May weather in Index, WA
The average temperature in Index in May is 55.0°F (44.0°F–66.0°F). Average precipitation: 5.02 inches.
May is a spring month in Index, and is warmer than the annual average of 49.8°F. Daily temperatures swing about 22°F between overnight low and afternoon high. Expect about 15 days with precipitation. Daylight averages about 14h 56m. For travel, May is a wet month.
Avg High
66.0°F
Avg Low
44.0°F
Precipitation
5.02 in
Daylight
14h 56m
May records in Index
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| May 1 | 90.0°F (1998) | 30.0°F (1972) | 1.22 in (1997) |
| May 2 | 91.9°F (2014) | 30.9°F (2006) | 1.22 in (1984) |
| May 3 | 87.1°F (2016) | 33.1°F (2010) | 3.10 in (2010) |
| May 4 | 88.0°F (1980) | 34.0°F (2010) | 0.95 in (1985) |
| May 5 | 89.1°F (2017) | 30.9°F (1982) | 1.45 in (2014) |
| May 6 | 81.0°F (1987) | 32.0°F (1970) | 1.19 in (1997) |
| May 7 | 84.9°F (1987) | 33.1°F (2000) | 1.19 in (2022) |
| May 8 | 86.0°F (1987) | 34.0°F (1996) | 0.94 in (2006) |
| May 9 | 87.1°F (2018) | 30.9°F (1996) | 0.95 in (2014) |
| May 10 | 84.0°F (2019) | 32.0°F (1973) | 2.05 in (1992) |
| May 11 | 88.0°F (1971) | 32.0°F (1973) | 1.12 in (1975) |
| May 12 | 86.0°F (2019) | 30.9°F (1985) | 1.77 in (1987) |
| May 13 | 90.0°F (1973) | 35.1°F (1986) | 2.28 in (1986) |
| May 14 | 93.0°F (1973) | 34.0°F (1974) | 1.16 in (1974) |
| May 15 | 90.0°F (2018) | 32.0°F (1986) | 0.83 in (2011) |
| May 16 | 91.9°F (2006) | 34.0°F (1986) | 2.30 in (1971) |
| May 17 | 93.0°F (2008) | 34.0°F (2003) | 1.12 in (2019) |
| May 18 | 95.0°F (2008) | 32.0°F (1976) | 1.32 in (1975) |
| May 19 | 82.0°F (1978) | 33.1°F (1982) | 1.42 in (1984) |
| May 20 | 82.9°F (1978) | 35.1°F (1974) | 1.08 in (1994) |
| May 21 | 86.0°F (1988) | 33.1°F (1973) | 0.97 in (1993) |
| May 22 | 82.0°F (2017) | 37.0°F (1984) | 1.28 in (2012) |
| May 23 | 87.1°F (2017) | 35.1°F (1978) | 1.18 in (2012) |
| May 24 | 87.1°F (1992) | 32.0°F (1975) | 1.24 in (1975) |
| May 25 | 82.9°F (1986) | 35.1°F (1972) | 1.07 in (1998) |
| May 26 | 82.0°F (2005) | 37.0°F (1982) | 1.59 in (1984) |
| May 27 | 88.0°F (2005) | 33.1°F (1973) | 0.86 in (2000) |
| May 28 | 100.0°F (1983) | 34.0°F (1974) | 1.01 in (1988) |
| May 29 | 96.1°F (1983) | 36.0°F (1974) | 1.45 in (1994) |
| May 30 | 86.0°F (2007) | 35.1°F (1978) | 1.72 in (1987) |
| May 31 | 89.1°F (2007) | 36.0°F (1976) | 0.99 in (1990) |