Finland Helsinki Weather in September (early autumn) — Climate Guide
September (early autumn) in Helsinki is Pleasant + cool
September (early autumn) is Pleasant + cool for Helsinki.
September is shoulder season transitioning to autumn. **Helsinki Design Week** (1st week) showcases Finnish design + 200+ events. Mushroom picking + autumn foliage in Helsinki's parks. Hotel rates dropping. Sauna culture begins seasonal swing back to peak.
Travel score
Helsinki September (early autumn) Weather Stats
Avg High
14°C
Avg Low
8°C
Rainy Days
12
67mm total
Sunshine
5h
Daily avg
Humidity
80%
Cool + damp
UV Index
3
Moderate
Wind
15 km/h
Gusts 32
Sea Temp
13°C
Avg water temp
Crowds
Moderate
At attractions
September (early autumn) Sunrise & Sunset
Air Quality
PM2.5
8 μg/m³
PM10
18 μg/m³
Status
Good
Feels-Like Temperature & Wind
Feels like
Daytime
13°C
Nighttime
7°C
Humidity and wind affect how the actual temperature feels.
Wind
15 km/h
Max gust 32 km/h
Activities Recommended for September (early autumn)
September (early autumn) Travel Pros & Cons
Pros
- Helsinki Design Week
- Hotel rates dropping
- Mushroom + autumn foliage
- Sauna season returning
Cons
- Days getting short
- Rainy + cooler
September (early autumn) Events & Festivals
- Helsinki Design Week (1st week)
- Mushroom picking season (forest)
Helsinki in September (early autumn) — Full Picture
September is shoulder season transitioning to autumn. **Helsinki Design Week** (1st week) showcases Finnish design + 200+ events. Mushroom picking + autumn foliage in Helsinki's parks. Hotel rates dropping. Sauna culture begins seasonal swing back to peak.
What to Wear & What to Pack
Early autumn — high 14°C, low 8°C. Light coat + sweater. Days getting shorter rapidly.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
7°C
-0.3°C
9/mo
Summer (Jun·Jul·Aug)
19.3°C
11.7°C
12.3/mo
Autumn (Sep·Oct·Nov)
Current8.3°C
3.7°C
13/mo
Winter (Dec·Jan·Feb)
-2.3°C
-8°C
10.7/mo
Helsinki Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| -3° | -9° | 11d·53mm | 1h | 85% | 0 | Quiet | Low season | |
| -3° | -10° | 9d·37mm | 3h | 84% | 0 | Quiet | Low season | |
| 1° | -6° | 9d·38mm | 4h | 80% | 2 | Quiet | Low season | |
| 7° | 0° | 9d·32mm | 6h | 70% | 4 | Quiet | Shoulder | |
| May (spring — best month) (Best) | 13° | 5° | 9d·39mm | 9h | 65% | 5 | Moderate | Shoulder |
| June (summer + white nights) (Best) | 18° | 10° | 11d·57mm | 10h | 65% | 6 | Busy | Peak |
| July (summer peak) (Best) | 21° | 13° | 13d·67mm | 9h | 70% | 6 | Very busy | Peak |
| 19° | 12° | 13d·79mm | 7h | 75% | 5 | Very busy | Peak | |
| 14° | 8° | 12d·67mm | 5h | 80% | 3 | Moderate | Shoulder | |
| 8° | 4° | 13d·74mm | 3h | 85% | 2 | Quiet | Low season | |
| 3° | -1° | 14d·73mm | 1h | 88% | 1 | Quiet | Low season | |
| -1° | -5° | 12d·56mm | 1h | 88% | 0 | Moderate | Shoulder |
View Other Months
Helsinki September (early autumn) Hotel Picks
Frequently Asked Questions
Is September (early autumn) a good time to visit Helsinki?
Helsinki in September (early autumn) is Pleasant + cool. Tourist crowds are moderate and flight/hotel prices are shoulder.
What's the average temperature in Helsinki in September (early autumn)?
Helsinki September (early autumn) averages a high of 14°C and a low of 8°C.
Does it rain much in Helsinki in September (early autumn)?
Helsinki September (early autumn) averages 67mm of rainfall over about 12 rainy days.
What should I wear in Helsinki in September (early autumn)?
Early autumn — high 14°C, low 8°C. Light coat + sweater. Days getting shorter rapidly.
What time are sunrise and sunset in Helsinki in September (early autumn)?
Helsinki September (early autumn) sunrise is 06:35 and sunset is 19:50, with 13h 15m of daylight.
What's the air quality like in Helsinki in September (early autumn)?
Helsinki September (early autumn) air quality (AQI) averages 30, rated Good. PM2.5 averages 8μg/m³.
What activities are recommended in Helsinki in September (early autumn)?
In September (early autumn), Helsinki is great for Helsinki Design Week, Saunas (becoming season), Mushroom picking + parks.
Is September (early autumn) peak season in Helsinki?
Helsinki September (early autumn) crowds are moderate and prices are shoulder. You can travel relatively comfortably without long queues.
Best Months to Visit Helsinki
View Other Months
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.