Ii, Finland experiences average highs of 6°C (43°F) and lows of 1°C (34°F) throughout the year. Rainfall is moderate, averaging about 11 rainy days per month. Average highs have warmed by 1.0°C (1.8°F) across the available records.
Ii, Finland Weather & Climate 2026
Monthly climate averages for Ii, Finland. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Jun 
Wetter season: Jul–Dec At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
3.5/10
Best: June, July, August
UV Index
2
Low
Temperature 6°C / 1°C
Feels Like 3°C / -2°C
Rainy Days 11
Rainfall 59 mm
Sunshine 7 h
Humidity 81%
Wind Speed 18 km/h
Dew Point 1°C
Snow Days 11 days
Frost Days 22 days
Hottest Month
20°C
July
Avg Low14°C
Rain12days
Coldest Month
-10°C
January
Avg High-6°C
Rain9days
Driest Month
8days
April
Avg High3°C
Avg Low-3°C
Windiest Month
20 km/h
January (Gusts 37)
Sea Temperature
0°C – 20°C
Warmest water: August (
20°C
)
Worst Time to Visit
Consider avoiding January, February, November, December due to very cold temperatures, frequent rain.
Sun Position
Sunrise 02:12
Daylight 22.3h
Sunset 00:29
Live conditions—
Ii on the map · live conditions
Ii, Finland
- Continent
- Europe
- Country
- Finland
- City
- Ii
- Population
- 9.8K
- Coordinates
- 65.32°, 25.37°
Seasonal Breakdown
Spring
Mar–May
Avg High 4°C
Avg Low -2°C
Rain 8 days/mo
Summer
Jun–Aug
Avg High 18°C
Avg Low 13°C
Rain 12 days/mo
3/3 best months
Autumn
Sep–Nov
Avg High 6°C
Avg Low 3°C
Rain 12 days/mo
Winter
Dec–Feb
Avg High -4°C
Avg Low -9°C
Rain 10 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: -6°C / -10°C . Feb: -5°C / -9°C . Mar: -2°C / -7°C . Apr: 3°C / -3°C . May: 10°C / 3°C . Jun: 17°C / 11°C . Jul: 20°C / 14°C . Aug: 18°C / 13°C . Sep: 13°C / 9°C . Oct: 6°C / 3°C . Nov: 1°C / -3°C . Dec: -2°C / -6°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 40 mm. Feb: 43 mm. Mar: 35 mm. Apr: 38 mm. May: 43 mm. Jun: 63 mm. Jul: 84 mm. Aug: 103 mm. Sep: 73 mm. Oct: 75 mm. Nov: 53 mm. Dec: 52 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 86%. Feb: 86%. Mar: 84%. Apr: 80%. May: 73%. Jun: 70%. Jul: 73%. Aug: 78%. Sep: 82%. Oct: 87%. Nov: 89%. Dec: 89%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 20 km/h . Feb: 19 km/h . Mar: 19 km/h . Apr: 17 km/h . May: 16 km/h . Jun: 17 km/h . Jul: 15 km/h . Aug: 18 km/h . Sep: 19 km/h . Oct: 19 km/h . Nov: 19 km/h . Dec: 19 km/h .
Sunshine
Sunshine
Sunshine: Jan: 1h. Feb: 3h. Mar: 7h. Apr: 10h. May: 13h. Jun: 15h. Jul: 13h. Aug: 11h. Sep: 6h. Oct: 3h. Nov: 1h. Dec: 0h.
Sea Temperature
Sea Temperatureswim
Line chart showing monthly sea temperature. Jan: 0°C . Feb: 0°C . Mar: 0°C . Apr: 0°C . May: 4°C . Jun: 15°C . Jul: 20°C . Aug: 20°C . Sep: 15°C . Oct: 7°C . Nov: 2°C . Dec: 0°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 0. Feb: UV 1. Mar: UV 2. Apr: UV 3. May: UV 4. Jun: UV 5. Jul: UV 5. Aug: UV 4. Sep: UV 2. Oct: UV 1. Nov: UV 0. Dec: UV 0.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow DaysSnowfall
Snow Days: Jan: 16 days. Feb: 15 days. Mar: 14 days. Apr: 9 days. May: 3 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 4 days. Nov: 11 days. Dec: 19 days.
Climate Trends
Average highs have warmed by 1.0°C (1.8°F) across the available records. Average rainfall has remained broadly steady.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 23°C | Jul · 20°C |
| Coldest month | Jan 2025 · -10°C | Jan · -10°C |
| Wettest month | Sep 2025 · 100 mm | Aug · 103 mm |
| Windiest month | Jan 2025 · 20 km/h | Jan · 20 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Poor April
Poor May
Fair June best
Good July best
Excellent August best
Good September
Fair October
Poor November
Poor December
Poor | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | -6°C / -10°C | -11°C / -15°C | 9days (40 mm) Wet | 0.8h Poor | 86% Very Muggy | 0.2 Low | Poor | View Details |
| February | -5°C / -9°C | -10°C / -14°C | 9days (43 mm) Wet | 2.6h Poor | 86% Very Muggy | 0.8 Low | Poor | View Details |
| March | -2°C / -7°C | -6°C / -12°C | 9days (35 mm) Wet | 6.5h Fair | 84% Humid | 2 Low | Poor | View Details |
| April | 3°C / -3°C | -1°C / -7°C | 8days (38 mm) Wet | 10h Excellent | 80% Humid | 3.2 Moderate | Poor | View Details |
| May | 10°C / 3°C | 7°C / 0°C | 8days (43 mm) Wet | 12.7h Excellent | 73% Muggy | 4.3 Moderate | Fair | View Details |
| June best | 17°C / 11°C | 15°C / 9°C | 9days (63 mm) Wet | 14.6h Excellent | 70% Muggy | 4.7 Moderate | Good | View Details |
| July best | 20°C / 14°C | 20°C / 13°C | 12days (84 mm) Wet | 13.3h Excellent | 73% Muggy | 4.5 Moderate | Excellent | View Details |
| August best | 18°C / 13°C | 17°C / 11°C | 14days (103 mm) Wet | 10.5h Excellent | 78% Humid | 3.7 Moderate | Good | View Details |
| September | 13°C / 9°C | 11°C / 6°C | 12days (73 mm) Wet | 6.2h Fair | 82% Humid | 2.2 Moderate | Fair | View Details |
| October | 6°C / 3°C | 2°C / -1°C | 13days (75 mm) Wet | 3.3h Poor | 87% Very Muggy | 0.9 Low | Poor | View Details |
| November | 1°C / -3°C | -4°C / -7°C | 12days (53 mm) Wet | 0.8h Poor | 89% Very Muggy | 0.3 Low | Poor | View Details |
| December | -2°C / -6°C | -7°C / -11°C | 12days (52 mm) Wet | 0.4h Poor | 89% Very Muggy | 0.1 Low | Poor | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Ii are June, July, August, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Ii, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Ii is July, with average daytime highs of 20°C (69°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Ii is January, with average overnight lows of -10°C (14°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Ii is August, averaging 103mm of precipitation across 14 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Ii runs through August, October, July, September, with the heaviest rainfall in August. Based on 10-year averages for Ii.
Ii receives approximately 82 sunshine hours per year. The sunniest month is June with around 15 hours. Based on climate data for Ii.
The least favorable months to visit Ii are January, February, November, December, primarily due to very cold temperatures, frequent rain. For the best conditions, consider June, July, August instead.
The annual average UV index in Ii is 2, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Ii is 81%, classified as humid. High humidity makes warm temperatures feel significantly hotter — lightweight, breathable clothing is recommended.
Sea temperatures in Summer average 7°C (45°F), which most swimmers will find too cold without a wetsuit.
Yes, Ii receives snow. Months with snowfall average 11 snow days and 19 cm (7 in) of accumulation, with about 22 frost days during winter.
Average wind speeds in Ii are 18 km/h (11 mph). The windiest month is January with peak winds reaching 20 km/h (12 mph) (gusts up to 37 km/h / 23 mph).
Ii averages 2 clear-sky days per month with overall cloud cover around 71%. The clearest skies occur in July.
The annual average dew point in Ii is 1°C (34°F), which feels dry and comfortable. Outdoor activities are comfortable year-round from a humidity standpoint.
Ii has a Warm-Summer Continental climate, classified as Dfb under the Köppen system. Continental climates experience extreme temperature ranges — hot summers and cold, snowy winters.
The 'feels like' temperature in Ii ranges from -2°C (28°F) to 3°C (37°F) on average. Wind chill makes winters feel noticeably colder than the actual temperature — layered clothing is recommended.
Yes, June is a great time to visit Ii. It earns a climate score of 7.3/10 with Good.
For June in Ii, pack Layered clothing, Light jacket, Umbrella, Comfortable walking shoes. With average highs of 17°C (62°F) and 9 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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