September weather forecast
Rijeka, Croatia

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The colorful and hilly seaside scenic city of Rijeka in Croatia
The colorful and hilly seaside scenic city of Rijeka in Croatia

Weather in September

Rijeka's September weather typically announces the advent of autumn. The average high temperature begins to cool from the summer peak, and the nights gradually grow colder. Daily sunshine hours start to decrease, yet Rijeka maintains its scenic charm. September also witnesses a rise in rainfall compared to August, with the month recording 157mm (6.18") of precipitation. Despite these changes, the Adriatic sea remains warm, favoring late summer swims.

Temperature

In September, the average high-temperature in Rijeka, Croatia, marginally decreases from a moderately hot 28.1°C (82.6°F) in August to a still warm 23.5°C (74.3°F). An average nighttime temperature of 14.9°C (58.8°F) is observed in Rijeka during September.

Humidity

In Rijeka, the average relative humidity in September is 63.7%.

Rainfall

In Rijeka, in September, during 10.6 rainfall days, 157mm (6.18") of precipitation is typically accumulated. Throughout the year, in Rijeka, there are 130.3 rainfall days, and 1552mm (61.1") of precipitation is accumulated.

Snowfall

April through November are months without snowfall in Rijeka, Croatia.

Sea temperature

In Rijeka, in September, the average water temperature is 23.4°C (74.1°F).
Note: Factoring in a person's dislike for cold, combined with conditions like sunshine, wind, and temperature, a dip in 23.4°C (74.1°F) waters might be satisfying. (It is worth noting that the Olympic swimming waters are maintained between 25°C (77°F) and 28°C (82.4°F).)

Daylight

In Rijeka, the average length of the day in September is 12h and 32min.
On the first day of September in Rijeka, Croatia, sunrise is at 06:24 and sunset at 19:39. On the last day of the month, sunrise is at 06:59 and sunset at 18:44 CEST.

Sunshine

In Rijeka, the average sunshine in September is 6.7h.

UV index

In Rijeka, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for average individuals.
Note: A maximum UV index of 5 in September translates into the following recommendations:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades. Take caution! The UV rays from the Sun gain strength from sand and water reflections.

Frequently asked questions

What is the usual temperature for Rijeka in September?

September temperatures in Rijeka vary between a high-temperature of 23.5°C (74.3°F) and a low-temperature of 14.9°C (58.8°F). The average heat index (a.k.a. 'felt air temperature', 'feels like'), which represents the influence of relative humidity on air temperature, in August is evaluated at 29°C (84.2°F).

What is the average humidity in September in Rijeka?

In Rijeka, the average relative humidity in September is 63.7%.

How many days does it rain in September in Rijeka?

In Rijeka, during September, the rain falls for 10.6 days and regularly aggregates up to 157mm (6.18") of precipitation.

When it does not snow in Rijeka?

In Rijeka, Croatia, snow does not fall in April through November.

What is the sea temperature in September in Rijeka?

In Rijeka, Croatia, in September, the average water temperature is 23.4°C (74.1°F). Depending on a person's sensitivity to cold, with regards to sunshine, wind, and air temperature, a quick swim in 23.4°C (74.1°F) water may be enjoyable.

How many hours of daylight does Rijeka have in September?

In Rijeka, the average day length in September is 12h and 32min.

What time are sunrise and sunset in September in Rijeka?

On the first day of September, sunrise is at 06:24 and sunset at 19:39. On the last day of the month, sunrise is at 06:59 and sunset at 18:44 CEST.

How long on average sun shines in September in Rijeka?

In Rijeka, Croatia, the average sunshine duration in September is 6.7h.

What is the UV index intensity in September in Rijeka?

In Rijeka, Croatia, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average UV index

Average temperature in September
Rijeka, Croatia

Average temperature in September - Rijeka, Croatia
  • Average high temperature in September: 23.5°C

The warmest month (with the highest average high temperature) is August (28.1°C).
The month with the lowest average high temperature is January (9.1°C).

  • Average low temperature in September: 14.9°C

The months with the highest average low temperature are July and August (18.6°C).
The coldest month (with the lowest average low temperature) is January (2.9°C).

Average humidity in September
Rijeka, Croatia

Average humidity in September - Rijeka, Croatia
  • Average humidity in September: 63.7%

The month with the highest relative humidity is October (67.4%).
The month with the lowest relative humidity is August (56%).

Average rainfall in September
Rijeka, Croatia

Average rainfall in September - Rijeka, Croatia
  • Average rainfall in September: 156.5mm

The wettest month (with the highest rainfall) is October (203.9mm).
The driest month (with the least rainfall) is July (70.1mm).

Average rainfall days in September
Rijeka, Croatia

Average rainfall days in September - Rijeka, Croatia
  • Average rainfall days in September: 10.6 days

The month with the highest number of rainy days is April (12.6 days).
The month with the least rainy days is February (8.5 days).

Average snowfall days in September
Rijeka, Croatia

Average snowfall days in September - Rijeka, Croatia
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (0.8 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).

Average sea temperature in September
Rijeka, Croatia

Average sea temperature in September - Rijeka, Croatia
  • Average sea temperature in September: 23.4°C

The best month for swimming (with the highest average sea temperature) is August (24.9°C).
The coldest month (with the lowest average sea temperature) is February (10.7°C).

Average daylight in September /
Average sunshine in September
Rijeka, Croatia

Average daylight in September / Average sunshine in September - Rijeka, Croatia
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in September: 6h and 4min

The month with the most sunshine is July (Average sunshine: 9h and 36min).
The month with the least sunshine is December (Average sunshine: 3h and 12min).

Average UV index in September
Rijeka, Croatia

Average UV index in September - Rijeka, Croatia
  • Average UV index in September: 5

The months with the highest UV index are June and July (UV index 8).
The months with the lowest UV index are January and December (UV index 1).

Rijeka, Croatia

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