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December Weather in Harriston, United States

Last updated: June 24, 2025

In December, the average temperature in Harriston, United States hovers around 4°C (39°F). During this time, you can expect temperatures to range from a chilly -13°C (10°F) to a comfortable 21°C (70°F). Be prepared for some rain, as 84 mm (3.3 in) of precipitation is likely over 8 days, coupled with a relatively high average humidity of 85%.

December Temperature in Harriston

In December in Harriston, the average temperature is 4°C (39°F), with maximums reaching up to 21°C (70°F) and minimums dropping as low as -13°C (10°F). Visitors should be prepared for a wide range of temperatures, making it essential to pack accordingly for both warmth and comfort.

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

The chart illustrates December temperature patterns in Harriston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Harriston, December typically has an average temperature of 4°C (39°F), with highs reaching up to 21°C (70°F) and lows dropping to around -13°C (10°F).
JanFebMarAprMayJunJulAugSepOctNovDec354045556472777469594439
Data source: Temperature data for Harriston 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 Harriston

In Harriston in December, the precipitation amount is 84 mm (3.3 in) spread over 8 days.

December Precipitation Trends in Harriston

The chart displays monthly precipitation patterns in Harriston, 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 Harriston, December typically receives around 84 mm (3.3 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec60876710811089591081021067684
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Harriston

In Harriston in December, humidity is 85%. With an average temperature of 4°C (39°F), this humidity feels like a damp chill that seeps into your bones, making traveling uncomfortable and requiring extra layers to ward off the cold and moisture.

December Average Humidity in Harriston

This chart illustrates the average monthly humidity levels in Harriston, 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 Harriston is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%84%78%79%70%59%68%80%87%85%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Harriston

In Harriston in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Harriston, you can check the information here.

Maximum UV Index Levels in Harriston for December

The chart shows the monthly maximum UV Index (UVI) for Harriston 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 Harriston typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579111010109753
Data source: Harriston 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 Harriston Compares to Other Months

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

This table compares monthly weather conditions in Harriston, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (35°F)60 mm (2.4 inches)86%moderate
February Weather5°C (40°F)87 mm (3.4 inches)86%moderate
March Weather7°C (46°F)67 mm (2.6 inches)86%high
April Weather13°C (55°F)108 mm (4.2 inches)84%very high
May Weather18°C (65°F)110 mm (4.3 inches)78%extreme
June Weather22°C (72°F)89 mm (3.5 inches)79%very high
July Weather25°C (77°F)59 mm (2.3 inches)70%very high
August Weather24°C (75°F)108 mm (4.2 inches)59%very high
September Weather21°C (69°F)102 mm (4.0 inches)68%very high
October Weather15°C (60°F)106 mm (4.2 inches)80%high
November Weather7°C (44°F)76 mm (3.0 inches)86%moderate
December Weather4°C (39°F)84 mm (3.3 inches)85%moderate

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