Ontario Weather in August
Average highs run from 83°F on August 1 to 80°F on August 31, and lows from 61°F to 58°F. Normal precipitation for the month is 3.51 in over about 10 wet days.
August day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
August at a glance
- Average high
- 82°F
- Average low
- 60°F
- Precipitation
- 3.51 in
- Record high
- 97°FAug 17, 1988
- Record low
- 40°FAug 29, 1965
- Chance of a freeze
- 0%
- Days of 90°F or more
- 1.8
- Daylight
- 14 h 19 min to 13 h 08 min
- Cloud cover
- 65%
- Humidity
- 72%
- Dew point
- 61°F
- Wind
- 7.6 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.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Aug 1 | 83°F | 61°F | 93°F 2002 | 48°F 1952 | 35% | 0% |
| Aug 2 | 83°F | 61°F | 95°F 1964 | 49°F 1976 | 35% | 0% |
| Aug 3 | 83°F | 61°F | 94°F 1955 | 44°F 1965 | 35% | 0% |
| Aug 4 | 83°F | 61°F | 93°F 1955 | 49°F 1966 | 35% | 0% |
| Aug 5 | 83°F | 60°F | 93°F 1955 | 48°F 1972 | 34% | 0% |
| Aug 6 | 83°F | 60°F | 91°F 2018 | 45°F 1997 | 34% | 0% |
| Aug 7 | 83°F | 60°F | 90°F 1996 | 49°F 1997 | 34% | 0% |
| Aug 8 | 82°F | 60°F | 92°F 1983 | 46°F 1989 | 34% | 0% |
| Aug 9 | 82°F | 60°F | 91°F 1949 | 49°F 1999 | 33% | 0% |
| Aug 10 | 82°F | 60°F | 92°F 1949 | 49°F 1972 | 33% | 0% |
| Aug 11 | 82°F | 60°F | 92°F 2016 | 46°F 1967 | 33% | 0% |
| Aug 12 | 82°F | 60°F | 91°F 1988 | 46°F 1967 | 33% | 0% |
| Aug 13 | 82°F | 60°F | 92°F 1995 | 48°F 1964 | 33% | 0% |
| Aug 14 | 82°F | 60°F | 91°F 1988 | 45°F 1964 | 33% | 0% |
| Aug 15 | 82°F | 60°F | 91°F 1965 | 46°F 1963 | 32% | 0% |
| Aug 16 | 82°F | 60°F | 92°F 1965 | 44°F 1979 | 32% | 0% |
| Aug 17 | 82°F | 60°F | 97°F 1988 | 47°F 1976 | 32% | 0% |
| Aug 18 | 82°F | 60°F | 92°F 2019 | 50°F 1963 | 32% | 0% |
| Aug 19 | 82°F | 60°F | 93°F 1955 | 49°F 1953 | 32% | 0% |
| Aug 20 | 82°F | 60°F | 93°F 1983 | 48°F 1949 | 32% | 0% |
| Aug 21 | 82°F | 59°F | 92°F 1955 | 43°F 1950 | 32% | 0% |
| Aug 22 | 82°F | 59°F | 91°F 1968 | 48°F 1982 | 32% | 0% |
| Aug 23 | 82°F | 59°F | 92°F 1968 | 47°F 1952 | 31% | 0% |
| Aug 24 | 81°F | 59°F | 93°F 1968 | 46°F 1951 | 31% | 0% |
| Aug 25 | 81°F | 59°F | 91°F 2024 | 47°F 1986 | 31% | 0% |
| Aug 26 | 81°F | 59°F | 92°F 1953 | 47°F 1963 | 31% | 0% |
| Aug 27 | 81°F | 59°F | 93°F 1983 | 48°F 2010 | 31% | 0% |
| Aug 28 | 81°F | 58°F | 93°F 2024 | 41°F 1965 | 31% | 0% |
| Aug 29 | 81°F | 58°F | 93°F 1953 | 40°F 1965 | 31% | 0% |
| Aug 30 | 81°F | 58°F | 95°F 2024 | 42°F 1976 | 31% | 0% |
| Aug 31 | 80°F | 58°F | 93°F 1951 | 45°F 2009 | 31% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (EDT).
- August 1
- sunrise 6:27 AM, sunset 8:46 PM
- August 31
- sunrise 6:56 AM, sunset 8:04 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00334874 (Mansfield 5 W), public domain. Records: NOAA GHCN-Daily, station USW00014891, 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.