Fairfax climate

Fairfax Weather in May

NOAA 1991-2020 normals for Ralston, 8.5 km from Fairfax

Average highs run from 76°F on May 1 to 84°F on May 31, and lows from 52°F to 63°F. Normal precipitation for the month is 5.36 in over about 8 wet days.

May day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Fairfax, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

May at a glance

Average high
80°F
Average low
58°F
Precipitation
5.36 in
Record high
100°FMay 4, 2014
Record low
30°FMay 2, 1967
Chance of a freeze
5%
Days of 90°F or more
3.6
Daylight
13 h 42 min to 14 h 29 min
Cloud cover
59%
Humidity
76%
Dew point
59°F
Wind
11.0 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
May 176°F52°F90°F 194833°F 199425%0%
May 277°F53°F91°F 195530°F 196725%0%
May 377°F53°F99°F 195031°F 195425%0%
May 477°F53°F100°F 201433°F 200525%0%
May 577°F54°F97°F 201437°F 197925%0%
May 677°F54°F96°F 201440°F 199226%0%
May 778°F55°F94°F 201437°F 196726%0%
May 878°F55°F93°F 201134°F 198426%0%
May 978°F55°F94°F 195637°F 198026%0%
May 1078°F56°F97°F 196741°F 198126%0%
May 1179°F56°F95°F 196335°F 195226%0%
May 1279°F56°F94°F 202234°F 197926%0%
May 1379°F57°F94°F 195632°F 196626%0%
May 1479°F57°F95°F 202537°F 195326%0%
May 1580°F57°F93°F 196637°F 197326%0%
May 1680°F58°F93°F 197438°F 201426%0%
May 1780°F58°F95°F 199738°F 197326%0%
May 1880°F58°F98°F 195641°F 197626%0%
May 1981°F59°F97°F 200640°F 196826%0%
May 2081°F59°F97°F 195639°F 198126%0%
May 2181°F59°F96°F 200543°F 196726%0%
May 2282°F60°F96°F 200043°F 196726%0%
May 2382°F60°F99°F 199646°F 197926%0%
May 2482°F60°F96°F 199640°F 197926%0%
May 2582°F61°F98°F 200642°F 196626%0%
May 2683°F61°F95°F 195344°F 196626%0%
May 2783°F61°F96°F 195845°F 196126%0%
May 2883°F62°F96°F 201248°F 199226%0%
May 2984°F62°F95°F 195340°F 198426%0%
May 3084°F62°F100°F 198546°F 199226%0%
May 3184°F63°F99°F 195343°F 197226%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Fairfax, in percent, and of at least 0.1 inch of snowfall.01020301102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (CDT).

May 1
sunrise 6:33 AM, sunset 8:15 PM
May 31
sunrise 6:10 AM, sunset 8:39 PM

Every day of May: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00347390 (Ralston), public domain. Records: NOAA GHCN-Daily, station USW00013969, 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.