Kotka Weather in September
September in Kotka brings moderate temperatures around 16°C (61°F) during the day, dropping to 10°C (50°F) at night, with quite a bit of rainfall expected, averaging around 68 mm (2.7 in) for the month.
Rainfall in Kotka in September
You can expect rain on roughly 16 days based on historical data, averaging 68 mm (2.7 in) for the month. Rain falls on many days this month, but usually in relatively small amounts. A light waterproof is more useful than a heavy umbrella.
Temperature in Kotka in September
September in Kotka sees highs of 16°C (61°F) and lows of 10°C (50°F) overnight. The difference between afternoon and evening temperatures is usually noticeable. Nights drop to 10°C (50°F). Cold nights like these are actually great for sleeping well, as long as you have a warm enough duvet.If you prefer dry days with pleasant temperatures, July and August typically offer the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Finland, check out our Kotka's climate page.
Kotka Temperature in September
Min Temperature
10°C (50°F)
Max Temperature
16°C (61°F)
Chance of Rain
53%
Precipitation
68 mm (2.7 in)
Rainy days
16 days
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Kotka typically drop from around 16°C (61°F) at the start of September to approximately 12°C (54°F) by the end. Nights are cool, with lows typically ranging from 7°C (45°F) to 12°C (54°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 Kotka in September
Browse day-by-day weather records for Kotka spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Kotka historical weather extremes in September
According to our 49 years of weather records for Kotka, the following extremes were recorded between 1976 and 2025.
- The hottest September day on record in Kotka reached 25°C (77°F) (September 4, 2024).
- Kotka experienced its chilliest September day on September 26, 1986, reaching only 5°C (41°F).
- The lowest overnight temperature recorded in September was -4°C (25°F) (September 30, 1993).
- The wettest September day on record brought 25 mm (1 in) of precipitation to Kotka (September 14, 2023).
Best Places in Finland in September
Find out more about the weather in Finland and which places have the best travel conditions in this month. See all of Finland in September →
perfect weather
pleasant
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What to Wear in Kotka in September
Pack for changing conditions in Kotka in September. Bring a mix of short and long sleeves, a warm layer like a hoodie or light jacket, and comfortable pants. The key is being able to add or remove layers as the days goes by. Rain gear is recommended, you can expect wet weather on multiple days.What To Do in Kotka 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 Finland, check out our Kotka's climate page.
See the full Kotka climate overview or explore weather in Finland.
