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Brno in September: Weather, Average temperature and Climate

Planning a trip and want to know what the weather in Brno in September will be like? Take a look at our weather guide for Brno, based on historical data.
Check flight prices to Brno on Avionero:
September

Weather in Brno in September 2025

OK Weather
Mild
🌧️
Rainy
If you plan to visit Brno in September, the weather is typically alright, with an average high temperature of +20°C during the day and approximately 8 sunny days. Expect some rainy, though, as there are typically 14 rainy days in the month and around 60 mm of precipitation. The weather is changeable so you may have to pack for every eventuality. Search flights in one click on Avionero.

Average weather

☀️
+20°C
Avg. max. temperature
+1°C
Min.
+32°C
Max.
60 mm
Total precipitation
76%
Avg. humidity
2 m/s
Avg. wind
8 ☀️
Sunny Days
8 ⛅️
Cloudy
14 🌦
Rainy
Our opinion: Brno has OK weather in September.

Average temperature in Brno in September

Here are the expected maximum, average and minimum temperatures in Brno for September based on the historical data.
Last Year
Historical Data

Going from a maximum of +29°C during the day to a minimum of +10°C during the night, the temperature in September averages around +25°C.

The average maximum temperature goes up 0% by the end of the month, compared with the beginning of the month, from +22°C to +22°C.

Is Brno warm or cold in September?

Brno is typically mild in September.

Maximum temperatures go down compared to the previous month from +25°C to +20°C. The minimum temperature also goes down from +15°C to +11°C.

Pack a light jacket as it will be warm in the day and cool in the evenings.

Take a look at how September is compared to other months in Brno:

Climate in Brno in September

Brno weather looks like this, on average, in September and the surrounding months.
AugustSeptemberOctober
Avg. temperature
+25°C+20°C+14°C
Min. temperature
+4°C+1°C-5°C
Max. temperature
+36°C+32°C+27°C
Rainfall
78 mm60 mm41 mm
Wind
2 m/s2 m/s2 m/s
Humidity
70%76%82%
Air pressure
1015 HPa1016 HPa1018 HPa
Sunny days
986
Cloudy days
4812
Rainy days
161413
Snowy days
000

September typically has worse weather conditions compared to August. It’s getting colder in September. From +25°C in the day, the average maximum temperature lowers to +20°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 78 mm to 60 mm. Humidity rises from 70% to 76%. The average wind speed doesn’t change much during September, staying around 2 m/s. The days becoming less sunny, going from 9 sunny days in August to 8 in September.

October brings much the same weather, it remains ok.

Wind

Wind speed in Brno in September based on historical data.
Last Year
Historical Data

The average wind speed is 3 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.

The average wind speed in Brno is gradually increasing during September, going from 1 m/s to 3 m/s over the course of the month.

Rain

Amount of rainfall in mm during September in Brno based on historical data.
Last Year
Historical Data
Typically, there is a 27% chance of rain on an average day in September, with total rainfall of approximately 25 mm. The maximum amount of rainfall per day is around 5 mm, which is considered light rain. On average, there are about 8 rainy days during September, so prepare to bring an umbrella.
Here’s how September is compared with other months in the amount of precipitation, total mm:
Brno wettest month is July, where a typical day has a 55% chance of precipitation and 85 mm of rainfall per day. January, on the other hand, is the driest month with a mere 19% chance of precipitation and 17 mm of rainfall per day.

How was the weather last September in Brno?

This is the weather in Brno in September 2023:
1 September
☀️
+22°C
2 September
☀️
+25°C
3 September
☀️
+23°C
4 September
☀️
+23°C
5 September
☀️
+24°C
6 September
☀️
+27°C
7 September
☀️
+26°C
8 September
☀️
+27°C
9 September
☀️
+28°C
10 September
☀️
+28°C
11 September
☀️
+29°C
12 September
☀️
+29°C
13 September
☀️
+27°C
14 September
☁️
+24°C
15 September
☀️
+23°C
16 September
☀️
+25°C
17 September
☀️
+25°C
18 September
☀️
+26°C
19 September
☀️
+23°C
20 September
☀️
+24°C
21 September
☀️
+24°C
22 September
🌧️
+23°C
23 September
☀️
+19°C
24 September
☀️
+18°C
25 September
☀️
+23°C
26 September
☀️
+26°C
27 September
☀️
+27°C
28 September
☀️
+26°C
29 September
☀️
+26°C
30 September
☀️
+22°C
In September 2023 Brno had 28 sunny days, 1 cloudy days, and 1 rainy days. The average maximum temperature was +25°C, with an absolute maximum of +29°C and a minimum of +18°C. The average humidity was 73%, with a maximum of 100% and a minimum of 39%. The average wind speed was 3 m/s, with a maximum of 9 m/s and a minimum of 0 m/s.
Are you planning a trip in September?

Climate Change over Years

This is how Brno climate have been changing during last 43 years period.

The climate in Brno in September has not changed much over the last 43 years.

The average temperature was the lowest in 1996 (+11°C) and the highest in 2023 (+16°C). The driest year was 1983 with only 359 mm of rainfall, and the wettest year was 2021 with 1029 mm.

FAQ

Frequently asked questions about the weather in Brno in September:

Is September a good time to visit Brno?

It’s always a good time to visit Brno, but the weather is changeable in September, so plan a mix of indoor and outdoor activities and exploring, and pack for every eventuality.

Can you sunbathe in Brno in September?

September has mild temperatures in Brno. Not ideal for sunbathing, but still good for daytime outdoor activities, but plan for cool evenings. Pack a light jacket and shorts!

Is Brno rainy in September?

Brno is often rainy in September. You may get a bit damp when outside, so pack an umbrella, and maybe even a raincoat.

Is it sunny in Brno in September?

Usually, it’s not very sunny in Brno in September, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.

Other cities in Czech Republic

Check out the weather for other cities in Czech Republic.

Monthly weather in Brno

Source of the data

For this page, we’ve looked at the typical weather in Brno, based on historical hourly weather data from January 1, 1979, to December 31, 2023.

For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.