Coulee Dam Weather in May
Average highs run from 66°F on May 1 to 74°F on May 31, and lows from 42°F to 49°F. Normal precipitation for the month is 1.11 in over about 8 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
- 71°F
- Average low
- 46°F
- Precipitation
- 1.11 in
- Record high
- 100°FMay 30, 1986
- Record low
- 27°FMay 1, 1954
- Chance of a freeze
- 23%
- Days of 90°F or more
- 0.6
- Daylight
- 14 h 31 min to 15 h 46 min
- Cloud cover
- 64%
- Humidity
- 58%
- Dew point
- 39°F
- Wind
- 6.3 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 | 66°F | 42°F | 85°F 1937 | 27°F 1954 | 26% |
| May 2 | 67°F | 42°F | 88°F 1937 | 32°F 1948 | 26% |
| May 3 | 67°F | 42°F | 90°F 1937 | 33°F 1963 | 26% |
| May 4 | 67°F | 43°F | 88°F 1966 | 32°F 1949 | 26% |
| May 5 | 68°F | 43°F | 93°F 1966 | 31°F 1959 | 26% |
| May 6 | 68°F | 43°F | 90°F 1992 | 29°F 1965 | 26% |
| May 7 | 68°F | 43°F | 92°F 1987 | 32°F 2002 | 26% |
| May 8 | 69°F | 44°F | 95°F 1987 | 29°F 2002 | 26% |
| May 9 | 69°F | 44°F | 93°F 1987 | 30°F 1982 | 26% |
| May 10 | 69°F | 44°F | 91°F 1949 | 32°F 1999 | 26% |
| May 11 | 70°F | 45°F | 91°F 1949 | 34°F 1943 | 26% |
| May 12 | 70°F | 45°F | 91°F 1949 | 32°F 1985 | 26% |
| May 13 | 70°F | 45°F | 93°F 1939 | 33°F 2004 | 27% |
| May 14 | 71°F | 46°F | 94°F 1939 | 32°F 1955 | 27% |
| May 15 | 71°F | 46°F | 96°F 1939 | 30°F 1974 | 27% |
| May 16 | 71°F | 46°F | 94°F 1973 | 31°F 1974 | 27% |
| May 17 | 71°F | 46°F | 92°F 2006 | 31°F 1974 | 27% |
| May 18 | 72°F | 47°F | 92°F 2006 | 33°F 2003 | 27% |
| May 19 | 72°F | 47°F | 91°F 2006 | 35°F 1987 | 27% |
| May 20 | 72°F | 47°F | 89°F 2023 | 36°F 1975 | 27% |
| May 21 | 72°F | 47°F | 90°F 1958 | 34°F 2010 | 27% |
| May 22 | 73°F | 48°F | 92°F 1940 | 34°F 1960 | 27% |
| May 23 | 73°F | 48°F | 95°F 1940 | 35°F 1964 | 27% |
| May 24 | 73°F | 48°F | 92°F 2001 | 36°F 2010 | 28% |
| May 25 | 73°F | 48°F | 95°F 1936 | 36°F 1964 | 28% |
| May 26 | 73°F | 48°F | 99°F 1936 | 37°F 1954 | 27% |
| May 27 | 74°F | 49°F | 95°F 1936 | 36°F 1977 | 27% |
| May 28 | 74°F | 49°F | 93°F 1983 | 36°F 1970 | 27% |
| May 29 | 74°F | 49°F | 97°F 1983 | 34°F 1951 | 27% |
| May 30 | 74°F | 49°F | 100°F 1986 | 37°F 1951 | 27% |
| May 31 | 74°F | 49°F | 99°F 1986 | 36°F 1984 | 27% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- May 1
- sunrise 5:38 AM, sunset 8:09 PM
- May 31
- sunrise 5:01 AM, sunset 8:47 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00451767 (Coulee Dam 1 Sw), public domain. Records: NOAA GHCN-Daily, station USC00451767, 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.