Suomenlinna weather in May

In May, Suomenlinna sees average daytime highs of 14°C and overnight lows near 6°C, with 46 mm of precipitation across 9.3 wet days and about 16.8 hours of daylight. It is the 5th-warmest and 9th-wettest month of the year here.

Highs climb over the month, from about 12°C in the first days to 16°C by the end. The sky is clear or mostly clear about 29% of the time in May, and the air most often feels dry.

Daylight stretches from about 15 h 36 min at the start of May to 17 h 54 min by month's end. Set against the rest of the year, May is Suomenlinna's 1st-clearest and 10th-windiest month. For the whole year in context, see Suomenlinna's year-round climate.

Daytime high
14°
5th warmest
Overnight low
8th coldest
Precipitation
46 mm
9.3 wet days
Daylight
16 h 48 min
3:52 AM – 8:41 PM
Cloud cover
59%
1st clearest
Wind
13 km/h
10th windiest
Solar energy
5.54 kWh/m²
Travel score
4.3
out of 10

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 16°C by the end.

A typical May day in Suomenlinna reaches about 14°C in the afternoon and slips back to 6°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 9°C and 20°C. Set against its neighbours, May runs about 6°C warmer than April and about 4°C cooler than June.

10°20°151015202531
Avg high (°C)Avg low (°C)
1123
2123
3123
4123
5124
6134
7134
8134
9134
10134
11135
12145
13145
14145
15145
16146
17146
18146
19156
20156
21156
22157
23157
24157
25167
26167
27168
28168
29168
30178
31178

How May really feels in Suomenlinna

Once humidity and wind are folded in, May averages 0 days that feel above 32°C and 2 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
2
wind chill below the day's low

The story in May is cold — wind chill drags the overnight "feels like" below the raw low.

Suomenlinna weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-2° / -7°4710.910.16.40.0
Feb-3° / -8°429.58.68.60.0
Mar / -5°368.4711.30.0
Apr / 378.52.314.21.4
May14° / 469.30.116.84.3
Jun19° / 11°7411.8018.45.6
Jul22° / 14°7812.1017.76.3
Aug20° / 13°7412015.46.0
Sep15° / 5810.5012.64.4
Oct / 6011.40.79.71.5
Nov / 5811.64.47.10.0
Dec / -4°5612.18.85.60.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in May, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 18% of May, with mostly cloudy or overcast conditions the remaining 53%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14654
24654
34555
44654
54654
64654
74654
84654
94654
104654
114654
124753
134753
144753
154753
164753
174753
184753
194753
204654
214654
224753
234753
244753
254753
264753
274753
284753
294753
304852
314852

Chance of precipitation in May

Any precipitationSnow

Suomenlinna gets around 46 mm of rain and snow over 9.3 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 29% and peaks near 32% on the wettest days, and about 0 day brings snow.

0%10%20%30%40%151015202531
Rain chance (%)Snow chance (%)
1283
2282
3282
4282
5282
6282
7281
8281
9281
10281
11281
12271
13270
14270
15280
16280
17280
18290
19300
20300
21310
22310
23310
24320
25320
26320
27320
28320
29320
30320
31320

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 98% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
11000
21000
31000
41000
51000
61000
71000
81000
91000
10991
11991
12991
13991
14991
15982
16982
17982
18982
19982
20982
21982
22973
23973
24973
25973
26973
27964
28964
29964
30964
31964

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 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
112light breeze
212light breeze
312light breeze
412light breeze
512light breeze
612light breeze
712light breeze
812light breeze
912light breeze
1012light breeze
1112light breeze
1212light 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
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze
3113light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 15 h 36 min at the start of May to 17 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 138 minutes over May. Sunrise moves from 4:30 AM to 3:22 AM, and sunset from 8:04 PM to 9:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
115.64:308:04
215.74:278:07
315.74:258:09
415.84:228:12
515.94:198:14
616.04:178:17
716.14:148:19
816.24:118:22
916.34:098:24
1016.34:068:27
1116.44:048:29
1216.54:018:32
1316.63:598:34
1416.73:568:36
1516.73:548:39
1616.83:528:41
1716.93:498:43
1817.03:478:46
1917.13:458:48
2017.13:438:50
2117.23:408:53
2217.33:388:55
2317.33:368:57
2417.43:348:59
2517.53:329:01
2617.53:309:03
2717.63:299:05
2817.73:279:07
2917.73:259:09
3017.83:239:11
3117.93:229:13

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.54 kWh/m².

For context, solar energy here swings from a low near 0.16 kWh/m² to a high of 5.82 kWh/m² in June across the year — May's 5.54 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.0Bright
25.0Bright
35.1Bright
45.1Bright
55.2Bright
65.2Bright
75.3Bright
85.3Bright
95.3Bright
105.4Bright
115.4Bright
125.5Bright
135.5Bright
145.5Bright
155.5Bright
165.6Bright
175.6Bright
185.6Bright
195.6Bright
205.7Bright
215.7Bright
225.7Bright
235.7Bright
245.7Bright
255.8Bright
265.8Bright
275.8Bright
285.8Bright
295.8Bright
305.8Bright
315.9Bright
Planning a trip in May

Is May a good time to visit Suomenlinna?

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

4.3
Sightseeing
5th-best month of the year
0.2
Beach & pool
5th-best month of the year

May is a reasonable time to visit Suomenlinna for sightseeing.

What to pack for Suomenlinna in May

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

In May, Suomenlinna sees daytime highs around 14°C and nights near 6°C. Worth packing: a warm layer, rain gear and sun protection. About 9 days see rain.

a warm layerrain gearsun protection

Sea temperature near Suomenlinna in May

The nearest coast averages about 6°C in May — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 17°C and coldest in March near 1°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan2Bracing
Feb1Bracing
Mar1Bracing
Apr2Bracing
May6Bracing
Jun11Bracing
Jul16Cool
Aug17Cool
Sep14Bracing
Oct10Bracing
Nov7Bracing
Dec4Bracing

UV index in Suomenlinna in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Suomenlinna peaks around June 18 at about 5 (high) — a little sun protection helps at midday. It bottoms out near January 1 at about 0 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 4 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJun 18UV 5Jan 1UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar2Low
Apr3Moderate
May4Moderate
Jun5High
Jul5Moderate
Aug5Moderate
Sep3Moderate
Oct1Low
Nov0Low
Dec0Low
Location & terrain

Where is Suomenlinna?

Suomenlinna sits at 60.1°N, 25.0°E, 0 m above sea level, in Finland. The nearest listed city is Helsinki, 4.0 km away.

Topography around Suomenlinna

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

Within 3 km, the terrain around Suomenlinna has only modest variations in elevation — a maximum elevation change of 35 m around an average of 3 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 83 m; within 80 km, only modest variations in elevation — a maximum elevation change of 193 m.

The land around Suomenlinna is covered by water (77%) within 3 km, water (62%) and trees (21%) within 16 km, and water (50%) and trees (38%) within 80 km.

3 km
35 m
16 km
83 m
80 km
193 m
treesgrasslandcroplandartificial surfaceswater
May weather nearby: Helsinki 4.0 km · Laajasalo 4.0 km · Kallio 5.0 km · Taka-Töölö 5.0 km · Herttoniemi 6.0 km · Lauttasaari 7.0 km · Munkkiniemi 8.0 km · Viikki 8.0 km

Finland travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 85% of US
price level, 2025
GDP per capita
$56,149
2025
Happiness
7.8 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1
per 100k, 2023
Road deaths
3.9
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 603
Religion
Lutheran 67%none 31%other 2%Greek Orthodox 1%

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 Suomenlinna (60.1478°, 24.9856°, elevation 0 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).