Naantali Weather in September
Naantali in September averages 16°C (61°F) during the day and 9°C (48°F) at night. Keep in mind that quite a bit of rainfall is expected this month.
Rainfall in Naantali in September
Typically, you can expect about 18 days of rain this month, with 66 mm (2.6 in) on average. Rain is frequent but mostly light this month, with brief showers more common than heavy downpours.
Temperature in Naantali in September
September in Naantali brings moderate temperatures, with highs of 16°C (61°F) and nights around 9°C (48°F). Temperatures can feel cooler in the morning and evening, so layering is often the best approach. With overnight lows of 9°C (48°F), nights are cold. The cold air does make for deep, comfortable sleep if you have enough blankets.
Sunshine in Naantali in September
The area enjoys a balanced 154 hours of sunlight, ensuring it's neither too overcast nor too sunny.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 Naantali's climate page.
Naantali Temperature in September
Min Temperature
9°C (48°F)
Max Temperature
16°C (61°F)
Chance of Rain
60%
Precipitation
66 mm (2.6 in)
Rainy days
18 days
Sunshine
154 hours *
Percentage Sunshine
*
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Naantali typically drop from around 17°C (63°F) at the start of September to approximately 12°C (54°F) by the end. Nights are cool, with lows typically ranging from 5°C (41°F) to 11°C (52°F).
Average temperatures in September
Historical weather for Naantali in September
Browse day-by-day weather records for Naantali spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Naantali historical weather extremes in September
Based on weather observations in Naantali between 1976 and 2025, these are the recorded extremes during September.
- On September 5, 2024, temperatures climbed to 26°C (79°F), marking the warmest September day on record.
- The lowest daytime temperature in September was 2°C (36°F), recorded on September 30, 1997.
- The coldest night in September in Naantali was on September 30, 1976, with a minimum of -6°C (21°F).
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 Naantali in September
For Naantali in September, you'll want flexible clothing. It's wise to pack cotton shirts, comfortable shorts, and a pair of jeans for cooler evenings. A light sweater or jacket is useful for air-conditioned spaces (like buses) or unexpected cool moments. Rain is likely on several days, so bring a good rain jacket. Bring sunglasses since you'll have some sunny periods throughout the monthWhat To Do in Naantali 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 Naantali's climate page.
See the full Naantali climate overview or explore weather in Finland.
