Climate averages 1991–2020
Olsztyn weather
in September.
A mild, moderately wet month: the 5th warmest and the 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Olsztyn: daytime highs average 17.1°C and nights cool to about 10.1°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 59 mm of rain on roughly 10 days, which makes September a moderately wet month (the 8th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 46 min on an average September day.
The nearest other city in this atlas is Elbląg (82 km away). In September its highs average 17.7°C, 0.6°C warmer than Olsztyn, with 58 mm of rain.
Among the 60 cities listed in Poland, Olsztyn ranks joint 58th of 60 for the warmest September highs and joint 31st of 60 for the driest September (rainfall, lowest first). The mean September high of those 60 cities is 18.3°C; Olsztyn is 1.2°C cooler than that mean.
From September to October, average highs fall by 5.9°C to 11.1°C, and monthly rainfall falls from 59 mm to 50 mm.
The annual picture
September in context
Monthly precipitation
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
Olsztyn climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -0.4°C-4.6°C | -4.6°C | 43 | 10.8 | 8.18 h |
| February | 1.0°C-4.3°C | -4.3°C | 37 | 8.9 | 9.710 h |
| March | 5.4°C-1.8°C | -1.8°C | 43 | 10.3 | 11.812 h |
| April | 12.1°C2.7°C | 2.7°C | 41 | 9.7 | 14.014 h |
| May | 17.2°C7.8°C | 7.8°C | 64 | 12.2 | 15.916 h |
| June | 20.3°C11.6°C | 11.6°C | 70 | 12.3 | 17.017 h |
| July | 22.3°C14.0°C | 14.0°C | 86 | 13.2 | 16.517 h |
| August | 22.0°C13.9°C | 13.9°C | 66 | 11.4 | 14.815 h |
| September, selected | 17.1°C10.1°C | 10.1°C | 59 | 9.8 | 12.813 h |
| October | 11.1°C5.5°C | 5.5°C | 50 | 10.1 | 10.611 h |
| November | 5.3°C1.4°C | 1.4°C | 42 | 9.9 | 8.69 h |
| December | 1.2°C-2.5°C | -2.5°C | 45 | 10.4 | 7.58 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet 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
- Elbląg in SeptemberPoland · 82 kmHigh 17.7°C · Low 11.6°C · 58 mm rain
- Kaliningrad in SeptemberRussia · 103 kmHigh 17.7°C · Low 11.0°C · 59 mm rain
- Grudziądz in SeptemberPoland · 119 kmHigh 18.2°C · Low 10.9°C · 52 mm rain
- Gdańsk in SeptemberPoland · 136 kmHigh 17.8°C · Low 11.4°C · 51 mm rain
- Płock in SeptemberPoland · 147 kmHigh 18.3°C · Low 10.6°C · 51 mm rain
- Gdynia in SeptemberPoland · 152 kmHigh 17.6°C · Low 11.6°C · 65 mm rain
- Toruń in SeptemberPoland · 152 kmHigh 18.4°C · Low 10.9°C · 52 mm rain
- Włocławek in SeptemberPoland · 158 kmHigh 18.5°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 Olsztyn) is explained once on the Olsztyn year overview and on the Sources, method and limits page.