | 15% |
| May 3 | 70°F | 49°F | 91°F 2013 | 34°F 1913 | 14% |
| May 4 | 70°F | 49°F | 91°F 2013 | 32°F 1917 | 14% |
| May 5 | 70°F | 49°F | 96°F 1987 | 32°F 1930 | 13% |
| May 6 | 70°F | 49°F | 97°F 1987 | 34°F 1930 | 13% |
| May 7 | 71°F | 50°F | 98°F 1987 | 31°F 1930 | 13% |
| May 8 | 71°F | 50°F | 92°F 1931 | 32°F 1930 | 12% |
| May 9 | 71°F | 50°F | 94°F 1931 | 31°F 1930 | 12% |
| May 10 | 71°F | 50°F | 92°F 1934 | 27°F 1985 | 12% |
| May 11 | 71°F | 50°F | 92°F 1959 | 32°F 1930 | 11% |
| May 12 | 71°F | 50°F | 101°F 1976 | 36°F 1916 | 11% |
| May 13 | 71°F | 50°F | 95°F 1972 | 35°F 1917 | 11% |
| May 14 | 72°F | 50°F | 95°F 1970 | 34°F 1918 | 11% |
| May 15 | 72°F | 51°F | 100°F 2008 | 34°F 1917 | 10% |
| May 16 | 72°F | 51°F | 95°F 1956 | 35°F 1930 | 10% |
| May 17 | 72°F | 51°F | 99°F 1997 | 34°F 1930 | 10% |
| May 18 | 72°F | 51°F | 92°F 1997 | 34°F 1918 | 10% |
| May 19 | 72°F | 51°F | 94°F 1931 | 33°F 1918 | 9% |
| May 20 | 73°F | 51°F | 96°F 1988 | 33°F 1918 | 9% |
| May 21 | 73°F | 51°F | 92°F 2000 | 34°F 1929 | 9% |
| May 22 | 73°F | 51°F | 95°F 1943 | 37°F 1922 | 9% |
| May 23 | 73°F | 51°F | 97°F 1943 | 38°F 1917 | 8% |
| May 24 | 73°F | 52°F | 99°F 1982 | 34°F 1925 | 8% |
| May 25 | 74°F | 52°F | 95°F 1951 | 37°F 1918 | 8% |
| May 26 | 74°F | 52°F | 94°F 1974 | 36°F 1917 | 8% |
| May 27 | 74°F | 52°F | 98°F 1984 | 38°F 1916 | 7% |
| May 28 | 74°F | 52°F | 99°F 1984 | 39°F 1959 | 7% |
| May 29 | 74°F | 52°F | 101°F 1950 | 36°F 1985 | 7% |
| May 30 | 75°F | 52°F | 98°F 2001 | 34°F 1929 | 7% |
| May 31 | 75°F | 52°F | 99°F 1970 | 34°F 1915 | 7% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- May 1
- sunrise 6:14 AM, sunset 8:01 PM
- May 31
- sunrise 5:50 AM, sunset 8:27 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00047880 (San Rafael Civic Ctr), public domain. Records: NOAA GHCN-Daily, station USC00046826, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.