Castries climate
Castries (Saint Lucia) has a tropical monsoon climate (Köppen Am). The average temperature over the year is 27 °C80 °F, and about 1,444 mm57 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Castries climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 2679 | 2577 | 2678 | 682.7 |
| Feb | 2679 | 2577 | 2678 | 441.7 |
| Mar | 2780 | 2577 | 2678 | 481.9 |
| Apr | 2781 | 2678 | 2679 | 973.8 |
| May | 2882 | 2679 | 2780 | 1024.0 |
| Jun | 2882 | 2780 | 2781 | 1365.4 |
| Jul | 2882 | 2780 | 2781 | 1546.1 |
| Aug | 2883 | 2781 | 2882 | 1807.1 |
| Sep | 2983 | 2781 | 2882 | 1817.1 |
| Oct | 2883 | 2781 | 2882 | 1897.4 |
| Nov | 2882 | 2780 | 2781 | 1596.3 |
| Dec | 2781 | 2679 | 2680 | 853.4 |
| Year | 2983 | 2577 | 2780 | 1,44457 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 76% | 41% | 5.2 | 11:23 |
| Feb | 74% | 40% | 5.8 | 11:40 |
| Mar | 75% | 44% | 6.3 | 12:01 |
| Apr | 76% | 53% | 6.5 | 12:26 |
| May | 77% | 55% | 6.3 | 12:46 |
| Jun | 78% | 62% | 5.9 | 12:57 |
| Jul | 79% | 54% | 6.0 | 12:53 |
| Aug | 79% | 48% | 6.2 | 12:35 |
| Sep | 78% | 52% | 6.0 | 12:11 |
| Oct | 79% | 56% | 5.4 | 11:48 |
| Nov | 79% | 49% | 5.0 | 11:28 |
| Dec | 77% | 42% | 5.0 | 11:18 |
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 Castries is like
The warmest month is September, with an average high of 29 °C83 °F and a low of 27 °C81 °F. The coldest is February, when highs average 26 °C79 °F and lows 25 °C77 °F. Temperatures barely change through the year: the warmest and the coolest month differ by only 2.4 °C4.3 °F.
It is wet, with about 1,444 mm57 in of precipitation per year. The wettest three-month stretch is August–October, which brings 38% of the annual total. The wettest month is October (189 mm7.4 in), the driest is February (44 mm1.7 in).
Relative humidity ranges from 74% in February to 79% in July. The clearest skies (lowest average cloud amount, 40%) are typical of February. Average wind speed near the ground ranges from 17 km/h (11 mph) in September to 24 km/h (15 mph) in February. Daylight lasts from about 11.3 hours in December to 12.9 hours in June.
Best time to visit Castries
Based on these averages, the most comfortable months for sightseeing and outdoor activities are December–March: average highs of 26 °C79 °F to 27 °C81 °F with 44 mm1.7 in to 85 mm3.4 in of precipitation per month.
The most challenging month is October, which is very wet (189 mm7.4 in) and humid (79% relative humidity).
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 Castries
- Wetter months (June–November) — highs 2882 to 29 °C83 °F, lows around 27 °C80 °F, about 167 mm6.6 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses and an umbrella or light rain jacket.
- Drier months (December–May) — highs 2679 to 28 °C82 °F, lows 2577 to 26 °C79 °F, about 74 mm2.9 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses.
How Castries compares
Compared with Fort-de-France, about 68 km to the north, Castries is on average 0.7 °C1.2 °F cooler and receives a similar amount of precipitation. The difference is largest in July (0.8 °C1.4 °F cooler).
Places in other countries with the most similar temperature and rainfall pattern: Roseau (Dominica, Am), Fort-de-France (Martinique, Am) and Carolina (Puerto Rico, Aw).
Nearby places
- Fort-de-France 68 km · 27 °C81 °F · 1,478 mm58 in
- Kingstown 96 km · 28 °C82 °F · 682 mm27 in
- Roseau 151 km · 27 °C81 °F · 1,419 mm56 in
- Bridgetown 179 km · 27 °C81 °F · 777 mm31 in
- Saint Georges 231 km · 28 °C82 °F · 1,301 mm51 in
- Basse-Terre 236 km · 27 °C81 °F · 1,171 mm46 in
- Plymouth 328 km · 27 °C80 °F · 1,003 mm39 in
- Saint Johns 359 km · 27 °C81 °F · 1,108 mm44 in
Frequently asked questions
What is the warmest month in Castries?
September is the warmest month in Castries, with an average high of 29 °C (83 °F) and an average low of 27 °C (81 °F).
What is the coldest month in Castries?
February is the coldest month, with an average high of 26 °C (79 °F) and an average low of 25 °C (77 °F).
When does it rain the most in Castries?
October is the wettest month with about 189 mm (7.4 in) of precipitation; February is the driest with about 44 mm (1.7 in).
What is the best time to visit Castries?
Judging by long-term averages, the most comfortable months are December–March.
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.
The grid cell’s average elevation is 11 m, while Castries lies at about 119 m. Temperatures on this page were therefore adjusted by −0.7 °C1.3 °F using the standard lapse rate of 6.5 °C per 1,000 m.