Click on a day for an hourly weather forecast
The weather in Sumatra in September is very hot. The average temperatures are between 23°C and 33°C, drinking water regularly is advisable.
You can expect rain for roughly half of the month of September in Sumatra. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Sumatra in September 2025.
If you’re planning to visit Sumatra in the near future, we highly recommend that you review the 14 day weather forecast for Sumatra before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 31° / 22° | 10 | 21 | 0 | 209 mm | Ok | Sumatra in January |
| February | 32° / 22° | 6 | 22 | 0 | 158 mm | Good | Sumatra in February |
| March | 33° / 23° | 9 | 22 | 0 | 190 mm | Ok | Sumatra in March |
| April | 33° / 24° | 12 | 18 | 0 | 242 mm | Ok | Sumatra in April |
| May | 34° / 24° | 13 | 18 | 0 | 254 mm | Bad | Sumatra in May |
| June | 34° / 24° | 11 | 19 | 0 | 184 mm | Bad | Sumatra in June |
| July | 34° / 23° | 9 | 22 | 0 | 168 mm | Bad | Sumatra in July |
| August | 34° / 23° | 11 | 20 | 0 | 209 mm | Bad | Sumatra in August |
| September | 33° / 23° | 13 | 17 | 0 | 229 mm | Ok | Sumatra in September |
| October | 33° / 23° | 14 | 17 | 0 | 308 mm | Ok | Sumatra in October |
| November | 32° / 23° | 15 | 15 | 0 | 317 mm | Ok | Sumatra in November |
| December | 31° / 23° | 13 | 18 | 0 | 285 mm | Ok | Sumatra in December |