Climate averages 1991–2020
Fullerton weather
in August.
A hot, very dry month: the warmest and the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
August is a hot month in Fullerton: daytime highs average 31.6°C and nights cool to about 18.7°C. By daytime temperature it is the warmest month of the year.
Rain is very rare: less than 1 mm falls in a typical August (the driest month of the year). Daylight, from sunrise to sunset, lasts about 13 h 25 min on an average August day.
The nearest other city in this atlas is Anaheim (4 km away). In August its highs average 29.1°C, 2.5°C cooler than Fullerton, with almost no rain (under 1 mm).
Among the 498 cities listed in the United States, Fullerton ranks joint 144th of 498 for the warmest August highs and joint 13th of 498 for the driest August (rainfall, lowest first). The mean August high of those 498 cities is 29.9°C; Fullerton is 1.7°C warmer than that mean.
From August to September, average highs fall by 1.2°C to 30.3°C, and monthly rainfall rises from under 1 mm to 3.6 mm.
The annual picture
August in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Fullerton climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 18.6°C6.7°C | 6.7°C | 71 | 5.2 | 10.210 h |
| February | 18.8°C7.5°C | 7.5°C | 79 | 6.1 | 10.911 h |
| March | 20.3°C9.3°C | 9.3°C | 46 | 5.1 | 12.012 h |
| April | 22.5°C10.9°C | 10.9°C | 18 | 2.6 | 13.013 h |
| May | 24.4°C13.4°C | 13.4°C | 7.4 | 1.5 | 13.914 h |
| June | 27.2°C15.6°C | 15.6°C | 1.8 | 0.3 | 14.414 h |
| July | 30.3°C18.1°C | 18.1°C | 1.3 | 0.4 | 14.214 h |
| August, selected | 31.6°C18.7°C | 18.7°C | 0.4 | 0.1 | 13.413 h |
| September | 30.3°C17.8°C | 17.8°C | 3.6 | 0.5 | 12.412 h |
| October | 26.6°C14.4°C | 14.4°C | 14 | 1.9 | 11.411 h |
| November | 22.4°C10.0°C | 10.0°C | 19 | 2.4 | 10.410 h |
| December | 18.4°C6.5°C | 6.5°C | 48 | 4.9 | 9.910 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
August in nearby cities
- Anaheim in AugustUnited States · 4 kmHigh 29.1°C · Low 17.9°C · 0.4 mm rain
- Buena Park in AugustUnited States · 7 kmHigh 31.2°C · Low 18.4°C · 0.4 mm rain
- Westminster (California), United States in AugustUnited States · 14 kmHigh 28.6°C · Low 17.9°C · 0.4 mm rain
- Santa Ana, United States in AugustUnited States · 15 kmHigh 26.7°C · Low 18.1°C · 0.9 mm rain
- Whittier in AugustUnited States · 16 kmHigh 31.6°C · Low 18.7°C · 0.5 mm rain
- Chino Hills in AugustUnited States · 21 kmHigh 31.2°C · Low 18.4°C · 0.9 mm rain
- Downey in AugustUnited States · 21 kmHigh 30.4°C · Low 18.0°C · 0.3 mm rain
- West Covina in AugustUnited States · 22 kmHigh 32.7°C · Low 19.1°C · 0.5 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Fullerton) is explained once on the Fullerton year overview and on the Sources, method and limits page.
Anaheim, Huntington Beach and Westminster (California), United States lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.