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December Weather in Isojoki, Finland

Last updated: August 23, 2025

In December, the average temperature in Isojoki, Finland hovers around -2°C (29°F), with fluctuations that can dip as low as -24°C (-11°F) or peak at a maximum of 5°C (42°F). During this month, expect 67 mm (2.6 in) of precipitation spread over about 14 days, contributing to an average humidity level of a notable 89%. Prepare for chilly, damp conditions as you experience this wintery period!

December Temperature in Isojoki

In December in Isojoki, the average temperature is -2°C (29°F), with maximums reaching 5°C (42°F) and minimums dropping as low as -24°C (-11°F). Travelers should be prepared for chilly conditions and dress in layers to stay warm while exploring the area's winter attractions.

December Weather in Isojoki: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Isojoki, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Isojoki, December typically has an average temperature of -2°C (29°F), with highs reaching up to 5°C (42°F) and lows dropping to around -24°C (-11°F).
JanFebMarAprMayJunJulAugSepOctNovDec252329384960635951423528
Data source: Temperature data for Isojoki generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Isojoki

In Isojoki in December, the precipitation amount is 67 mm (2.6 in) spread over 14 days.

December Precipitation Trends in Isojoki

The chart displays monthly precipitation patterns in Isojoki, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Isojoki, December typically receives around 67 mm (2.6 inches) of precipitation spread over approximately 14 days.
JanFebMarAprMayJunJulAugSepOctNovDec4346484647698711377806867
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Isojoki

In Isojoki in December humidity is 89%. With an average temperature of -2°C (29°F), this humidity feels like a suffocating fog that clings to your skin, making outdoor adventures less enjoyable and giving travel a heavy and oppressive feel.

December Average Humidity in Isojoki

This chart illustrates the average monthly humidity levels in Isojoki, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Isojoki is approximately 89%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec92%90%89%85%77%78%78%79%86%90%91%89%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Isojoki

In Isojoki in December, the maximum UV index is 1, which corresponds to a low Exposure Category. This means you have a time to burn of 45 minutes. For more details, you can check the Hourly UV Index in Isojoki.

Maximum UV Index Levels in Isojoki for December

The chart shows the monthly maximum UV Index (UVI) for Isojoki in December, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In December, the maximum UV index in Isojoki typically reaches 1, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec113456653211
Data source: Isojoki December UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How December Weather in Isojoki Compares to Other Months

Weather in Isojoki varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Isojoki, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Isojoki, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-4°C (26°F)43 mm (1.7 inches)92%low
February Weather-5°C (24°F)46 mm (1.8 inches)90%low
March Weather-2°C (29°F)48 mm (1.9 inches)89%moderate
April Weather3°C (38°F)46 mm (1.8 inches)85%moderate
May Weather9°C (49°F)47 mm (1.8 inches)77%moderate
June Weather16°C (61°F)69 mm (2.7 inches)78%high
July Weather17°C (63°F)87 mm (3.4 inches)78%high
August Weather15°C (60°F)113 mm (4.5 inches)79%moderate
September Weather11°C (51°F)77 mm (3.0 inches)86%moderate
October Weather6°C (42°F)80 mm (3.1 inches)90%low
November Weather2°C (35°F)68 mm (2.7 inches)91%low
December Weather-2°C (29°F)67 mm (2.6 inches)89%low

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