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December Weather in Islesboro, United States

Last updated: June 24, 2025

In December, the average temperature in Islesboro, United States hovers around 0°C (33°F). Expect chilly conditions, with a minimum dipping to -18°C (0°F) and a maximum reaching 13°C (55°F). Prepare for moisture, as precipitation typically totals 160 mm (6.3 in) over 12 days, accompanied by an average humidity level of 84%.

December Temperature in Islesboro

In December in Islesboro, the average temperature is 0°C (33°F). The maximum can reach 13°C (55°F), and the minimum can be as low as -18°C (0°F). Travelers should be prepared for chilly conditions and dress in layers to stay comfortable during their visit.

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

The chart illustrates December temperature patterns in Islesboro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Islesboro, December typically has an average temperature of 0°C (33°F), with highs reaching up to 13°C (55°F) and lows dropping to around -18°C (0°F).
JanFebMarAprMayJunJulAugSepOctNovDec282932414957636561534233
Data source: Temperature data for Islesboro 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 Islesboro

In Islesboro in December, the precipitation amount is 160 mm (6.3 in) over a span of 12 days.

December Precipitation Trends in Islesboro

The chart displays monthly precipitation patterns in Islesboro, 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 Islesboro, December typically receives around 160 mm (6.3 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec11210889169114871009099169145160
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Islesboro

In Islesboro in December humidity is 84%. With average temperature 0°C (33°F), this humidity feels like a damp chill that seeps into your bones, making outdoor adventures less enjoyable and travel plans challenging.

December Average Humidity in Islesboro

This chart illustrates the average monthly humidity levels in Islesboro, 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 Islesboro is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%85%81%76%74%74%74%77%82%85%84%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Islesboro

In Islesboro 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 Islesboro, you can visit Hourly UV Index in Islesboro.

Maximum UV Index Levels in Islesboro for December

The chart shows the monthly maximum UV Index (UVI) for Islesboro 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 Islesboro typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2457910987532
Data source: Islesboro 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 Islesboro Compares to Other Months

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

This table compares monthly weather conditions in Islesboro, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)112 mm (4.4 inches)88%low
February Weather-2°C (29°F)108 mm (4.2 inches)88%moderate
March Weather0°C (33°F)89 mm (3.5 inches)85%moderate
April Weather5°C (41°F)169 mm (6.7 inches)81%high
May Weather9°C (49°F)114 mm (4.5 inches)76%very high
June Weather14°C (58°F)87 mm (3.4 inches)74%very high
July Weather17°C (63°F)100 mm (3.9 inches)74%very high
August Weather18°C (65°F)90 mm (3.5 inches)74%very high
September Weather16°C (61°F)99 mm (3.9 inches)77%high
October Weather12°C (54°F)169 mm (6.6 inches)82%moderate
November Weather6°C (42°F)145 mm (5.7 inches)85%moderate
December Weather0°C (33°F)160 mm (6.3 inches)84%low

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