Grimsby weather in May

In May, Grimsby sees average daytime highs of 15°C and overnight lows near 9°C, with 80 mm of rain across 10.8 wet days and about 14.4 hours of daylight. It is the 5th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 12°C in the first days to 18°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 54 min at the start of May to 14 h 54 min by month's end. Set against the rest of the year, May is Grimsby's 5th-clearest and 9th-windiest month. For the whole year in context, see Grimsby's year-round climate.

Daytime high
15°
5th warmest
Overnight low
7th coldest
Rainfall
80 mm
10.8 wet days
Daylight
14 h 30 min
5:00 AM – 7:29 PM
Cloud cover
61%
5th clearest
Wind
13 km/h
9th windiest
Solar energy
5.9 kWh/m²
Travel score
4.4
out of 10

Grimsby is town in Niagara Region, Ontario, Canada.

Density
398/km²
people per km²
Founded
1790

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

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 12°C in the first days to 18°C by the end.

A typical May day in Grimsby reaches about 15°C in the afternoon and slips back to 9°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 10°C and 20°C. Set against its neighbours, May runs about 6°C warmer than April and about 6°C cooler than June.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
1126
2126
3127
4127
5137
6137
7137
8138
9138
10148
11148
12148
13148
14149
15159
16159
17159
18159
191610
201610
211610
221610
231611
241711
251711
261711
271712
281812
291812
301812
311813

How May really feels in Grimsby

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.

Grimsby weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-0° / -5°7311.58.59.20.0
Feb-0° / -6°588.66.610.20.0
Mar / -2°719.94.511.60.1
Apr / 9511.41.813.11.7
May15° / 8010.8014.44.4
Jun21° / 16°8210.8015.16.4
Jul25° / 19°749.7014.97.0
Aug24° / 19°679.7013.87.1
Sep21° / 16°789.3012.36.6
Oct14° / 8811.3010.84.1
Nov / 8110.61.99.51.4
Dec / -1°7511.15.88.90.0

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 16% of May, with mostly cloudy or overcast conditions the remaining 56%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14159
24159
34258
44357
54357
64258
74258
84258
94258
104357
114357
124357
134357
144357
154357
164357
174555
184456
194456
204456
214654
224654
234753
244753
254753
264753
274753
284753
294852
304753
314753

Chance of precipitation in May

Any precipitation

Grimsby gets around 80 mm of rain over 10.8 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 35% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
137
237
337
437
537
637
737
837
937
1037
1137
1237
1336
1436
1536
1636
1735
1835
1934
2034
2133
2233
2333
2433
2533
2633
2733
2833
2933
3033
3133

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 89% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
199100
299100
398200
498200
598200
698200
797300
897300
997300
1096400
1196400
1295500
1395500
1494600
1593700
1692710
1791810
1890910
19881020
20871120
21851230
22841330
23821440
24791551
25781651
26771661
27751771
28741871
29731881
30711991
31702091

Wind in May

Winds average 13 km/h in May.

Across May, daily wind ranges from about 12 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
114light breeze
214light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2612light breeze
2712light breeze
2812light breeze
2912light breeze
3012light breeze
3112light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 54 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 60 minutes over May. Sunrise moves from 5:19 AM to 4:48 AM, and sunset from 7:12 PM to 7:43 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.95:197:12
213.95:187:13
314.05:167:14
414.05:157:15
514.05:147:16
614.15:127:18
714.15:117:19
814.25:107:20
914.25:087:21
1014.25:077:22
1114.35:067:23
1214.35:057:24
1314.45:047:25
1414.45:027:27
1514.45:017:28
1614.55:007:29
1714.54:597:30
1814.54:587:31
1914.64:577:32
2014.64:567:33
2114.64:557:34
2214.74:547:35
2314.74:547:36
2414.74:537:37
2514.84:527:38
2614.84:517:39
2714.84:507:40
2814.94:507:41
2914.94:497:42
3014.94:487:43
3114.94:487:43

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.9 kWh/m².

For context, solar energy here swings from a low near 1.29 kWh/m² to a high of 6.29 kWh/m² in June across the year — May's 5.9 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.5Bright
45.6Bright
55.6Bright
65.6Bright
75.7Bright
85.7Bright
95.7Bright
105.7Bright
115.8Bright
125.8Bright
135.8Bright
145.8Bright
155.8Bright
165.9Bright
175.9Bright
185.9Bright
196.0Bright
206.0Bright
216.0Intense
226.0Intense
236.1Intense
246.1Intense
256.1Intense
266.1Intense
276.1Intense
286.1Intense
296.2Intense
306.2Intense
316.2Intense
Planning a trip in May

Is May a good time to visit Grimsby?

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

4.4
Sightseeing
5th-best month of the year
0.6
Beach & pool
5th-best month of the year

May is a reasonable time to visit Grimsby for sightseeing.

What to pack for Grimsby in May

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

In May, Grimsby sees daytime highs around 15°C and nights near 9°C. Worth packing: a warm layer, rain gear and sun protection. About 11 days see rain.

a warm layerrain gearsun protection

Sea temperature near Grimsby in May

The nearest coast averages about 8°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 20 km away) is warmest in August at about 21°C and coldest in February near 3°C.

It's comfortable for a long swim from Jul 22 to Sep 1 — about 1.4 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°C)Comfort
Jan4Bracing
Feb3Bracing
Mar3Bracing
Apr4Bracing
May8Bracing
Jun15Cool
Jul20Cool
Aug21Refreshing
Sep19Cool
Oct13Bracing
Nov8Bracing
Dec5Bracing

UV index in Grimsby in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Grimsby peaks around June 20 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 20UV 8Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May6High
Jun8Very high
Jul8Very high
Aug6High
Sep5High
Oct3Moderate
Nov2Low
Dec1Low

Air quality in Grimsby in May

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Grimsby is worst in May — around 22 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (December, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodMay 2021 µg/m³Dec 1010 µg/m³
PM2.5 (µg/m³)Level
Jan12Good
Feb15Moderate
Mar18Moderate
Apr18Moderate
May22Moderate
Jun20Moderate
Jul20Moderate
Aug17Moderate
Sep17Moderate
Oct11Good
Nov10Good
Dec10Good
Location & terrain

Where is Grimsby?

Grimsby sits at 43.2°N, 79.6°W, 88 m above sea level, in Canada. The nearest listed city is Stoney Creek, 16 km away.

Topography around Grimsby

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

Within 3 km, the terrain around Grimsby has only modest variations in elevation — a maximum elevation change of 145 m around an average of 110 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 155 m; within 80 km, significant variations in elevation — a maximum elevation change of 401 m.

The land around Grimsby is covered by water (41%) and trees (23%) within 3 km, water (45%) and cropland (23%) within 16 km, and water (38%), trees (21%) and cropland (21%) within 80 km.

3 km
145 m
16 km
155 m
80 km
401 m
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Stoney Creek 16 km · Hamilton 24 km · St. Catharines 26 km · Oakville 29 km · Waterdown 30 km · Burlington 30 km · Thorold 31 km · Ancaster 34 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 Grimsby (43.2001°, -79.5663°, elevation 88 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. 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).