St Helena weather is warm and mild, tempered by the southeast trade winds. Winter to summer temperatures can range from 11C – 34C (52F – 93F) over the course of the year. Our southern hemisphere seasons are opposite to the north with the winter months of June to September being the wettest and coolest.
It’s All About Change
Typically, British, we love talking about the weather and St Helena Island weather often provides something to chat about. Thankfully, we do not suffer extremes, there are no hurricanes, snow, frost or even thunderstorms to set tongues wagging.
Instead it’s the changeability and microclimates that makes St Helena weather a topic of conversation. Weather in any given moment across this 47 square mile island can vary considerably; drier and 5-6 degrees warmer in low lying Jamestown and coastal areas, to wetter and cooler at the higher altitude of St Paul’s.
Whilst country folk might be needing layers and umbrellas, those in Jamestown could be basking in sunshine.
Time For A Holiday
Fickleness aside, it’s generally t shirt or sweater weather and island activities like dolphin trips can be enjoyed all year round.
The preferred season for most holiday-makers is the summer months of December to March which coincides nicely with whale shark season.
Peak diving season falls between December and June with water temperatures averaging 25C and visibility at 30-35m.
St Helena Seasons
Situated below the equator our seasons are opposite to the north.
Summer in St Helena 22 Dec to 21 Mar
15-34C / 59-93F
Autumn (Fall) in St Helena 22 Mar to 21 Jun
14-30C / 57-86F
Winter in St Helena 22 Jun to 21 Sep
13-24C / 55-75F
Spring in St Helena 22 Sep to 21 Dec
13-26C / 55-79F
St Helena Climate
The warmest time of year is December through to April when temperatures average around 22.3C. St Helena humidity is often over 80% and at its highest from July to September.
The month of August is nicknamed ‘Scruffy August‘ because of the weather. So called ‘scruffy’ for the mud, rain, mists and wind experienced during this mid-winter month.
St Helena Weather Data
There is an official Meteorological Station at Bottom Woods, located 436m above sea level. The charts below were generated from data collected at the Met Station for 2018. You might find them useful in planning a visit to St Helena, there is a detailed table at the bottom of this post.
The Bottom Woods Met Station does not issue weather forecasts.
St Helena Average Temperature
Graph below shows why ‘Scruffy August’ has its name!
It’s The Humidity!
Average daily humidity for the year 2018 at Bottom Woods Met Station.
St Helena Sunshine Hours
St Helena Weather in 2018
St Helena Weather on The App
The Inside St Helena App includes weather under its ‘Useful Information’ section, which includes the rainfall, humidity and temperature statistics for St Helena.
The App’s ‘News Alerts’ section is also a good place to get a sense of current weather conditions. At times the government issues St Helena Island weather forecast warnings, usually for high winds or rough sea conditions. This information is posted in the News section, along with drought warnings which can occur when the winter rains are late.