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December Weather in Willisau, Switzerland

Last updated: August 27, 2025

In December, the average temperature in Willisau, Switzerland is a chilly 1°C (35°F). Temperatures can dip as low as -7°C (20°F) and may reach a maximum of 12°C (53°F). Prepare for some wet days, as 152 mm (6.0 in) of precipitation can be expected over 19 days, with an average humidity of 90% creating a damp atmosphere.

December Temperature in Willisau

In December in Willisau, the average temperature is 1°C (35°F). Maximum can reach 12°C (53°F) and minimum can be as low as -7°C (20°F). Be prepared for chilly weather and dress warmly when exploring this destination during your visit.

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

The chart illustrates December temperature patterns in Willisau, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Willisau, December typically has an average temperature of 1°C (35°F), with highs reaching up to 12°C (53°F) and lows dropping to around -7°C (20°F).
JanFebMarAprMayJunJulAugSepOctNovDec323640465362646457493935
Data source: Temperature data for Willisau 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 Willisau

In Willisau in December, the precipitation amount is 152 mm (6.0 in) over a span of 19 days.

December Precipitation Trends in Willisau

The chart displays monthly precipitation patterns in Willisau, 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 Willisau, December typically receives around 152 mm (6.0 inches) of precipitation spread over approximately 19 days.
JanFebMarAprMayJunJulAugSepOctNovDec121961148815916016515710213180152
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Willisau

In Willisau in December humidity is 90%. With an average temperature of 1°C (35°F), this humidity feels like an icy blanket clinging to your skin, making travel uncomfortable and every breath a struggle against the damp chill.

December Average Humidity in Willisau

This chart illustrates the average monthly humidity levels in Willisau, 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 Willisau is approximately 90%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec92%89%87%84%80%82%83%80%83%90%89%90%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Willisau

In Willisau in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Willisau, you can visit Hourly UV Index in Willisau.

Maximum UV Index Levels in Willisau for December

The chart shows the monthly maximum UV Index (UVI) for Willisau 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 Willisau typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235689986422
Data source: Willisau 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 Willisau Compares to Other Months

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

This table compares monthly weather conditions in Willisau, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)120 mm (4.7 inches)92%low
February Weather2°C (36°F)96 mm (3.8 inches)89%moderate
March Weather5°C (40°F)114 mm (4.5 inches)87%moderate
April Weather8°C (47°F)88 mm (3.4 inches)84%high
May Weather12°C (53°F)159 mm (6.3 inches)80%very high
June Weather17°C (62°F)159 mm (6.3 inches)82%very high
July Weather18°C (65°F)165 mm (6.5 inches)83%very high
August Weather18°C (64°F)157 mm (6.2 inches)80%very high
September Weather14°C (57°F)102 mm (4.0 inches)83%high
October Weather10°C (49°F)131 mm (5.2 inches)90%moderate
November Weather4°C (40°F)80 mm (3.2 inches)88%low
December Weather1°C (35°F)152 mm (6.0 inches)90%low

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