Click on a day for an hourly weather forecast
The weather in Riverside in September is hot. The average temperatures are between 16°C and 31°C. Usually the days in September are hot while the nights are a bit cooler.
There shouldn't be any rainy days in in Riverside during September. Having said that, the days are very hot in September so hanging out outside is more recomanded during the after noons and evening time.
Our weather forecast can give you a great sense of what weather to expect in Riverside in September 2025.
If you’re planning to visit Riverside in the near future, we highly recommend that you review the 14 day weather forecast for Riverside before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 18° / 6° | 3 | 28 | 0 | 44 mm | Good | Riverside in January |
| February | 18° / 6° | 2 | 26 | 0 | 52 mm | Good | Riverside in February |
| March | 20° / 7° | 2 | 29 | 0 | 30 mm | Good | Riverside in March |
| April | 23° / 8° | 1 | 29 | 0 | 19 mm | Perfect | Riverside in April |
| May | 25° / 10° | 1 | 30 | 0 | 10 mm | Perfect | Riverside in May |
| June | 29° / 13° | 0 | 30 | 0 | 3 mm | Good | Riverside in June |
| July | 32° / 17° | 2 | 29 | 0 | 27 mm | Good | Riverside in July |
| August | 33° / 17° | 1 | 30 | 0 | 19 mm | Good | Riverside in August |
| September | 31° / 16° | 0 | 30 | 0 | 11 mm | Good | Riverside in September |
| October | 27° / 12° | 1 | 30 | 0 | 13 mm | Perfect | Riverside in October |
| November | 22° / 9° | 1 | 29 | 0 | 21 mm | Good | Riverside in November |
| December | 17° / 5° | 3 | 28 | 0 | 61 mm | Good | Riverside in December |