Trondheim Weather in September
September in Trondheim averages 16°C (61°F) during the day and 7°C (45°F) at night. It is the wettest month of the year, with 120 mm (4.7 in) of rainfall on average, so waterproof gear is a must.
Rainfall in Trondheim in September
Given that this is the rainiest month, it's wise to carry an umbrella to stay dry during unexpected showers. Looking at the last 30 years, the data shows about 24 days with rain, averaging 120 mm (4.7 in) for the month. Rain falls regularly this month and can be quite heavy when it does. Showers can be substantial, so waterproof gear is a good idea.
Temperature in Trondheim in September
If you're visiting Trondheim in September, expect highs of 16°C (61°F) and overnight lows around 7°C (45°F). Conditions are often most pleasant around the middle of the day. Nights fall to 7°C (45°F), which is cold enough to feel it indoors too. A good thick duvet makes all the difference for a comfortable night's sleep.
Sunshine in Trondheim in September
The area enjoys a moderate level of sunlight, with around 132 hours. It's a good balance between sunny and cloudy days.If your ideal day consists of dry skies and pleasant temperatures, July typically offers the best circumstances for Trondheim.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Norway, check out our Trondheim's climate page.
Trondheim Temperature in September
Min Temperature
7°C (45°F)
Max Temperature
16°C (61°F)
Chance of Rain
80%
Precipitation
120 mm (4.7 in)
Rainy days
24 days
Humidity
82% *
Sunshine
132 hours *
Percentage Sunshine
*
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Trondheim typically drop from around 16°C (61°F) at the start of September to approximately 12°C (54°F) by the end. Nights are cold, with lows typically ranging from 5°C (41°F) to 9°C (48°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Trondheim in September
Browse day-by-day weather records for Trondheim spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Trondheim historical weather extremes in September
Based on weather observations in Trondheim between 1976 and 2025, these are the recorded extremes during September.
- The warmest day in September was on September 3, 1999, with a maximum of 26°C (79°F).
- Trondheim experienced its chilliest September day on September 28, 2024, reaching only 5°C (41°F).
- The lowest overnight temperature recorded in September was -3°C (27°F) (September 28, 1976).
Best Places in Norway in September
Find out more about the weather in Norway and which places have the best travel conditions in this month. See all of Norway in September →
perfect weather
pleasant
tolerable
unpleasant
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What to Wear in Trondheim in September
The weather can be unpredictable in September, so pack clothes you can easily mix and match. You could bring jeans, other long pants, and a few t-shirts. A light jacket or light sweater will be pleasant for the cooler moments. High rain levels are expected, so pack waterproof gear and an umbrella or poncho. Bring sunglasses since you'll have some sunny periods throughout the monthWhat To Do in Trondheim in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Norway, check out our Trondheim's climate page.
Temperature Rainfall Sunshine Humidity
See the full Trondheim climate overview or explore weather in Norway.
