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December Weather in Summit, United States

Last updated: June 24, 2025

In December, the average temperature in Summit, United States hovers around 12°C (54°F). However, temperatures can range dramatically, dipping as low as -7°C (20°F) and peaking at a warm 28°C (82°F). Expect approximately 147 mm (5.8 in) of precipitation spread over 12 days, contributing to an average humidity level of 88%.

December Temperature in Summit

In December in Summit, the average temperature is 12°C (54°F), with maximums reaching 28°C (82°F) and minimums dropping as low as -7°C (20°F). It's advisable to pack layers to accommodate the wide temperature range during your travels.

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

The chart illustrates December temperature patterns in Summit, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Summit, December typically has an average temperature of 12°C (54°F), with highs reaching up to 28°C (82°F) and lows dropping to around -7°C (20°F).
JanFebMarAprMayJunJulAugSepOctNovDec505662657479818078705753
Data source: Temperature data for Summit 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 Summit

In Summit in December, the precipitation amount is 147 mm (5.8 in) over a span of 12 days.

December Precipitation Trends in Summit

The chart displays monthly precipitation patterns in Summit, 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 Summit, December typically receives around 147 mm (5.8 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec12512511814517415115017511110790147
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Summit

In Summit in December, humidity is 88%. With an average temperature of 12°C (54°F), this humidity feels like a thick, damp blanket, making traveling a bit uncomfortable as the air clings to your skin, causing you to sweat even in cooler weather.

December Average Humidity in Summit

This chart illustrates the average monthly humidity levels in Summit, 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 Summit is approximately 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec83%83%80%81%81%78%79%79%79%77%85%88%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Summit

In Summit in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Summit for better planning.

Maximum UV Index Levels in Summit for December

The chart shows the monthly maximum UV Index (UVI) for Summit 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 Summit typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec589111112121110864
Data source: Summit 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 Summit Compares to Other Months

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

This table compares monthly weather conditions in Summit, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (50°F)125 mm (4.9 inches)83%moderate
February Weather13°C (56°F)125 mm (4.9 inches)83%very high
March Weather17°C (62°F)118 mm (4.6 inches)80%very high
April Weather19°C (66°F)144 mm (5.7 inches)81%extreme
May Weather23°C (74°F)173 mm (6.8 inches)81%extreme
June Weather26°C (79°F)151 mm (5.9 inches)78%extreme
July Weather27°C (81°F)150 mm (5.9 inches)79%extreme
August Weather27°C (80°F)175 mm (6.9 inches)79%extreme
September Weather26°C (78°F)111 mm (4.4 inches)79%very high
October Weather21°C (70°F)107 mm (4.2 inches)77%very high
November Weather14°C (57°F)90 mm (3.5 inches)85%high
December Weather12°C (54°F)147 mm (5.8 inches)88%moderate

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