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December Weather in St Helena, Australia

Last updated: August 22, 2025

In December, the average temperature in St Helena, Australia is a pleasant 18°C (65°F). However, be prepared for a range, as temperatures can dip to a chilly 8°C (46°F) or soar to a sweltering 43°C (109°F). This month typically brings about 74 mm (2.9 in) of precipitation over 7 days, with an average humidity of 50%—perfect for enjoying the crisp air or planning your next adventure!

December Temperature in St Helena

In December in St Helena, the average temperature is 18°C (65°F). Maximums can reach 43°C (109°F), while minimums can be as low as 8°C (46°F). Travelers should be prepared for a wide temperature range, making it essential to pack both lightweight clothing for the heat and layers for cooler evenings.

December Weather in St Helena: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in St Helena, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In St Helena, December typically has an average temperature of 18°C (65°F), with highs reaching up to 43°C (109°F) and lows dropping to around 8°C (46°F).
JanFebMarAprMayJunJulAugSepOctNovDec696766605450495054586265
Data source: Temperature data for St Helena 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 St Helena

In St Helena in December, the precipitation amount is 74 mm (2.9 in) over a period of 7 days.

December Precipitation Trends in St Helena

The chart displays monthly precipitation patterns in St Helena, 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 St Helena, December typically receives around 74 mm (2.9 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec424440515754465864745874
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in St Helena

In St Helena in December humidity is 50%. With an average temperature of 18°C (65°F), this humidity feels like a comfortable embrace, making it pleasant for traveling as you can enjoy outdoor activities without feeling overly sticky or fatigued.

December Average Humidity in St Helena

This chart illustrates the average monthly humidity levels in St Helena, 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 St Helena is approximately 50%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec43%49%60%71%79%82%83%79%72%61%59%50%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in St Helena

In St Helena in December, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in St Helena, you can check here.

Maximum UV Index Levels in St Helena for December

The chart shows the monthly maximum UV Index (UVI) for St Helena 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 St Helena typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec14121174335791214
Data source: St Helena 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 St Helena Compares to Other Months

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

This table compares monthly weather conditions in St Helena, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather21°C (70°F)42 mm (1.6 inches)43%extreme
February Weather19°C (67°F)44 mm (1.7 inches)49%extreme
March Weather19°C (66°F)40 mm (1.6 inches)60%extreme
April Weather15°C (60°F)51 mm (2.0 inches)71%high
May Weather12°C (54°F)57 mm (2.2 inches)79%moderate
June Weather10°C (50°F)54 mm (2.1 inches)81%moderate
July Weather10°C (49°F)46 mm (1.8 inches)83%moderate
August Weather10°C (50°F)58 mm (2.3 inches)79%moderate
September Weather12°C (54°F)64 mm (2.5 inches)72%high
October Weather14°C (58°F)74 mm (2.9 inches)61%very high
November Weather17°C (62°F)58 mm (2.3 inches)59%extreme
December Weather18°C (65°F)74 mm (2.9 inches)50%extreme

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