Castries weather in August

In August, Castries sees average daytime highs of 30°C and overnight lows near 26°C, with 99 mm of rain across 20.7 wet days and about 12.5 hours of daylight. It is the 2nd-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 38% of the time in August, and the air most often feels oppressive.

Daylight stretches from about 12 h 36 min at the start of August to 12 h 18 min by month's end. Set against the rest of the year, August is Castries's 7th-clearest and 9th-windiest month. For the whole year in context, see Castries's year-round climate.

Daytime high
30°
2nd warmest
Overnight low
26°
11th coldest
Rainfall
99 mm
20.7 wet days
Daylight
12 h 30 min
5:54 AM – 6:22 PM
Cloud cover
55%
7th clearest
Wind
18 km/h
9th windiest
Solar energy
6.18 kWh/m²
Travel score
4.0
out of 10

Castries is capital of Saint Lucia.

Density
253/km²
people per km²
Founded
1650

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical August day in Castries reaches about 30°C in the afternoon and slips back to 26°C overnight — a 4°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 31°C. Set against its neighbours, August runs on par with July and on par with September.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
13025
23025
33025
43025
53025
63025
73025
83025
93025
103025
113025
123025
133025
143025
153025
163026
173026
183026
193026
203026
213026
223026
233026
243026
253026
263026
273026
283026
293026
303026
313026

How August really feels in Castries

Once humidity and wind are folded in, August averages 31 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in August is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Castries weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan28° / 24°3111.811.36.5
Feb28° / 24°218.811.56.7
Mar28° / 24°269.811.96.1
Apr29° / 25°3611.512.35.4
May29° / 25°4712.512.64.9
Jun29° / 25°6515.112.84.5
Jul29° / 25°8320.312.74.2
Aug30° / 26°9920.712.54.0
Sep30° / 26°10419.412.13.9
Oct29° / 25°11920.911.74.0
Nov29° / 25°10218.911.44.5
Dec28° / 25°421311.25.7

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 20% of August, with mostly cloudy or overcast conditions the remaining 42%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16238
26139
36139
46139
56139
66040
76040
86040
96040
106040
116040
126040
136040
146040
155941
165941
175941
185941
195842
205842
215743
225644
235644
245545
255545
265446
275446
285347
295347
305248
315248

Chance of precipitation in August

Any precipitation

Castries gets around 99 mm of rain over 20.7 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 68% and peaks near 70% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
170
270
370
470
570
670
770
870
970
1070
1170
1270
1370
1470
1570
1669
1769
1869
1968
2068
2167
2266
2366
2465
2565
2664
2764
2864
2963
3063
3162

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

Most of August feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, August lands in the oppressive band about 87% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
19010
29010
39010
48911
58911
68911
78911
88911
98812
108812
118812
128812
138812
148812
158812
168713
178713
188713
198713
208713
218713
228614
238614
248614
258614
268614
278614
288614
298614
308614
318515

Wind in August

Winds average 18 km/h in August.

Across August, daily wind ranges from about 17 km/h on the calmest days to 20 km/h at its breeziest. It stays fairly steady from day to day.

0510152025151015202531
Wind speed (km/h)Feels
120light breeze
220light breeze
319light breeze
419light breeze
519light breeze
619light breeze
719light breeze
819light breeze
919light breeze
1019light breeze
1119light breeze
1219light breeze
1319light breeze
1418light breeze
1518light breeze
1618light breeze
1718light breeze
1818light breeze
1918light breeze
2018light breeze
2118light breeze
2218light breeze
2318light breeze
2417light breeze
2517light breeze
2617light breeze
2717light breeze
2817light breeze
2917light breeze
3017light breeze
3117light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 12 h 36 min at the start of August to 12 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 18 minutes over August. Sunrise moves from 5:51 AM to 5:55 AM, and sunset from 6:29 PM to 6:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.65:516:29
212.65:516:29
312.65:526:28
412.65:526:28
512.65:526:27
612.65:526:27
712.65:536:27
812.65:536:26
912.55:536:26
1012.55:536:25
1112.55:536:25
1212.55:536:24
1312.55:546:24
1412.55:546:23
1512.55:546:23
1612.55:546:22
1712.55:546:22
1812.45:546:21
1912.45:546:21
2012.45:556:20
2112.45:556:19
2212.45:556:19
2312.45:556:18
2412.45:556:17
2512.45:556:17
2612.45:556:16
2712.35:556:15
2812.35:556:15
2912.35:556:14
3012.35:556:13
3112.35:556:13

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 6.18 kWh/m².

For context, solar energy here swings from a low near 4.95 kWh/m² to a high of 6.65 kWh/m² in April across the year — August's 6.18 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.2Intense
26.2Intense
36.2Intense
46.2Intense
56.2Intense
66.2Intense
76.2Intense
86.2Intense
96.2Intense
106.2Intense
116.2Intense
126.2Intense
136.2Intense
146.2Intense
156.2Intense
166.2Intense
176.2Intense
186.2Intense
196.2Intense
206.2Intense
216.2Intense
226.2Intense
236.2Intense
246.2Intense
256.2Intense
266.2Intense
276.2Intense
286.2Intense
296.2Intense
306.2Intense
316.2Intense
Planning a trip in August

Hazard calendar for Castries

In seasonPeak

In August, Castries sits inside its atlantic hurricane and rainy season season. The full year is below, with each hazard's peak months called out.

Castries sits in the Atlantic hurricane belt; the season peaks August–October.

Castries's rainy season runs June–November, when most of the year's rain falls.

Castries sees seasonal dust haze (June–July), heaviest in June.

Atlantic hurricane
Rainy season
Dust
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is August a good time to visit Castries?

Our two travel scores rate August for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

4.0
Sightseeing
10th-best month of the year
5.3
Beach & pool
11th-best month of the year

August is a reasonable time to visit Castries for sightseeing.

What to pack for Castries in August

From August's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In August, Castries sees daytime highs around 30°C and nights near 26°C. Pack light clothes, rain gear and sun protection. About 21 days see rain.

light clothesrain gearsun protection

Sea temperature near Castries in August

The nearest coast averages about 29°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 19 km away) is warmest in September at about 29°C and coldest in February near 27°C.

The water stays above 20°C all year — warm enough for a swim any month.

26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan27Warm
Feb27Warm
Mar27Warm
Apr27Warm
May28Warm
Jun28Warm
Jul28Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov29Tropical
Dec28Warm

UV index in Castries in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 11 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Castries peaks around March 21 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 13 at about 8 (very high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highMar 21UV 14Dec 13UV 8
UV index (midday)Level
Jan9Very high
Feb12Extreme
Mar14Extreme
Apr13Extreme
May12Extreme
Jun11Extreme
Jul12Extreme
Aug11Extreme
Sep12Extreme
Oct11Extreme
Nov9Very high
Dec8Very high

Air quality in Castries in August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.

Air quality in Castries is worst in June — around 29 µg/m³ PM2.5 (moderate), about 2.9× the cleanest month (December, 10 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

010203040JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJun 1929 µg/m³Dec 2310 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb14Moderate
Mar12Good
Apr16Moderate
May19Moderate
Jun29Moderate
Jul25Moderate
Aug21Moderate
Sep15Moderate
Oct18Moderate
Nov13Moderate
Dec10Good
Location & terrain

Where is Castries?

Castries sits at 14.0°N, 61.0°W, 119 m above sea level, in Saint Lucia. The nearest listed city is Gros Islet, 10 km away.

Gros IsletSoufriereVieux Fort

Topography around Castries

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Castries.

Within 3 km, the terrain around Castries has significant variations in elevation — a maximum elevation change of 266 m around an average of 45 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 900 m; within 80 km, large variations in elevation — a maximum elevation change of 1,191 m.

The land around Castries is covered by trees (46%) and water (35%) within 3 km, water (55%) and trees (42%) within 16 km, and water (89%) within 80 km.

3 km
266 m
16 km
900 m
80 km
1,191 m
treesgrasslandartificial surfaceswaterwetland
August weather nearby: Gros Islet 10 km · Soufriere 16 km · Vieux Fort 32 km · Ducos 65 km · Fort-de-France 68 km · Le Lamentin 69 km · Le François 70 km · Saint-Joseph 75 km

Saint Lucia travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B / G
240 V · 50 Hz
Prices
≈ 51% of US
price level, 2025
GDP per capita
$14,746
2025
Homicide rate
39
per 100k, 2023
Road deaths
29.8
per 100k/yr, 2019
Income group
Upper middle
World Bank
Religion
Roman Catholic 62%Protestant 26%none 6%other Christian 3%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Castries (13.9957°, -61.0061°, elevation 119 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).