May weather in Grand Coulee, WA
The average temperature in Grand Coulee in May is 58.3°F (45.8°F–70.8°F). Average precipitation: 1.11 inches.
May is a spring month in Grand Coulee, and is warmer than the annual average of 49.9°F. Daily temperatures swing about 25°F between overnight low and afternoon high. Expect about 8 days with precipitation. Daylight averages about 14h 57m. For travel, May is a comfortable month to visit.
Avg High
70.8°F
Avg Low
45.8°F
Precipitation
1.11 in
Daylight
14h 57m
May records in Grand Coulee
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| May 1 | 84.9°F (1937) | 27.0°F (1954) | 0.68 in (1950) |
| May 2 | 88.0°F (1937) | 32.0°F (1948) | 0.90 in (1950) |
| May 3 | 90.0°F (1937) | 33.1°F (1963) | 0.40 in (1988) |
| May 4 | 88.0°F (1966) | 32.0°F (1949) | 0.64 in (1960) |
| May 5 | 93.0°F (1966) | 30.9°F (1959) | 0.45 in (2017) |
| May 6 | 90.0°F (1992) | 28.9°F (1965) | 0.72 in (1981) |
| May 7 | 91.9°F (1987) | 32.0°F (2002) | 0.45 in (1999) |
| May 8 | 95.0°F (1987) | 28.9°F (2002) | 0.56 in (1991) |
| May 9 | 93.0°F (1987) | 30.0°F (1982) | 1.00 in (1962) |
| May 10 | 91.0°F (1949) | 32.0°F (1999) | 0.94 in (2005) |
| May 11 | 91.0°F (1949) | 34.0°F (1943) | 0.86 in (1975) |
| May 12 | 91.0°F (1949) | 32.0°F (1985) | 0.30 in (2004) |
| May 13 | 93.0°F (1939) | 33.1°F (2004) | 0.40 in (1941) |
| May 14 | 93.9°F (1939) | 32.0°F (1955) | 0.30 in (1978) |
| May 15 | 96.1°F (1939) | 30.0°F (1974) | 0.61 in (2005) |
| May 16 | 93.9°F (1973) | 30.9°F (1974) | 1.10 in (2011) |
| May 17 | 91.9°F (2006) | 30.9°F (1974) | 1.05 in (2019) |
| May 18 | 91.9°F (2006) | 33.1°F (2003) | 1.23 in (1972) |
| May 19 | 91.0°F (2006) | 35.1°F (1987) | 0.85 in (1957) |
| May 20 | 89.1°F (2023) | 36.0°F (1975) | 0.77 in (2006) |
| May 21 | 90.0°F (1958) | 34.0°F (2010) | 0.92 in (1972) |
| May 22 | 91.9°F (1940) | 34.0°F (1960) | 0.85 in (1996) |
| May 23 | 95.0°F (1940) | 35.1°F (1964) | 0.75 in (1989) |
| May 24 | 91.9°F (2001) | 36.0°F (2010) | 0.41 in (1962) |
| May 25 | 95.0°F (1936) | 36.0°F (1964) | 0.66 in (1981) |
| May 26 | 99.0°F (1936) | 35.1°F (1986) | 0.79 in (1980) |
| May 27 | 95.0°F (1936) | 36.0°F (1977) | 0.80 in (1980) |
| May 28 | 93.0°F (1983) | 36.0°F (1970) | 0.97 in (1989) |
| May 29 | 97.0°F (1983) | 34.0°F (1951) | 0.95 in (1948) |
| May 30 | 100.0°F (1986) | 37.0°F (1951) | 0.30 in (2015) |
| May 31 | 99.0°F (1986) | 36.0°F (1984) | 1.35 in (1941) |