Jamestown climate
Jamestown (Saint Helena) has a hot desert climate (Köppen BWh). The average temperature over the year is 22 °C71 °F, and about 58 mm2.3 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Jamestown climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 2374 | 2373 | 2373 | 30.1 |
| Feb | 2476 | 2475 | 2475 | 40.2 |
| Mar | 2577 | 2476 | 2576 | 60.2 |
| Apr | 2476 | 2475 | 2475 | 50.2 |
| May | 2374 | 2373 | 2373 | 70.3 |
| Jun | 2272 | 2271 | 2271 | 80.3 |
| Jul | 2170 | 2069 | 2169 | 50.2 |
| Aug | 2068 | 2067 | 2068 | 50.2 |
| Sep | 2068 | 1967 | 2067 | 40.2 |
| Oct | 2068 | 1967 | 2067 | 40.2 |
| Nov | 2169 | 2068 | 2068 | 30.1 |
| Dec | 2271 | 2170 | 2171 | 30.1 |
| Year | 2577 | 1967 | 2271 | 582.3 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 78% | 61% | 6.9 | 12:58 |
| Feb | 77% | 53% | 6.9 | 12:38 |
| Mar | 77% | 55% | 6.4 | 12:13 |
| Apr | 76% | 59% | 5.5 | 11:45 |
| May | 75% | 57% | 4.8 | 11:23 |
| Jun | 73% | 67% | 4.2 | 11:11 |
| Jul | 74% | 69% | 4.2 | 11:16 |
| Aug | 76% | 82% | 4.4 | 11:35 |
| Sep | 78% | 85% | 4.6 | 12:02 |
| Oct | 80% | 87% | 5.0 | 12:29 |
| Nov | 79% | 80% | 5.6 | 12:53 |
| Dec | 78% | 71% | 6.4 | 13:04 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Jamestown is like
The warmest month is March, with an average high of 25 °C77 °F and a low of 24 °C76 °F. The coldest is September, when highs average 20 °C68 °F and lows 19 °C67 °F. Seasonal differences are small — just 4.9 °C8.8 °F between the warmest and the coolest month.
It is very dry, with only 58 mm2.3 in of precipitation in an average year. The wettest three-month stretch is May–July, which brings 35% of the annual total. The wettest month is June (8 mm0.3 in), the driest is January (3 mm0.1 in).
Relative humidity ranges from 73% in June to 80% in October. The clearest skies (lowest average cloud amount, 53%) are typical of February. Average wind speed near the ground ranges from 19 km/h (12 mph) in January to 23 km/h (14 mph) in August. Daylight lasts from about 11.2 hours in June to 13.1 hours in December.
Best time to visit Jamestown
Based on these averages, the most comfortable months for sightseeing and outdoor activities are all year: average highs of 20 °C68 °F to 25 °C77 °F with 3 mm0.1 in to 8 mm0.3 in of precipitation per month.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Jamestown
- Wetter months (March, May–August) — highs 2068 to 25 °C77 °F, lows 2067 to 24 °C76 °F, about 6 mm0.2 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket.
- Drier months (September–February, April) — highs 2068 to 24 °C76 °F, lows 1967 to 24 °C75 °F, about 4 mm0.1 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket.
How Jamestown compares
Places in other countries with the most similar temperature and rainfall pattern (seasons shifted for the other hemisphere where needed): Chincha Alta (Peru, BWh), Chimbote (Peru, BWh) and Nouadhibou (Mauritania, BWh).
Nearby places
Frequently asked questions
What is the warmest month in Jamestown?
March is the warmest month in Jamestown, with an average high of 25 °C (77 °F) and an average low of 24 °C (76 °F).
What is the coldest month in Jamestown?
September is the coldest month, with an average high of 20 °C (68 °F) and an average low of 19 °C (67 °F).
When does it rain the most in Jamestown?
June is the wettest month with about 8 mm (0.3 in) of precipitation; January is the driest with about 3 mm (0.1 in).
What is the best time to visit Jamestown?
Judging by long-term averages, the most comfortable months are all year.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.