Climate averages 1991–2020
Dumai weather
in September.
A hot, very wet month: the joint 6th warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Dumai: daytime highs average 30.2°C and nights cool to about 23.6°C. By daytime temperature it is the joint 6th warmest of the 12 months.
Expect about 253 mm of rain on roughly 26 days, which makes September a very wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 07 min on an average September day.
The nearest other city in this atlas is Port Dickson (103 km away). In September its highs average 29.1°C, 1.1°C cooler than Dumai, with 214 mm of rain.
Among the 200 cities listed in Indonesia, Dumai ranks joint 98th of 200 for the warmest September highs and 183rd of 200 for the driest September (rainfall, lowest first). The mean September high of those 200 cities is 30.1°C; Dumai is 0.1°C warmer than that mean.
From September to October, average highs fall by 0.3°C to 29.8°C, and monthly rainfall rises from 253 mm to 308 mm.
The annual picture
September 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
Dumai climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 28.9°C23.4°C | 23.4°C | 201 | 21.3 | 12.012 h |
| February | 29.7°C23.6°C | 23.6°C | 125 | 16.9 | 12.112 h |
| March | 30.2°C23.9°C | 23.9°C | 217 | 25.1 | 12.112 h |
| April | 30.3°C24.1°C | 24.1°C | 249 | 27.6 | 12.212 h |
| May | 30.5°C24.3°C | 24.3°C | 224 | 26.3 | 12.212 h |
| June | 30.5°C24.2°C | 24.2°C | 156 | 21.2 | 12.212 h |
| July | 30.3°C23.9°C | 23.9°C | 162 | 20.4 | 12.212 h |
| August | 30.3°C23.8°C | 23.8°C | 195 | 24.0 | 12.212 h |
| September, selected | 30.2°C23.6°C | 23.6°C | 253 | 26.1 | 12.112 h |
| October | 29.8°C23.6°C | 23.6°C | 308 | 28.2 | 12.112 h |
| November | 29.1°C23.4°C | 23.4°C | 387 | 28.5 | 12.012 h |
| December | 28.7°C23.4°C | 23.4°C | 343 | 27.7 | 12.012 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
September in nearby cities
- Port Dickson in SeptemberMalaysia · 103 kmHigh 29.1°C · Low 24.7°C · 214 mm rain
- Malacca in SeptemberMalaysia · 106 kmHigh 28.7°C · Low 25.0°C · 189 mm rain
- Sepang in SeptemberMalaysia · 119 kmHigh 28.9°C · Low 24.4°C · 189 mm rain
- Pekanbaru in SeptemberIndonesia · 128 kmHigh 30.3°C · Low 23.1°C · 195 mm rain
- Seremban in SeptemberMalaysia · 130 kmHigh 29.2°C · Low 23.6°C · 216 mm rain
- Muar in SeptemberMalaysia · 132 kmHigh 28.8°C · Low 24.7°C · 180 mm rain
- Cyberjaya in SeptemberMalaysia · 142 kmHigh 29.6°C · Low 23.3°C · 217 mm rain
- Puchong in SeptemberMalaysia · 149 kmHigh 30.0°C · Low 23.4°C · 129 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 Dumai) is explained once on the Dumai year overview and on the Sources, method and limits page.