Rialto Weather in May
Average highs run from 78°F on May 1 to 83°F on May 31, and lows from 53°F to 57°F. Normal precipitation for the month is 0.29 in over about 2 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
- 80°F
- Average low
- 55°F
- Precipitation
- 0.29 in
- Record high
- 109°FMay 29, 1984
- Record low
- 33°FMay 10, 1922
- Chance of a freeze
- 0%
- Days of 90°F or more
- 5.5
- Daylight
- 13 h 34 min to 14 h 16 min
- Cloud cover
- 26%
- Humidity
- 56%
- Dew point
- 44°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 | 78°F | 53°F | 96°F 1947 | 38°F 1913 | 9% |
| May 2 | 78°F | 53°F | 101°F 1966 | 35°F 1913 | 9% |
| May 3 | 78°F | 53°F | 102°F 2004 | 36°F 1938 | 9% |
| May 4 | 78°F | 53°F | 99°F 1987 | 39°F 1938 | 9% |
| May 5 | 78°F | 53°F | 104°F 1990 | 38°F 1920 | 9% |
| May 6 | 79°F | 54°F | 101°F 1987 | 39°F 1975 | 9% |
| May 7 | 79°F | 54°F | 99°F 1923 | 38°F 1933 | 8% |
| May 8 | 79°F | 54°F | 100°F 1923 | 37°F 1930 | 8% |
| May 9 | 79°F | 54°F | 99°F 1923 | 38°F 1930 | 8% |
| May 10 | 79°F | 54°F | 102°F 1934 | 33°F 1922 | 8% |
| May 11 | 80°F | 54°F | 102°F 1960 | 39°F 1922 | 8% |
| May 12 | 80°F | 54°F | 104°F 2013 | 40°F 1905 | 8% |
| May 13 | 80°F | 55°F | 105°F 1927 | 41°F 1907 | 8% |
| May 14 | 80°F | 55°F | 103°F 1927 | 43°F 1942 | 7% |
| May 15 | 80°F | 55°F | 99°F 1905 | 42°F 1955 | 7% |
| May 16 | 80°F | 55°F | 103°F 1970 | 40°F 1933 | 7% |
| May 17 | 81°F | 55°F | 103°F 2008 | 44°F 1899 | 7% |
| May 18 | 81°F | 55°F | 103°F 2008 | 41°F 1977 | 7% |
| May 19 | 81°F | 55°F | 100°F 2008 | 41°F 1923 | 6% |
| May 20 | 81°F | 55°F | 103°F 1942 | 39°F 1948 | 6% |
| May 21 | 81°F | 56°F | 105°F 1967 | 39°F 1948 | 6% |
| May 22 | 82°F | 56°F | 99°F 2005 | 41°F 1903 | 6% |
| May 23 | 82°F | 56°F | 100°F 2001 | 41°F 1960 | 6% |
| May 24 | 82°F | 56°F | 97°F 1938 | 43°F 1903 | 6% |
| May 25 | 82°F | 56°F | 100°F 1986 | 38°F 1980 | 6% |
| May 26 | 82°F | 56°F | 104°F 1974 | 38°F 1953 | 5% |
| May 27 | 82°F | 56°F | 103°F 1968 | 38°F 1953 | 5% |
| May 28 | 83°F | 56°F | 107°F 2003 | 41°F 1899 | 5% |
| May 29 | 83°F | 56°F | 109°F 1984 | 43°F 1909 | 5% |
| May 30 | 83°F | 56°F | 101°F 1910 | 41°F 1921 | 5% |
| May 31 | 83°F | 57°F | 105°F 1910 | 43°F 1921 | 5% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- May 1
- sunrise 6:00 AM, sunset 7:34 PM
- May 31
- sunrise 5:39 AM, sunset 7:55 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00047473 (Riverside Citrus Exp), public domain. Records: NOAA GHCN-Daily, station USC00047306, 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.