Monthly climate guide
Białystok weather in September
Expect mild weather in Białystok in September: afternoons reach about 20°C (67°F), while nights drop to around 9°C (49°F). Around 55 mm of rain falls over the month (some rain), and skies are often cloudy. Daytime highs are 5°C cooler than August and 7°C warmer than October.
What stands out in September
- Just 330 km apart, but Białystok runs about 2°C warmer than Gdańsk this month.
- Seasonally, September counts as early autumn in Białystok.
- It cools down fast from here: October is about 7°C cooler.
Avg high
20°C
67°F
Avg low
9°C
49°F
Rainfall
55 mm
some rain
Humidity
75%
relative
Sky
63%
cloud · often cloudy
Białystok weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | -2°C / 28°F | -7°C / 19°F | 43 mm | 95% | 90% |
| February | 0°C / 32°F | -6°C / 21°F | 35 mm | 93% | 84% |
| March | 6°C / 44°F | -2°C / 28°F | 38 mm | 85% | 72% |
| April | 13°C / 56°F | 2°C / 36°F | 44 mm | 79% | 60% |
| May | 19°C / 66°F | 8°C / 46°F | 75 mm | 77% | 61% |
| June | 23°C / 73°F | 12°C / 54°F | 69 mm | 74% | 61% |
| July | 24°C / 76°F | 14°C / 57°F | 99 mm | 73% | 66% |
| August | 25°C / 77°F | 14°C / 57°F | 66 mm | 69% | 59% |
| September | 20°C / 67°F | 9°C / 49°F | 55 mm | 75% | 63% |
| October | 12°C / 54°F | 4°C / 39°F | 58 mm | 84% | 71% |
| November | 5°C / 42°F | 1°C / 33°F | 41 mm | 93% | 85% |
| December | 1°C / 34°F | -3°C / 26°F | 50 mm | 95% | 84% |
What to pack for September
- T-shirts plus a light layer for the evening
- Comfortable trainers or sandals for long walks
- A small travel umbrella, just in case
Is September a good time to visit Białystok?
Compare the months in the chart above to find your ideal window.
Best time to visit Białystok →Other Poland cities in September
Cite or embed this data
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Białystok weather in September. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/poland/bialystok/september
<a href="https://weathercompare.eu/weather/poland/bialystok/september">Białystok weather in September</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/poland/bialystok" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="Białystok weather in September"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/poland/bialystok/september">Białystok weather in September</a> – WeatherCompare</p>
Białystok in September: quick answers
Is September a good time to visit Białystok?
Yes. September is one of the best months for Białystok, with highs around 20°C and about 55 mm of rain.
How warm is Białystok in September?
Average highs are about 20°C (67°F) and average lows about 9°C (49°F), based on 10 years of daily data.
Does it rain a lot in Białystok in September?
Białystok typically gets around 55 mm of rain in September — some rain.
Figures are long-term averages for the area around Białystok (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.