Click on a day for an hourly weather forecast
The temperatures in Olympia in September are comfortable with low of 10°C and and high up to 23°C.
You can expect about 3 to 8 days of rain in Olympia during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Olympia in September 2025.
If you’re planning to visit Olympia in the near future, we highly recommend that you review the 14 day weather forecast for Olympia before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 8° / 2° | 13 | 16 | 2 | 289 mm | Awful | Olympia in January |
| February | 8° / 1° | 11 | 13 | 4 | 202 mm | Awful | Olympia in February |
| March | 11° / 2° | 13 | 17 | 1 | 223 mm | Bad | Olympia in March |
| April | 14° / 4° | 9 | 21 | 0 | 150 mm | Ok | Olympia in April |
| May | 19° / 6° | 6 | 25 | 0 | 94 mm | Good | Olympia in May |
| June | 22° / 8° | 4 | 26 | 0 | 64 mm | Good | Olympia in June |
| July | 27° / 11° | 1 | 30 | 0 | 21 mm | Perfect | Olympia in July |
| August | 27° / 12° | 2 | 29 | 0 | 29 mm | Perfect | Olympia in August |
| September | 23° / 10° | 6 | 24 | 0 | 106 mm | Perfect | Olympia in September |
| October | 16° / 6° | 10 | 21 | 0 | 251 mm | Ok | Olympia in October |
| November | 10° / 4° | 13 | 16 | 1 | 293 mm | Bad | Olympia in November |
| December | 6° / 1° | 12 | 16 | 2 | 262 mm | Awful | Olympia in December |