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December Weather in Round Rock, United States

Last updated: June 24, 2025

In December, the average temperature in Round Rock, United States hovers around 1°C (34°F), with minimums dipping to -15°C (6°F) and swinging to maximums of 17°C (62°F). Expect 22 mm (0.8 in) of precipitation spread over 5 days, accompanied by a notable average humidity of 85%.

December Temperature in Round Rock

In December in Round Rock, the average temperature is 1°C (34°F), with a maximum that can reach 17°C (62°F) and a minimum that can drop as low as -15°C (6°F). Travelers should be prepared for a wide range of temperatures and dress accordingly for both chilly and milder conditions.

December Weather in Round Rock: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Round Rock, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Round Rock, December typically has an average temperature of 1°C (34°F), with highs reaching up to 17°C (62°F) and lows dropping to around -15°C (6°F).
JanFebMarAprMayJunJulAugSepOctNovDec323846556376797869544433
Data source: Temperature data for Round Rock 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 Round Rock

In Round Rock in December, the precipitation amount is 22 mm (0.8 in) over the course of 5 days.

December Precipitation Trends in Round Rock

The chart displays monthly precipitation patterns in Round Rock, 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 Round Rock, December typically receives around 22 mm (0.8 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec2222321014314512211022
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Round Rock

In Round Rock in December, humidity is 85%. With an average temperature of 1°C (34°F), this humidity feels like a biting chill that seeps into your bones, making outdoor travel uncomfortable and urging you to seek warmth indoors rather than explore the surroundings.

December Average Humidity in Round Rock

This chart illustrates the average monthly humidity levels in Round Rock, 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 Round Rock is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%86%76%69%53%40%36%44%59%74%83%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Round Rock

In Round Rock 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 Round Rock for better planning.

Maximum UV Index Levels in Round Rock for December

The chart shows the monthly maximum UV Index (UVI) for Round Rock 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 Round Rock typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec479111213131211864
Data source: Round Rock 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 Round Rock Compares to Other Months

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

This table compares monthly weather conditions in Round Rock, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)22 mm (0.9 inches)85%moderate
February Weather3°C (38°F)22 mm (0.9 inches)86%high
March Weather8°C (46°F)31 mm (1.2 inches)76%very high
April Weather13°C (55°F)10 mm (0.4 inches)69%extreme
May Weather17°C (63°F)14 mm (0.6 inches)53%extreme
June Weather24°C (76°F)3 mm (0.1 inches)40%extreme
July Weather26°C (80°F)14 mm (0.5 inches)36%extreme
August Weather25°C (78°F)4 mm (0.2 inches)44%extreme
September Weather21°C (69°F)12 mm (0.5 inches)59%extreme
October Weather12°C (54°F)21 mm (0.8 inches)74%very high
November Weather7°C (44°F)10 mm (0.4 inches)83%high
December Weather1°C (34°F)22 mm (0.8 inches)85%moderate

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