September could be a good time to visit Trondheim, as the weather is generally fine. The average high temperature is around +57°F, and there are typically 2 sunny days in September. However, expect about 21 rainy days, and total monthly rainfall of approximately 121 mm. The weather is changeable so pack for every eventuality. Search flightsin one click on Avionero.
Average weather
☀️
+57°F
Avg. max. temperature
+28°F
Min.
+77°F
Max.
121 mm
Total precipitation
79%
Avg. humidity
1 m/s
Avg. wind
2 ☀️
Sunny Days
7 ⛅️
Cloudy
21 🌦
Rainy
Our opinion: Trondheim has OK weather in September.
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Average temperature in Trondheim in September
Here are the expected maximum, average and minimum temperatures in Trondheim for September based on the historical data.
Last Year
Historical Data
The expected average maximum temperature in September is +61°F with a maximum of +73°F and a minimum of +37°F.
The average maximum temperature goes down 20% by the end of the month, compared with the beginning of the month, from +63°F to +55°F.
Is Trondheim warm or cold in September?
Trondheim is typically mild in September.
Maximum temperatures go down compared to the previous month from +64°F to +57°F. The minimum temperature also goes down from +50°F to +45°F.
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 Trondheim:
Water temperature in Trondheim in September
Water in Trondheim in September is Cold. It varies from +52°F to +60°F, with an average of +56°F.This is almost similar to the air temperature, which averages +57°F.
The water temperature in September is one of the warmest of the entire year:
The warmest water temperatures in Trondheim are reached in August, when the average sea temperature rises to +58°F. The coldest water temperatures are in March, with an average of +41°F.
Can you swim in Trondheim in September?
We would not recommend swimming in Trondheim in September, the water is very cold (+56°F on average). Consider swimming only if you are an experienced cold-water swimmer with proper gear.
🦭
Cold
Below +61°F
🏄♂️
Fresh
61°F - 70°F
🏊
Comfortable
70°F - 77°F
👙
Warm
77°F - 82°F
🔥
Very warm
+82°C and up
You will need a full-body wetsuit, cap, gloves, a warm change of clothes, and a hot drink ready for after your swim.
Climate in Trondheim in September
Trondheim weather looks like this, on average, in September and the surrounding months.
August
September
October
Avg. temperature
+64°F
+57°F
+48°F
Min. temperature
+36°F
+28°F
+10°F
Max. temperature
+86°F
+77°F
+72°F
Rainfall
124 mm
121 mm
92 mm
Wind
1 m/s
1 m/s
2 m/s
Avg. water temperature
+58°F
+56°F
+52°F
Humidity
78%
79%
80%
Air pressure
1010 HPa
1010 HPa
1008 HPa
Sunny days
1
2
2
Cloudy days
7
7
8
Rainy days
23
21
18
Snowy days
0
0
3
September weather is still as ok as in August.It’s getting colder in September. From +64°F in the day, the average maximum temperature lowers to +57°F.As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 124 mm to 121 mm.Humidity rises from 78% to 79%.The average wind speed doesn’t change much during September, staying around 1 m/s.The good news is there are likely to be more sunny days in September, from 1 to 2.
October brings much the same weather, it remains ok.
Wind speed in Trondheim in September based on historical data.
Last Year
Historical Data
The average wind speed is 1 m/s getting up to 2 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Trondheim is gradually increasing during September, going from 0 m/s to 0 m/s over the course of the month.
Rain
Amount of rainfall in mm during September in Trondheim based on historical data.
Last Year
Historical Data
Total precipitation in September is about 183 mm, with a 80% chance of rain on a typical day. The maximum amount of rainfall per day is around 25 mm, which is moderate rain.September is a pretty wet month with over 24 rainy days, so don’t forget to pack an umbrella, raincoat, and a pair of wellies.
September is one of the rainiest months in Trondheim, here is a comparison with other months, total mm:
Trondheim wettest month is August, where a typical day has a 74% chance of precipitation and 124 mm of rainfall per day. February, on the other hand, is the driest month with a mere 14% chance of precipitation and 38 mm of rainfall per day.
How was the weather last September in Trondheim?
This is the weather in Trondheim in September 2023:
1 September
☁️
+63°F
2 September
☁️
+61°F
3 September
🌧️
+57°F
4 September
🌧️
+63°F
5 September
🌧️
+56°F
6 September
☁️
+63°F
7 September
☁️
+65°F
8 September
☁️
+67°F
9 September
☀️
+74°F
10 September
☁️
+60°F
11 September
☁️
+68°F
12 September
🌧️
+57°F
13 September
🌧️
+54°F
14 September
☁️
+57°F
15 September
☁️
+62°F
16 September
☁️
+54°F
17 September
☁️
+59°F
18 September
☁️
+61°F
19 September
🌧️
+61°F
20 September
🌧️
+60°F
21 September
🌧️
+57°F
22 September
🌧️
+56°F
23 September
☁️
+57°F
24 September
☁️
+60°F
25 September
🌧️
+68°F
26 September
☁️
+66°F
27 September
☁️
+60°F
28 September
☁️
+64°F
29 September
🌧️
+57°F
30 September
🌧️
+55°F
In September 2023 Trondheim had 1 sunny days, 17 cloudy days, and 12 rainy days. The average maximum temperature was +61°F, with an absolute maximum of +73°F and a minimum of +54°F. The average humidity was 84%, with a maximum of 100% and a minimum of 59%. The average wind speed was 1 m/s, with a maximum of 5 m/s and a minimum of 0 m/s.
Are you planning a trip in September?
Climate Change Over the Years
This is how Trondheim climate has changed over the last 43 years.
The climate in Trondheim in September has not changed that much over the last 43 years.
The average temperature was the lowest in 1981 (+45°F) and the highest in 2014 (+52°F). The driest year was 2002 with only 617 mm of rainfall, and the wettest year was 2007 with 1311 mm.
FAQ
Frequently asked questions about the weather in Trondheim in September:
Is September a good time to visit Trondheim?
It’s always a good time to visit Trondheim, 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 Trondheim in September?
September has mild temperatures in Trondheim. Not ideal for sunbathing, but still good for daytime outdoor activities, but plan for cool evenings. Pack a light jacket and shorts!
Can you swim in Trondheim in September?
Swimming in Trondheim in September is challenging and not recommended for inexperienced swimmers or without proper equipment and preparation.
Is Trondheim rainy in September?
Trondheim 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 Trondheim in September?
Usually, it’s not very sunny in Trondheim in September, often it’s pretty cloudy. Pack for any eventuality; layering can help reduce the number of bulky items needed.
For this page, we’ve looked at the typical weather in Trondheim, 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.
