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Rijeka in September: Weather, Average temperature and Climate

Discover the weather for Rijeka in September and if it’s a good time to travel (based on historical data).
Check flight prices to Rijeka on Avionero:
September

Weather in Rijeka in September 2025

Good Weather
Warm
☀️
Sunny
🌊
Comfortable water
Weather for Rijeka in September is typically good with an average maximum temperature of +24°C during the day, and approximately 11 sunny days monthly. Typically, there are about 11 rainy days with the total average precipitation that falls in September around 221 mm. Expect good weather and pack accordingly to enjoy the outdoors. Search flights in one click on Avionero.

Average weather

☀️
+24°C
Avg. max. temperature
+9°C
Min.
+33°C
Max.
221 mm
Total precipitation
67%
Avg. humidity
2 m/s
Avg. wind
11 ☀️
Sunny Days
5 ⛅️
Cloudy
11 🌦
Rainy
Our opinion: Rijeka has good weather in September.

Average temperature in Rijeka in September

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

The expected average maximum temperature in September is +26°C with a maximum of +30°C and a minimum of +15°C.

The average maximum temperature goes up 7% by the end of the month, compared with the beginning of the month, from +26°C to +27°C.

Is Rijeka warm or cold in September?

Rijeka is typically warm in September.

Maximum temperatures go down compared to the previous month from +29°C to +24°C. The minimum temperature also goes down from +20°C to +16°C.

It’s generally warm, but pack a long-sleeve shirt for evenings.

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

Water temperature in Rijeka in September

Water in Rijeka in September is Comfortable. It varies from +20°C to +26°C, with an average of +23°C. This is almost similar to the air temperature, which averages +24°C.

The water temperature in September is one of the warmest of the entire year:

The warmest water temperatures in Rijeka are reached in August, when the average sea temperature rises to +24°C. The coldest water temperatures are in February, with an average of +11°C.

Can you swim in Rijeka in September?

The water in Rijeka in September is pretty comfortable (+23°C in average). Ideal for swimming, especially in outdoor pools and open water. Suitable for recreational and casual swimmers.
🦭
Cold
Below +16°C
🏄‍♂️
Fresh
16°C - 21°C
🏊
Comfortable
21°C - 25°C
👙
Warm
25°C - 28°C
🔥
Very warm
+28°C and up
Don’t forget a large beach towel or two for drying off.

Climate in Rijeka in September

Rijeka weather looks like this, on average, in September and the surrounding months.
AugustSeptemberOctober
Avg. temperature
+29°C+24°C+19°C
Min. temperature
+11°C+9°C+2°C
Max. temperature
+39°C+33°C+28°C
Rainfall
131 mm221 mm261 mm
Wind
1 m/s2 m/s2 m/s
Avg. water temperature
+24°C+23°C+19°C
Humidity
60%67%72%
Air pressure
1013 HPa1015 HPa1017 HPa
Sunny days
131110
Cloudy days
355
Rainy days
101114
Snowy days
000

September weather is still as good as in August. It’s getting colder in September. From +29°C in the day, the average maximum temperature lowers to +24°C. Prepare for more rain. Average rainfall goes from 131 mm to 221 mm. Humidity rises from 60% to 67%. Winds are stronger in comparison to August, going up from 1 m/s to 2 m/s on average. The days becoming less sunny, going from 13 sunny days in August to 11 in September.

October brings much the same weather, it remains good.

Wind

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

The average wind speed is 3 m/s getting up to 5 m/s which is a light breeze; barely moving the tree leaves.

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

Rain

Amount of rainfall in mm during September in Rijeka based on historical data.
Last Year
Historical Data
Total precipitation in September is about 187 mm, with a 30% chance of rain on a typical day. The maximum amount of rainfall per day is around 62 mm, which is considered heavy rain. On average, there are about 9 rainy days during September, so prepare to bring an umbrella.
September is one of the rainiest months in Rijeka, here is a comparison with other months, total mm:
Rijeka wettest month is November, where a typical day has a 47% chance of precipitation and 280 mm of rainfall per day. July, on the other hand, is the driest month with a mere 32% chance of precipitation and 98 mm of rainfall per day.

How was the weather last September in Rijeka?

This is the weather in Rijeka in September 2023:
1 September
🌧️
+26°C
2 September
☀️
+28°C
3 September
☀️
+29°C
4 September
☀️
+26°C
5 September
☀️
+25°C
6 September
☀️
+28°C
7 September
☀️
+28°C
8 September
☀️
+29°C
9 September
☀️
+29°C
10 September
☀️
+30°C
11 September
☀️
+28°C
12 September
☀️
+28°C
13 September
☀️
+25°C
14 September
☀️
+24°C
15 September
☀️
+25°C
16 September
☀️
+26°C
17 September
☀️
+25°C
18 September
☀️
+25°C
19 September
🌧️
+24°C
20 September
☀️
+25°C
21 September
🌧️
+22°C
22 September
🌧️
+24°C
23 September
🌧️
+21°C
24 September
🌧️
+17°C
25 September
☁️
+21°C
26 September
☀️
+26°C
27 September
☀️
+27°C
28 September
☀️
+26°C
29 September
☀️
+27°C
30 September
☀️
+27°C
In September 2023 Rijeka had 23 sunny days, 1 cloudy days, and 6 rainy days. The average maximum temperature was +26°C, with an absolute maximum of +30°C and a minimum of +17°C. The average humidity was 78%, with a maximum of 100% and a minimum of 50%. The average wind speed was 3 m/s, with a maximum of 10 m/s and a minimum of 0 m/s.
Are you planning a trip in September?

Climate Change over Years

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

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

The average temperature was the lowest in 1980 (+16°C) and the highest in 2011 (+20°C). The driest year was 2003 with only 1149 mm of rainfall, and the wettest year was 2019 with 4603 mm.

FAQ

Frequently asked questions about the weather in Rijeka in September:

Is September a good time to visit Rijeka?

September is a really good time to go to Rijeka. The weather is nice so plan your packing around outdoor activities and exploring. Check out other good time to visit Rijeka.

Can you sunbathe in Rijeka in September?

September is warm in Rijeka. You may enjoy some beach or pool time in the day, but pack something a tad warmer for the evening.

Can you swim in Rijeka in September?

Yes, the water temperature in Rijeka in September is considered moderate and enjoyable for most people, averaging around +23°C.

Is Rijeka rainy in September?

Rijeka 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 Rijeka in September?

The amount of sunny days in Rijeka during September varies; prepare for a mix of clouds and sun.

Other cities in Croatia

Check out the weather for other cities in Croatia.

Monthly weather in Rijeka

Source of the data

For this page, we’ve looked at the typical weather in Rijeka, 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.