St. Thomas weather in May

In May, St. Thomas sees average daytime highs of 17°C and overnight lows near 10°C, with 94 mm of rain across 12.1 wet days and about 14.4 hours of daylight. It is the 5th-warmest and 4th-wettest month of the year here.

Highs climb over the month, from about 14°C in the first days to 20°C by the end. The sky is clear or mostly clear about 28% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 48 min at the start of May to 14 h 54 min by month's end. Set against the rest of the year, May is St. Thomas's 5th-clearest and 8th-windiest month. For the whole year in context, see St. Thomas's year-round climate.

Daytime high
17°
5th warmest
Overnight low
10°
8th coldest
Rainfall
94 mm
12.1 wet days
Daylight
14 h 24 min
5:08 AM – 7:34 PM
Cloud cover
61%
5th clearest
Wind
16 km/h
8th windiest
Solar energy
6.1 kWh/m²
Travel score
5.1
out of 10

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 14°C in the first days to 20°C by the end.

A typical May day in St. Thomas reaches about 17°C in the afternoon and slips back to 10°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 12°C and 23°C. Set against its neighbours, May runs about 7°C warmer than April and about 6°C cooler than June.

10°20°30°151015202531
Avg high (°C)Avg low (°C)
1137
2147
3147
4147
5148
6158
7158
8158
9159
10169
11169
12169
13169
141610
151710
161710
171710
181710
191811
201811
211811
221811
231912
241912
251912
261912
272012
282013
292013
302013
312013

How May really feels in St. Thomas

Once humidity and wind are folded in, May averages 0 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
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

St. Thomas weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-1° / -7°7511.58.39.20.0
Feb-1° / -7°589.4710.30.0
Mar / -3°7310.34.911.60.1
Apr10° / 9511.71.713.12.1
May17° / 10°9412.1014.45.1
Jun23° / 16°9911.7015.16.6
Jul25° / 19°9612014.86.6
Aug25° / 18°8210.2013.77.0
Sep21° / 14°849.4012.36.6
Oct14° / 8611.50.110.84.0
Nov / 8110.82.69.61.0
Dec / -3°7411.57.18.90.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 28% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 15% of May, with mostly cloudy or overcast conditions the remaining 56%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14159
24159
34159
44159
54159
64159
74060
84060
94159
104159
114159
124159
134258
144357
154357
164357
174357
184357
194357
204456
214555
224654
234753
244753
254753
264753
274753
284753
294753
304753
314852

Chance of precipitation in May

Any precipitation

St. Thomas gets around 94 mm of rain over 12.1 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 39% and peaks near 41% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
140
240
340
440
540
641
741
841
941
1041
1141
1241
1341
1441
1540
1640
1740
1839
1939
2038
2138
2238
2337
2437
2537
2637
2737
2837
2937
3037
3137

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the dry band about 81% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1972100
2963100
3963100
4953200
5944200
6944200
7925300
8925300
9916300
10906400
11897400
12887500
13878500
14868600
15859600
168310700
178110810
188011810
197911910
2077121010
2176121020
2273131121
2371131231
2470141231
2569141331
2667151341
2766151441
2864161451
2964161451
3061171561
3160181561

Wind in May

Winds average 16 km/h in May.

Across May, daily wind ranges from about 15 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
116light breeze
216light breeze
316light breeze
416light breeze
516light breeze
616light breeze
716light breeze
816light breeze
916light breeze
1016light breeze
1116light breeze
1216light breeze
1316light breeze
1416light breeze
1516light breeze
1616light breeze
1716light breeze
1816light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2316light breeze
2416light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2915light breeze
3015light breeze
3115light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 48 min at the start of May to 14 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 66 minutes over May. Sunrise moves from 5:27 AM to 4:56 AM, and sunset from 7:17 PM to 7:49 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.85:277:17
213.95:257:18
313.95:247:20
414.05:227:21
514.05:217:22
614.15:207:23
714.15:187:24
814.15:177:25
914.25:167:26
1014.25:157:28
1114.35:137:29
1214.35:127:30
1314.35:117:31
1414.45:107:32
1514.45:097:33
1614.45:087:34
1714.55:077:35
1814.55:067:36
1914.55:057:37
2014.65:047:38
2114.65:037:39
2214.65:027:40
2314.75:017:41
2414.75:007:42
2514.75:007:43
2614.84:597:44
2714.84:587:45
2814.84:587:46
2914.84:577:47
3014.94:567:48
3114.94:567:49

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 6.1 kWh/m².

For context, solar energy here swings from a low near 1.34 kWh/m² to a high of 6.64 kWh/m² in June across the year — May's 6.1 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.7Bright
25.7Bright
35.7Bright
45.8Bright
55.8Bright
65.8Bright
75.8Bright
85.9Bright
95.9Bright
105.9Bright
115.9Bright
126.0Bright
136.0Bright
146.0Intense
156.0Intense
166.1Intense
176.1Intense
186.1Intense
196.2Intense
206.2Intense
216.2Intense
226.3Intense
236.3Intense
246.3Intense
256.3Intense
266.3Intense
276.4Intense
286.4Intense
296.4Intense
306.4Intense
316.5Intense
Planning a trip in May

Is May a good time to visit St. Thomas?

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

5.1
Sightseeing
5th-best month of the year
1.4
Beach & pool
5th-best month of the year

May is a reasonable time to visit St. Thomas for sightseeing.

What to pack for St. Thomas in May

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

In May, St. Thomas sees daytime highs around 17°C and nights near 10°C. Pack sun protection. Worth having: a warm layer and rain gear. About 12 days see rain.

sun protectiona warm layerrain gear

Sea temperature near St. Thomas in May

The nearest coast averages about 10°C in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 17 km away) is warmest in August at about 23°C and coldest in February near 1°C.

It's comfortable for a long swim from Jul 5 to Sep 20 — about 2.6 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan2Bracing
Feb1Bracing
Mar1Bracing
Apr4Bracing
May10Bracing
Jun17Cool
Jul22Refreshing
Aug23Refreshing
Sep21Refreshing
Oct16Cool
Nov10Bracing
Dec5Bracing

UV index in St. Thomas in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in St. Thomas peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 23UV 9Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May7High
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is St. Thomas?

St. Thomas sits at 42.8°N, 81.2°W, 232 m above sea level, in Canada. The nearest listed city is London, 24 km away.

Topography around St. Thomas

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

Within 3 km, the terrain around St. Thomas has only modest variations in elevation — a maximum elevation change of 65 m around an average of 233 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 125 m; within 80 km, significant variations in elevation — a maximum elevation change of 251 m.

The land around St. Thomas is covered by trees (35%) and artificial surfaces (33%) within 3 km, cropland (60%) and trees (20%) within 16 km, and cropland (49%) and water (33%) within 80 km.

3 km
65 m
16 km
125 m
80 km
251 m
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: London 24 km · Tillsonburg 38 km · Strathroy 41 km · Woodstock 53 km · Norfolk County 65 km · Stratford 69 km · Brant 79 km · Brantford 84 km

Canada travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 83% of US
price level, 2025
GDP per capita
$55,698
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
97%
of population, 2024
Homicide rate
2
per 100k, 2023
Road deaths
5.3
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 53%none 35%Muslim 5%Hindu 2%

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 St. Thomas (42.7736°, -81.1804°, elevation 232 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. 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).