Climate averages 1991–2020
Nusantara weather
in September.
A hot, wet month: the joint 2nd warmest and the 2nd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Nusantara: daytime highs average 29.9°C and nights cool to about 23.4°C. By daytime temperature it is the joint 2nd warmest of the 12 months.
Expect about 155 mm of rain on roughly 19 days, which makes September a wet month (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 06 min on an average September day.
The nearest other city in this atlas is Balikpapan (35 km away). In September its highs average 28.2°C, 1.7°C cooler than Nusantara, with 109 mm of rain.
Among the 200 cities listed in Indonesia, Nusantara ranks joint 107th of 200 for the warmest September highs and joint 155th of 200 for the driest September (rainfall, lowest first). The mean September high of those 200 cities is 30.1°C; Nusantara is 0.2°C cooler than that mean.
From September to October, average highs rise by 0.3°C to 30.1°C, and monthly rainfall rises from 155 mm to 222 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
Nusantara climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 29.5°C23.3°C | 23.3°C | 323 | 27.9 | 12.212 h |
| February | 29.8°C23.4°C | 23.4°C | 288 | 24.5 | 12.112 h |
| March | 29.9°C23.5°C | 23.5°C | 349 | 28.5 | 12.112 h |
| April | 29.8°C23.7°C | 23.7°C | 356 | 27.9 | 12.112 h |
| May | 29.5°C23.8°C | 23.8°C | 270 | 28.2 | 12.112 h |
| June | 29.0°C23.5°C | 23.5°C | 221 | 25.4 | 12.112 h |
| July | 28.7°C23.2°C | 23.2°C | 181 | 23.5 | 12.112 h |
| August | 29.2°C23.2°C | 23.2°C | 142 | 20.3 | 12.112 h |
| September, selected | 29.9°C23.4°C | 23.4°C | 155 | 18.9 | 12.112 h |
| October | 30.1°C23.5°C | 23.5°C | 222 | 24.0 | 12.112 h |
| November | 29.7°C23.5°C | 23.5°C | 308 | 28.4 | 12.212 h |
| December | 29.5°C23.5°C | 23.5°C | 349 | 29.4 | 12.212 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
- Balikpapan in SeptemberIndonesia · 35 kmHigh 28.2°C · Low 24.6°C · 109 mm rain
- Loa Janan in SeptemberIndonesia · 61 kmHigh 30.6°C · Low 23.6°C · 167 mm rain
- Samarinda in SeptemberIndonesia · 72 kmHigh 30.6°C · Low 23.4°C · 173 mm rain
- Bontang in SeptemberIndonesia · 150 kmHigh 29.6°C · Low 24.4°C · 130 mm rain
- Palangkaraya in SeptemberIndonesia · 339 kmHigh 31.9°C · Low 23.3°C · 113 mm rain
- Martapura in SeptemberIndonesia · 340 kmHigh 31.8°C · Low 23.4°C · 74 mm rain
- Banjarbaru in SeptemberIndonesia · 344 kmHigh 31.9°C · Low 23.0°C · 74 mm rain
- Banjarmasin in SeptemberIndonesia · 351 kmHigh 31.6°C · Low 23.8°C · 69 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 Nusantara) is explained once on the Nusantara year overview and on the Sources, method and limits page.