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December Weather in Upper Montclair, United States

Last updated: June 24, 2025

In December, the average temperature in Upper Montclair, United States hovers around 3°C (38°F). You can expect a minimum temperature that dips to -11°C (12°F) and a maximum that reaches up to 18°C (64°F). During this month, rainfall amounts to 108 mm (4.3 in) over approximately 10 days, with an average humidity of 80%, creating a brisk yet damp atmosphere.

December Temperature in Upper Montclair

In December in Upper Montclair, the average temperature is 3°C (38°F), where the maximum can reach 18°C (64°F) and the minimum can drop as low as -11°C (12°F). It's essential to pack layers and prepare for a wide range of temperatures if you're planning to travel during this time.

December Weather in Upper Montclair: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Upper Montclair, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Upper Montclair, December typically has an average temperature of 3°C (38°F), with highs reaching up to 18°C (64°F) and lows dropping to around -11°C (12°F).
JanFebMarAprMayJunJulAugSepOctNovDec333641526271777569594537
Data source: Temperature data for Upper Montclair 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 Upper Montclair

In Upper Montclair in December, the total precipitation amount is 108 mm (4.3 in) spread over a duration of 10 days.

December Precipitation Trends in Upper Montclair

The chart displays monthly precipitation patterns in Upper Montclair, 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 Upper Montclair, December typically receives around 108 mm (4.3 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec691031001161239714612910013484108
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Upper Montclair

In Upper Montclair in December, humidity is 80%. With an average temperature of 3°C (38°F), this humidity feels like a chilly dampness that clings to your skin, making traveling uncomfortable and forcing you to bundle up just to step outside.

December Average Humidity in Upper Montclair

This chart illustrates the average monthly humidity levels in Upper Montclair, 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 Upper Montclair is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Upper Montclair

In Upper Montclair 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 Upper Montclair, you can visit Hourly UV Index in Upper Montclair.

Maximum UV Index Levels in Upper Montclair for December

The chart shows the monthly maximum UV Index (UVI) for Upper Montclair 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 Upper Montclair typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356810101098642
Data source: Upper Montclair 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 Upper Montclair Compares to Other Months

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

This table compares monthly weather conditions in Upper Montclair, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (33°F)69 mm (2.7 inches)84%moderate
February Weather2°C (36°F)103 mm (4.1 inches)82%moderate
March Weather5°C (42°F)100 mm (3.9 inches)81%high
April Weather11°C (52°F)116 mm (4.6 inches)78%very high
May Weather17°C (62°F)123 mm (4.8 inches)69%very high
June Weather22°C (72°F)97 mm (3.8 inches)69%very high
July Weather25°C (78°F)146 mm (5.7 inches)62%very high
August Weather24°C (76°F)129 mm (5.1 inches)65%very high
September Weather21°C (70°F)100 mm (3.9 inches)68%very high
October Weather15°C (60°F)134 mm (5.3 inches)74%high
November Weather7°C (45°F)84 mm (3.3 inches)82%moderate
December Weather3°C (38°F)108 mm (4.3 inches)80%low

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