Climate averages 1991–2020
Brno weather
in September.
A mild, moderately wet month: the 4th 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 Brno: daytime highs average 19.5°C and nights cool to about 11.0°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 64 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 39 min on an average September day.
The nearest other city in this atlas is Olomouc (64 km away). In September its highs average 19.0°C, 0.5°C cooler than Brno, with 67 mm of rain.
Among the 12 cities listed in Czechia, Brno ranks 2nd of 12 for the warmest September highs and 6th of 12 for the driest September (rainfall, lowest first). The mean September high of those 12 cities is 18.8°C; Brno is 0.7°C warmer than that mean.
From September to October, average highs fall by 5.9°C to 13.6°C, and monthly rainfall falls from 64 mm to 44 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
Brno climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 1.9°C-3.7°C | -3.7°C | 33 | 8.8 | 8.79 h |
| February | 4.3°C-2.9°C | -2.9°C | 28 | 7.3 | 10.110 h |
| March | 8.9°C0.2°C | 0.2°C | 40 | 8.8 | 11.912 h |
| April | 14.8°C4.7°C | 4.7°C | 40 | 9.1 | 13.714 h |
| May | 19.2°C9.7°C | 9.7°C | 65 | 12.4 | 15.315 h |
| June | 22.8°C13.4°C | 13.4°C | 75 | 12.3 | 16.216 h |
| July | 25.0°C15.5°C | 15.5°C | 84 | 13.0 | 15.816 h |
| August | 24.9°C15.3°C | 15.3°C | 69 | 10.4 | 14.414 h |
| September, selected | 19.5°C11.0°C | 11.0°C | 64 | 9.5 | 12.713 h |
| October | 13.6°C6.4°C | 6.4°C | 44 | 8.9 | 10.811 h |
| November | 7.5°C2.3°C | 2.3°C | 41 | 9.0 | 9.29 h |
| December | 2.6°C-2.3°C | -2.3°C | 36 | 9.0 | 8.38 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
- Olomouc in SeptemberCzechia · 64 kmHigh 19.0°C · Low 10.4°C · 67 mm rain
- Zlín in SeptemberCzechia · 77 kmHigh 19.0°C · Low 10.8°C · 76 mm rain
- Vienna in SeptemberAustria · 111 kmHigh 20.3°C · Low 11.8°C · 71 mm rain
- Pardubice in SeptemberCzechia · 111 kmHigh 18.9°C · Low 10.4°C · 68 mm rain
- Bratislava in SeptemberSlovakia · 122 kmHigh 20.7°C · Low 12.0°C · 67 mm rain
- Hradec Králové in SeptemberCzechia · 126 kmHigh 18.7°C · Low 10.3°C · 59 mm rain
- Ostrava in SeptemberCzechia · 140 kmHigh 18.7°C · Low 10.4°C · 82 mm rain
- Nitra in SeptemberSlovakia · 146 kmHigh 21.0°C · Low 12.0°C · 60 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 Brno) is explained once on the Brno year overview and on the Sources, method and limits page.