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December Weather in Herculaneum, United States

Last updated: June 24, 2025

In Herculaneum, United States, the average temperature in December hovers around 4°C (40°F). You can expect temperatures to range from a brisk -15°C (4°F) to a warm 24°C (76°F). Precipitation typically measures 62 mm (2.5 in) over the course of about 7 days, and the air is characterized by an average humidity of 86%.

December Temperature in Herculaneum

In December in Herculaneum, the average temperature is 4°C (40°F). Maximum temperatures can reach 24°C (76°F), while minimums can drop as low as -15°C (4°F). Travelers should be prepared for a wide range of temperatures and pack accordingly.

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

The chart illustrates December temperature patterns in Herculaneum, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Herculaneum, December typically has an average temperature of 4°C (40°F), with highs reaching up to 24°C (76°F) and lows dropping to around -15°C (4°F).
JanFebMarAprMayJunJulAugSepOctNovDec333648556776797672594540
Data source: Temperature data for Herculaneum 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 Herculaneum

In Herculaneum in December, the precipitation amount is 62 mm (2.5 in) over a period of 7 days.

December Precipitation Trends in Herculaneum

The chart displays monthly precipitation patterns in Herculaneum, 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 Herculaneum, December typically receives around 62 mm (2.5 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec77841321371438889124691047162
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Herculaneum

In Herculaneum in December humidity is 86%. With an average temperature of 4°C (40°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities uncomfortable and travel cumbersome as you navigate through a thick, heavy air that clings to your skin.

December Average Humidity in Herculaneum

This chart illustrates the average monthly humidity levels in Herculaneum, 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 Herculaneum is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%80%80%80%82%83%81%80%76%76%85%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Herculaneum

In Herculaneum 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 Herculaneum, you can check the information here.

Maximum UV Index Levels in Herculaneum for December

The chart shows the monthly maximum UV Index (UVI) for Herculaneum 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 Herculaneum typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3579101110109753
Data source: Herculaneum 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 Herculaneum Compares to Other Months

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

This table compares monthly weather conditions in Herculaneum, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)77 mm (3.0 inches)82%moderate
February Weather2°C (37°F)84 mm (3.3 inches)80%moderate
March Weather9°C (48°F)132 mm (5.2 inches)80%high
April Weather13°C (56°F)137 mm (5.4 inches)80%very high
May Weather19°C (67°F)143 mm (5.6 inches)82%very high
June Weather24°C (76°F)88 mm (3.5 inches)83%extreme
July Weather26°C (80°F)89 mm (3.5 inches)81%very high
August Weather25°C (76°F)124 mm (4.9 inches)80%very high
September Weather22°C (72°F)68 mm (2.7 inches)76%very high
October Weather15°C (59°F)104 mm (4.1 inches)76%high
November Weather7°C (45°F)71 mm (2.8 inches)85%moderate
December Weather4°C (40°F)62 mm (2.5 inches)86%moderate

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