Porvoo Weather in September
Porvoo in September averages 17°C (63°F) during the day and 8°C (46°F) at night. Keep in mind that quite a bit of rainfall is expected this month.
Rainfall in Porvoo in September
Historically, September sees about 16 days of rain, with a monthly average of 60 mm (2.4 in). Rain is frequent but mostly light this month, with brief showers more common than heavy downpours.
Temperature in Porvoo in September
September in Porvoo sees highs of 17°C (63°F) and lows of 8°C (46°F) overnight. The difference between afternoon and evening temperatures is usually noticeable. With overnight lows of 8°C (46°F), nights are cold. The cold air does make for deep, comfortable sleep if you have enough blankets.
Sunshine in Porvoo in September
With about 151 hours of sunshine, the area enjoys a nice balance of sun and overcast, creating a pleasant environment.If you prefer dry days with pleasant temperatures, June, 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 Porvoo's climate page.
Porvoo Temperature in September
Min Temperature
8°C (46°F)
Max Temperature
17°C (63°F)
Chance of Rain
54%
Precipitation
60 mm (2.4 in)
Rainy days
16 days
Humidity
84% *
Sunshine
151 hours *
Percentage Sunshine
*
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Porvoo typically drop from around 17°C (63°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 10°C (50°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 Porvoo in September
Browse day-by-day weather records for Porvoo spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Porvoo historical weather extremes in September
According to our 49 years of weather records for Porvoo, the following extremes were recorded between 1976 and 2025.
- On September 5, 2024, temperatures climbed to 27°C (81°F), marking the warmest September day on record.
- Porvoo experienced its chilliest September day on September 23, 2014, reaching only 5°C (41°F).
- The lowest overnight temperature recorded in September was -6°C (21°F) (September 30, 1993).
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
tolerable
unpleasant
poor
What to Wear in Porvoo in September
Pleasant temperatures in September mean you can pack light but flexibel pieces. Think cotton t-shirts, comfortable walking shorts, and one warmer layer for evenings. A light sweater or denim jacket works well. Rain gear is recommended, you can expect wet weather on multiple days. Bring sunglasses since you'll have some sunny periods throughout the monthWhat To Do in Porvoo 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 Porvoo's climate page.
Temperature Rainfall Sunshine Humidity
See the full Porvoo climate overview or explore weather in Finland.
