December weather forecast
Georgetown, Saint Helena, Ascension and Tristan da Cunha

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Weather in December

The last month of the year, December, sees a substantial change in the weather of Georgetown, Saint Helena, Ascension and Tristan da Cunha. With an average wind speed of 23.9km/h (14.9mph), December proves to be the least windy month of the year. The temperature shift towards the warmer spectrum is indicative of the arrival of peak summer. Sunshine stretches to 5.9 hours per day, marking the return of longer sunny days. With this, the season turns a full circle from a warm and wet start to the year, back to the long, lovely days of island summer to round off December.

Temperature

Georgetown records an average high-temperature of a still moderately hot 24.4°C (75.9°F) as December arrives, nearly mirroring the previous month's climate. Georgetown reports an average low temperature of 23.7°C (74.7°F) in December, a minor decrease from the day's highs.

Humidity

In December, the average relative humidity is 80%.

Rainfall

In Georgetown, Saint Helena, Ascension and Tristan da Cunha, in December, it is raining for 12.1 days, with typically 11mm (0.43") of accumulated precipitation. In Georgetown, during the entire year, the rain falls for 166.5 days and collects up to 168mm (6.61") of precipitation.

Daylight

With an average of 12h and 36min of daylight, December has the longest days of the year.
On the first day of December in Georgetown, sunrise is at 06:30 and sunset at 19:03. On the last day of the month, sunrise is at 06:43 and sunset at 19:18 GMT.

Sunshine

In Georgetown, the average sunshine in December is 5.9h.

UV index

The average daily maximum UV index in December in Georgetown is 6. A UV Index reading of 6 to 7 represents a high threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum high UV index of 6 in December translates into the following recommendations:
Adopt measures and apply sun safety strategies. Shielding from skin and eye damage is necessary. The Sun emits the most powerful UV radiation between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes.
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Frequently asked questions

What are the temperatures in Georgetown in December?

In December, the average high-temperature and low-temperature in Georgetown, Saint Helena, Ascension and Tristan da Cunha, are 24.4°C (75.9°F) and 23.7°C (74.7°F) respectively. In April, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which represents the influence of relative humidity on air temperature, is computed to be 30°C (86°F).

What is the average humidity in December in Georgetown?

In Georgetown, Saint Helena, Ascension and Tristan da Cunha, the average relative humidity in December is 80%.

How many days does it rain in December in Georgetown?

In Georgetown, during December, the rain falls for 12.1 days and regularly aggregates up to 11mm (0.43") of precipitation.

When are the longest days in Georgetown?

December has the longest days of the year in Georgetown, with an average of 12h and 36min of daylight.

What is the average length of the day in December in Georgetown?

In December, the average day length in Georgetown, Saint Helena, Ascension and Tristan da Cunha, is 12h and 35min.

When are sunrise and sunset in December in Georgetown?

In December, on the first day of the month, sunrise is at 06:30 and sunset at 19:03. On the last day of the month, in Georgetown, Saint Helena, Ascension and Tristan da Cunha, sunrise is at 06:43 and sunset at 19:18 GMT.

How long on average sun shines in December in Georgetown?

In Georgetown, Saint Helena, Ascension and Tristan da Cunha, the average sunshine duration in December is 5.9h.

How high is the UV index in December in Georgetown?

In December, the average daily maximum UV index is 6. A UV Index value of 6 to 7 symbolizes a high health threat from exposure to Sun's UV rays.
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Average temperature in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average temperature in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average high temperature in December: 24.4°C

The warmest month (with the highest average high temperature) is April (27.3°C).
The month with the lowest average high temperature is September (23.5°C).

  • Average low temperature in December: 23.7°C

The month with the highest average low temperature is April (26.2°C).
The coldest months (with the lowest average low temperature) are September and November (23°C).

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Average pressure in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average pressure in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average pressure in December: 1013mbar

The months with the highest atmospheric pressure are July and August (1016.1mbar).
The months with the lowest atmospheric pressure are February and March (1011.8mbar).

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Average wind speed in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average wind speed in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average wind speed in December: 23.9km/h

The windiest month (with the highest average wind speed) is July (28.1km/h).
The calmest month (with the lowest average wind speed) is January (21.7km/h).

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Average humidity in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average humidity in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average humidity in December: 80%

The months with the highest relative humidity are October and November (81%).
The months with the lowest relative humidity are June and July (75%).

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Average rainfall in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average rainfall in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average rainfall in December: 11mm

The wettest month (with the highest rainfall) is July (20mm).
The driest months (with the least rainfall) are January and February (8mm).

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Average rainfall days in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average rainfall days in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average rainfall days in December: 12.1 days

The month with the highest number of rainy days is August (19.8 days).
The month with the least rainy days is February (7.4 days).

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Average daylight in December /
Average sunshine in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average daylight in December / Average sunshine in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average daylight in December: 12h and 4min

The month with the longest days is December (Average daylight: 12h and 36min).
The month with the shortest days is June (Average daylight: 11h and 42min).

  • Average sunshine in December: 5h and 5min

The month with the most sunshine is March (Average sunshine: 8h and 6min).
The month with the least sunshine is October (Average sunshine: 5h and 12min).

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Average sunshine days in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average sunshine days in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average sunshine days in December: 4.8 days

The month with the most sunshine days is March (11.3 days).
The month with the least sunshine days is August (1.8 days).

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Average UV index in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average UV index in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average UV index in December: 6

The months with the highest UV index are January, February, March, April and May (UV index 7).
The months with the lowest UV index are September, October and November (UV index 5).

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Average cloud cover in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average cloud cover in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average cloud cover in December: 61

The month with the most cloud cover is October (Cloud cover 68).
The month with the least cloud cover is March (Cloud cover 40).

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Average visibility in December
Georgetown, Saint Helena, Ascension and Tristan da Cunha

Average visibility in December - Georgetown, Saint Helena, Ascension and Tristan da Cunha
  • Average visibility in December: 10km

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).

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Georgetown, Saint Helena, Ascension and Tristan da Cunha

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