Climate averages 1991–2020
Pematangsiantar weather
in September.
A warm, very wet month: the 7th warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Pematangsiantar: daytime highs average 27.5°C and nights cool to about 20.6°C. By daytime temperature it is the 7th warmest of the 12 months.
Expect about 361 mm of rain on roughly 29 days, which makes September a very wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 08 min on an average September day.
The nearest other city in this atlas is Tebingtinggi (42 km away). In September its highs average 29.4°C, 1.9°C warmer than Pematangsiantar, with 238 mm of rain.
Among the 200 cities listed in Indonesia, Pematangsiantar ranks joint 179th of 200 for the warmest September highs and 198th of 200 for the driest September (rainfall, lowest first). The mean September high of those 200 cities is 30.1°C; Pematangsiantar is 2.6°C cooler than that mean.
From September to October, average highs fall by 0.4°C to 27.1°C, and monthly rainfall rises from 361 mm to 375 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
Pematangsiantar climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 26.6°C20.2°C | 20.2°C | 240 | 27.9 | 12.012 h |
| February | 27.1°C20.2°C | 20.2°C | 190 | 24.3 | 12.012 h |
| March | 27.8°C20.7°C | 20.7°C | 217 | 26.4 | 12.112 h |
| April | 27.9°C21.0°C | 21.0°C | 249 | 28.6 | 12.212 h |
| May | 28.2°C21.3°C | 21.3°C | 265 | 29.2 | 12.312 h |
| June | 28.3°C21.1°C | 21.1°C | 231 | 27.1 | 12.312 h |
| July | 28.1°C20.8°C | 20.8°C | 236 | 26.7 | 12.312 h |
| August | 27.9°C20.7°C | 20.7°C | 274 | 28.7 | 12.212 h |
| September, selected | 27.5°C20.6°C | 20.6°C | 361 | 29.4 | 12.112 h |
| October | 27.1°C20.6°C | 20.6°C | 375 | 30.2 | 12.112 h |
| November | 26.6°C20.6°C | 20.6°C | 351 | 29.4 | 12.012 h |
| December | 26.3°C20.5°C | 20.5°C | 315 | 29.6 | 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
- Tebingtinggi in SeptemberIndonesia · 42 kmHigh 29.4°C · Low 23.4°C · 238 mm rain
- Kisaran in SeptemberIndonesia · 61 kmHigh 29.8°C · Low 23.3°C · 278 mm rain
- Kabanjahe in SeptemberIndonesia · 66 kmHigh 25.0°C · Low 17.2°C · 247 mm rain
- Perbaungan in SeptemberIndonesia · 69 kmHigh 29.4°C · Low 23.8°C · 219 mm rain
- Percut in SeptemberIndonesia · 77 kmHigh 29.4°C · Low 23.2°C · 324 mm rain
- Tanjungbalai in SeptemberIndonesia · 81 kmHigh 29.5°C · Low 24.2°C · 282 mm rain
- Medan in SeptemberIndonesia · 82 kmHigh 29.5°C · Low 22.5°C · 353 mm rain
- Sunggal in SeptemberIndonesia · 85 kmHigh 29.6°C · Low 22.2°C · 306 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 Pematangsiantar) is explained once on the Pematangsiantar year overview and on the Sources, method and limits page.