Click on a day for an hourly weather forecast
The temperatures in Formosa in September are comfortable with low of 16°C and and high up to 28°C.
You can expect about 3 to 8 days of rain in Formosa 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 Formosa in September 2025.
If you’re planning to visit Formosa in the near future, we highly recommend that you review the 14 day weather forecast for Formosa before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 35° / 23° | 8 | 23 | 0 | 163 mm | Bad | Formosa in January |
| February | 34° / 22° | 7 | 21 | 0 | 148 mm | Bad | Formosa in February |
| March | 32° / 20° | 7 | 24 | 0 | 158 mm | Ok | Formosa in March |
| April | 28° / 18° | 6 | 24 | 0 | 169 mm | Perfect | Formosa in April |
| May | 23° / 15° | 7 | 24 | 0 | 148 mm | Good | Formosa in May |
| June | 21° / 13° | 5 | 25 | 0 | 99 mm | Good | Formosa in June |
| July | 21° / 12° | 5 | 26 | 0 | 91 mm | Good | Formosa in July |
| August | 25° / 14° | 3 | 28 | 0 | 54 mm | Perfect | Formosa in August |
| September | 28° / 16° | 4 | 26 | 0 | 78 mm | Perfect | Formosa in September |
| October | 30° / 18° | 9 | 22 | 0 | 216 mm | Ok | Formosa in October |
| November | 32° / 19° | 8 | 22 | 0 | 212 mm | Ok | Formosa in November |
| December | 34° / 21° | 8 | 23 | 0 | 207 mm | Bad | Formosa in December |