Climate & Weather in Helsinki

Good to Know

• Summer temperatures rarely exceed 25°C (77°F) — expect cool days even in peak season June-August, so pack layers
• White nights (nearly continuous daylight May-August) mean less sleep time and require blackout curtains if you're light-sensitive
• Winter darkness is severe: December sees only ~1 hour of sun per day and ~6 hours of daylight total; this affects mood and activity planning
• Snowfall is variable year-to-year; recent winters have been milder than historical averages (2019–2020 saw almost no snow)
• Spring is the driest season (~100mm precipitation over three months), making late April–May ideal if you want dry weather and longer days without extreme heat
• Sea temperature ranges 0°C (32°F) in winter to ~16°C (61°F) in summer — never warm for casual swimming, but ice swimming (with sauna) is a local winter tradition
• Precipitation is frequent but often light; ~182 rainy/snowy days per year, so waterproof jacket is essential gear