Climate averages 1991–2020
Słupsk weather
in September.
A mild, moderately wet month: the 4th warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Słupsk: daytime highs average 17.1°C and nights cool to about 11.8°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 78 mm of rain on roughly 12 days, which makes September a moderately wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 47 min on an average September day.
The nearest other city in this atlas is Koszalin (63 km away). In September its highs average 17.4°C, about as warm as Słupsk, with 68 mm of rain.
Among the 60 cities listed in Poland, Słupsk ranks joint 58th of 60 for the warmest September highs and joint 57th of 60 for the driest September (rainfall, lowest first). The mean September high of those 60 cities is 18.3°C; Słupsk is 1.2°C cooler than that mean.
From September to October, average highs fall by 5.1°C to 12.0°C, and monthly rainfall rises from 78 mm to 80 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
Słupsk climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 2.1°C-1.4°C | -1.4°C | 59 | 12.1 | 7.98 h |
| February | 2.7°C-1.4°C | -1.4°C | 47 | 11.0 | 9.710 h |
| March | 5.7°C0.2°C | 0.2°C | 51 | 10.5 | 11.812 h |
| April | 11.0°C3.6°C | 3.6°C | 36 | 8.8 | 14.014 h |
| May | 15.4°C8.1°C | 8.1°C | 56 | 10.5 | 16.016 h |
| June | 18.6°C12.1°C | 12.1°C | 68 | 11.5 | 17.117 h |
| July | 21.0°C14.8°C | 14.8°C | 91 | 13.4 | 16.717 h |
| August | 21.1°C15.1°C | 15.1°C | 85 | 13.7 | 14.915 h |
| September, selected | 17.1°C11.8°C | 11.8°C | 78 | 12.3 | 12.813 h |
| October | 12.0°C7.6°C | 7.6°C | 80 | 13.6 | 10.611 h |
| November | 6.9°C3.5°C | 3.5°C | 65 | 13.2 | 8.69 h |
| December | 3.4°C0.2°C | 0.2°C | 66 | 13.5 | 7.47 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
- Koszalin in SeptemberPoland · 63 kmHigh 17.4°C · Low 11.5°C · 68 mm rain
- Gdynia in SeptemberPoland · 97 kmHigh 17.6°C · Low 11.6°C · 65 mm rain
- Gdańsk in SeptemberPoland · 106 kmHigh 17.8°C · Low 11.4°C · 51 mm rain
- Piła in SeptemberPoland · 147 kmHigh 18.2°C · Low 10.8°C · 51 mm rain
- Grudziądz in SeptemberPoland · 157 kmHigh 18.2°C · Low 10.9°C · 52 mm rain
- Elbląg in SeptemberPoland · 158 kmHigh 17.7°C · Low 11.6°C · 58 mm rain
- Bydgoszcz in SeptemberPoland · 162 kmHigh 18.4°C · Low 10.9°C · 50 mm rain
- Fordon in SeptemberPoland · 164 kmHigh 18.3°C · Low 11.0°C · 50 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 Słupsk) is explained once on the Słupsk year overview and on the Sources, method and limits page.