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December Weather in Waterloo, United States

Last updated: June 24, 2025

In Waterloo, United States, the average temperature in December hovers around 0°C (33°F). While it can dip to a minimum of -16°C (4°F), temperatures may occasionally reach a comfortable maximum of 18°C (65°F). Prepare for 101 mm (4.0 in) of precipitation spread over 17 days, contributing to an average humidity of 86%. Stay warm and dry!

December Temperature in Waterloo

In December in Waterloo, the average temperature is 0°C (33°F). Maximum temperatures can reach 18°C (65°F), while minimum temperatures can drop as low as -16°C (4°F). Be sure to pack layers to stay comfortable during your travels!

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

The chart illustrates December temperature patterns in Waterloo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Waterloo, December typically has an average temperature of 0°C (33°F), with highs reaching up to 18°C (65°F) and lows dropping to around -16°C (4°F).
JanFebMarAprMayJunJulAugSepOctNovDec272935465867737164544032
Data source: Temperature data for Waterloo 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 Waterloo

In Waterloo in December, the total precipitation amount is 101 mm (4.0 in) over the course of 17 days.

December Precipitation Trends in Waterloo

The chart displays monthly precipitation patterns in Waterloo, 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 Waterloo, December typically receives around 101 mm (4.0 inches) of precipitation spread over approximately 17 days.
JanFebMarAprMayJunJulAugSepOctNovDec898881119116861531088215497101
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Waterloo

In Waterloo in December humidity is 86%. With an average temperature of 0°C (33°F), this humidity feels like a damp chill that permeates your clothes, making traveling uncomfortable and necessitating warm, layered clothing to stay dry and cozy.

December Average Humidity in Waterloo

This chart illustrates the average monthly humidity levels in Waterloo, 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 Waterloo is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%90%87%88%82%79%78%76%78%84%89%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Waterloo

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

Maximum UV Index Levels in Waterloo for December

The chart shows the monthly maximum UV Index (UVI) for Waterloo 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 Waterloo typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24681010997632
Data source: Waterloo 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 Waterloo Compares to Other Months

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

This table compares monthly weather conditions in Waterloo, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)89 mm (3.5 inches)90%low
February Weather-2°C (29°F)88 mm (3.5 inches)90%moderate
March Weather2°C (35°F)81 mm (3.2 inches)87%high
April Weather8°C (46°F)119 mm (4.7 inches)88%very high
May Weather14°C (58°F)116 mm (4.6 inches)82%very high
June Weather20°C (67°F)86 mm (3.4 inches)79%very high
July Weather23°C (73°F)153 mm (6.0 inches)78%very high
August Weather22°C (72°F)108 mm (4.3 inches)76%very high
September Weather18°C (65°F)82 mm (3.2 inches)78%high
October Weather12°C (55°F)154 mm (6.1 inches)84%high
November Weather4°C (40°F)97 mm (3.8 inches)89%moderate
December Weather0°C (33°F)101 mm (4.0 inches)86%low

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