Suomenlinna weather in April

In April, Suomenlinna sees average daytime highs of 8°C and overnight lows near 0°C, with 37 mm of precipitation across 8.5 wet days and about 14.2 hours of daylight. It is the 7th-warmest and 11th-wettest month of the year here.

Highs climb over the month, from about 5°C in the first days to 11°C by the end. The sky is clear or mostly clear about 25% of the time in April, and the air most often feels dry.

Daylight stretches from about 12 h 48 min at the start of April to 15 h 30 min by month's end. Set against the rest of the year, April is Suomenlinna's 5th-clearest and 8th-windiest month. For the whole year in context, see Suomenlinna's year-round climate.

Daytime high: 8°; 7th warmest
Overnight low: 0°; 6th coldest
Precipitation: 37 mm; 8.5 wet days
Daylight: 14 h 12 min; 5:14 AM – 7:27 PM
Cloud cover: 65%; 5th clearest
Wind: 13 km/h; 8th windiest
Solar energy: 4.06 kWh/m²
Travel score: 1.4; out of 10

← March Suomenlinna year-round climate May →Best places to visit in April

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 5°C in the first days to 11°C by the end.

A typical April day in Suomenlinna reaches about 8°C in the afternoon and slips back to 0°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 4°C and 13°C. Set against its neighbours, April runs about 7°C warmer than March and about 6°C cooler than May.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°C)	4	5	5	5	5	6	6	6	6	6	7	7	7	8	8	8	8	9	9	9	9	10	10	10	10	11	11	11	11	11
Avg low (°C)	-3	-2	-2	-2	-2	-2	-1	-1	-1	-1	-1	0	0	0	0	0	1	1	1	1	1	2	2	2	2	2	2	3	3	3

	Avg high (°C)	Avg low (°C)
1	4	-3
2	5	-2
3	5	-2
4	5	-2
5	5	-2
6	6	-2
7	6	-1
8	6	-1
9	6	-1
10	6	-1
11	7	-1
12	7	0
13	7	0
14	8	0
15	8	0
16	8	0
17	8	1
18	9	1
19	9	1
20	9	1
21	9	1
22	10	2
23	10	2
24	10	2
25	10	2
26	11	2
27	11	2
28	11	3
29	11	3
30	11	3

How April really feels in Suomenlinna

Once humidity and wind are folded in, April averages 0 days that feel above 32°C and 30 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C

heat index over the day's high

Days feeling ≤ 0°C

wind chill below the day's low

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

Suomenlinna weather by month

How April compares with the rest of the year at a glance. April is the 7th-warmest and 11th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	-2° / -7°	47	10.9	10.1	6.4	0.0
Feb	-3° / -8°	42	9.5	8.6	8.6	0.0
Mar	1° / -5°	36	8.4	7	11.3	0.0
Apr	8° / 0°	37	8.5	2.3	14.2	1.4
May	14° / 6°	46	9.3	0.1	16.8	4.3
Jun	19° / 11°	74	11.8	0	18.4	5.6
Jul	22° / 14°	78	12.1	0	17.7	6.3
Aug	20° / 13°	74	12	0	15.4	6.0
Sep	15° / 9°	58	10.5	0	12.6	4.4
Oct	9° / 4°	60	11.4	0.7	9.7	1.5
Nov	4° / 0°	58	11.6	4.4	7.1	0.0
Dec	0° / -4°	56	12.1	8.8	5.6	0.0

Cloud cover in April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 25% of the time in April.

Beyond those clear spells, partly cloudy skies cover about 16% of April, with mostly cloudy or overcast conditions the remaining 59%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	41	41	41	39	39	38	38	37	37	37	36	36	36	37	37	38	39	39	42	42	42	44	44	44	46	46	46	46	47	47
Cloudier (%)	59	59	59	61	61	62	62	63	63	63	64	64	64	63	63	62	61	61	58	58	58	56	56	56	54	54	54	54	53	53

	Clearer (%)	Cloudier (%)
1	41	59
2	41	59
3	41	59
4	39	61
5	39	61
6	38	62
7	38	62
8	37	63
9	37	63
10	37	63
11	36	64
12	36	64
13	36	64
14	37	63
15	37	63
16	38	62
17	39	61
18	39	61
19	42	58
20	42	58
21	42	58
22	44	56
23	44	56
24	44	56
25	46	54
26	46	54
27	46	54
28	46	54
29	47	53
30	47	53

Chance of precipitation in April

Any precipitationSnow

Suomenlinna gets around 37 mm of rain and snow over 8.5 wet days in April. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 28% and peaks near 29% on the wettest days, and about 2 days bring snow.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	28	28	28	28	28	28	28	28	28	28	28	28	28	28	27	28	28	28	28	28	28	28	29	29	29	29	29	29	29	29
Snow chance (%)	15	14	14	13	12	12	11	11	10	10	9	9	8	8	8	7	7	7	6	6	6	5	5	5	4	4	4	4	3	3

	Rain chance (%)	Snow chance (%)
1	28	15
2	28	14
3	28	14
4	28	13
5	28	12
6	28	12
7	28	11
8	28	11
9	28	10
10	28	10
11	28	9
12	28	9
13	28	8
14	28	8
15	27	8
16	28	7
17	28	7
18	28	7
19	28	6
20	28	6
21	28	6
22	28	5
23	29	5
24	29	5
25	29	4
26	29	4
27	29	4
28	29	4
29	29	3
30	29	3

Humidity in April

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, April lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

Wind in April

Winds average 13 km/h in April.

Across April, 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.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (km/h)	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	13	12	12	12	12	12	12	12	12	12
Feels	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze

	Wind speed (km/h)	Feels
1	13	light breeze
2	13	light breeze
3	13	light breeze
4	13	light breeze
5	13	light breeze
6	13	light breeze
7	13	light breeze
8	13	light breeze
9	13	light breeze
10	13	light breeze
11	13	light breeze
12	13	light breeze
13	13	light breeze
14	13	light breeze
15	13	light breeze
16	13	light breeze
17	13	light breeze
18	13	light breeze
19	13	light breeze
20	13	light breeze
21	13	light breeze
22	12	light breeze
23	12	light breeze
24	12	light breeze
25	12	light breeze
26	12	light breeze
27	12	light breeze
28	12	light breeze
29	12	light breeze
30	12	light breeze

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 48 min at the start of April to 15 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 162 minutes over April. Sunrise moves from 6:00 AM to 4:33 AM, and sunset from 6:49 PM to 8:02 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	12.8	12.9	13.0	13.1	13.2	13.3	13.4	13.5	13.6	13.7	13.8	13.8	13.9	14.0	14.1	14.2	14.3	14.4	14.5	14.6	14.7	14.8	14.9	14.9	15.0	15.1	15.2	15.3	15.4	15.5
Sunrise (AM)	6:00	5:57	5:54	5:51	5:48	5:45	5:41	5:38	5:35	5:32	5:29	5:26	5:23	5:20	5:17	5:14	5:11	5:08	5:05	5:02	4:59	4:56	4:53	4:50	4:47	4:44	4:41	4:39	4:36	4:33
Sunset (PM)	6:49	6:52	6:54	6:57	6:59	7:02	7:04	7:07	7:09	7:12	7:14	7:17	7:19	7:22	7:24	7:27	7:29	7:32	7:34	7:37	7:39	7:42	7:44	7:47	7:49	7:52	7:54	7:57	7:59	8:02

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	12.8	6:00	6:49
2	12.9	5:57	6:52
3	13.0	5:54	6:54
4	13.1	5:51	6:57
5	13.2	5:48	6:59
6	13.3	5:45	7:02
7	13.4	5:41	7:04
8	13.5	5:38	7:07
9	13.6	5:35	7:09
10	13.7	5:32	7:12
11	13.8	5:29	7:14
12	13.8	5:26	7:17
13	13.9	5:23	7:19
14	14.0	5:20	7:22
15	14.1	5:17	7:24
16	14.2	5:14	7:27
17	14.3	5:11	7:29
18	14.4	5:08	7:32
19	14.5	5:05	7:34
20	14.6	5:02	7:37
21	14.7	4:59	7:39
22	14.8	4:56	7:42
23	14.9	4:53	7:44
24	14.9	4:50	7:47
25	15.0	4:47	7:49
26	15.1	4:44	7:52
27	15.2	4:41	7:54
28	15.3	4:39	7:57
29	15.4	4:36	7:59
30	15.5	4:33	8:02

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 4.06 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 — April's 4.06 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	3.3	3.3	3.4	3.4	3.5	3.5	3.6	3.6	3.7	3.7	3.8	3.8	3.9	4.0	4.0	4.1	4.2	4.2	4.3	4.3	4.4	4.5	4.5	4.6	4.7	4.7	4.8	4.8	4.9	4.9
Level	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	3.3	Moderate
2	3.3	Moderate
3	3.4	Moderate
4	3.4	Moderate
5	3.5	Moderate
6	3.5	Moderate
7	3.6	Moderate
8	3.6	Moderate
9	3.7	Moderate
10	3.7	Moderate
11	3.8	Moderate
12	3.8	Moderate
13	3.9	Moderate
14	4.0	Moderate
15	4.0	Bright
16	4.1	Bright
17	4.2	Bright
18	4.2	Bright
19	4.3	Bright
20	4.3	Bright
21	4.4	Bright
22	4.5	Bright
23	4.5	Bright
24	4.6	Bright
25	4.7	Bright
26	4.7	Bright
27	4.8	Bright
28	4.8	Bright
29	4.9	Bright
30	4.9	Bright

Planning a trip in April

Is April a good time to visit Suomenlinna?

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

1.4

Sightseeing

7th-best month of the year

0.0

Beach & pool

6th-best month of the year

April is a weaker month for outdoor sightseeing in Suomenlinna.

What to pack for Suomenlinna in April

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

In April, Suomenlinna sees daytime highs around 8°C and nights near 0°C. Pack a warm layer. Worth having: a heavy coat and rain gear. About 9 days see rain.

a warm layera heavy coatrain gear

Sea temperature near Suomenlinna in April

The nearest coast averages about 2°C in April — 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.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sea temperature (°C)	2	1	1	2	6	11	16	17	14	10	7	4
Comfort	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Cool	Cool	Bracing	Bracing	Bracing	Bracing

	Sea temperature (°C)	Comfort
Jan	2	Bracing
Feb	1	Bracing
Mar	1	Bracing
Apr	2	Bracing
May	6	Bracing
Jun	11	Bracing
Jul	16	Cool
Aug	17	Cool
Sep	14	Bracing
Oct	10	Bracing
Nov	7	Bracing
Dec	4	Bracing

UV index in Suomenlinna in April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks around 3. 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.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	0	1	2	3	4	5	5	5	3	1	0	0
Level	Low	Low	Low	Moderate	Moderate	High	Moderate	Moderate	Moderate	Low	Low	Low

	UV index (midday)	Level
Jan	0	Low
Feb	1	Low
Mar	2	Low
Apr	3	Moderate
May	4	Moderate
Jun	5	High
Jul	5	Moderate
Aug	5	Moderate
Sep	3	Moderate
Oct	1	Low
Nov	0	Low
Dec	0	Low

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

water 77%

16 km

83 m

water 62%

80 km

193 m

water 50%

treesgrasslandcroplandartificial surfaceswater

← March Suomenlinna year-round climate May →Best places to visit in April

April 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

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).

	Avg high (°C)	Avg low (°C)
1	4	-3
2	5	-2
3	5	-2
4	5	-2
5	5	-2
6	6	-2
7	6	-1
8	6	-1
9	6	-1
10	6	-1
11	7	-1
12	7	0
13	7	0
14	8	0
15	8	0
16	8	0
17	8	1
18	9	1
19	9	1
20	9	1
21	9	1
22	10	2
23	10	2
24	10	2
25	10	2
26	11	2
27	11	2
28	11	3
29	11	3
30	11	3

	Clearer (%)	Cloudier (%)
1	41	59
2	41	59
3	41	59
4	39	61
5	39	61
6	38	62
7	38	62
8	37	63
9	37	63
10	37	63
11	36	64
12	36	64
13	36	64
14	37	63
15	37	63
16	38	62
17	39	61
18	39	61
19	42	58
20	42	58
21	42	58
22	44	56
23	44	56
24	44	56
25	46	54
26	46	54
27	46	54
28	46	54
29	47	53
30	47	53

	Rain chance (%)	Snow chance (%)
1	28	15
2	28	14
3	28	14
4	28	13
5	28	12
6	28	12
7	28	11
8	28	11
9	28	10
10	28	10
11	28	9
12	28	9
13	28	8
14	28	8
15	27	8
16	28	7
17	28	7
18	28	7
19	28	6
20	28	6
21	28	6
22	28	5
23	29	5
24	29	5
25	29	4
26	29	4
27	29	4
28	29	4
29	29	3
30	29	3

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

	Avg high (°C)	Avg low (°C)
1	4	-3
2	5	-2
3	5	-2
4	5	-2
5	5	-2
6	6	-2
7	6	-1
8	6	-1
9	6	-1
10	6	-1
11	7	-1
12	7	0
13	7	0
14	8	0
15	8	0
16	8	0
17	8	1
18	9	1
19	9	1
20	9	1
21	9	1
22	10	2
23	10	2
24	10	2
25	10	2
26	11	2
27	11	2
28	11	3
29	11	3
30	11	3

	Clearer (%)	Cloudier (%)
1	41	59
2	41	59
3	41	59
4	39	61
5	39	61
6	38	62
7	38	62
8	37	63
9	37	63
10	37	63
11	36	64
12	36	64
13	36	64
14	37	63
15	37	63
16	38	62
17	39	61
18	39	61
19	42	58
20	42	58
21	42	58
22	44	56
23	44	56
24	44	56
25	46	54
26	46	54
27	46	54
28	46	54
29	47	53
30	47	53

	Rain chance (%)	Snow chance (%)
1	28	15
2	28	14
3	28	14
4	28	13
5	28	12
6	28	12
7	28	11
8	28	11
9	28	10
10	28	10
11	28	9
12	28	9
13	28	8
14	28	8
15	27	8
16	28	7
17	28	7
18	28	7
19	28	6
20	28	6
21	28	6
22	28	5
23	29	5
24	29	5
25	29	4
26	29	4
27	29	4
28	29	4
29	29	3
30	29	3

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

	Avg high (°C)	Avg low (°C)
1	4	-3
2	5	-2
3	5	-2
4	5	-2
5	5	-2
6	6	-2
7	6	-1
8	6	-1
9	6	-1
10	6	-1
11	7	-1
12	7	0
13	7	0
14	8	0
15	8	0
16	8	0
17	8	1
18	9	1
19	9	1
20	9	1
21	9	1
22	10	2
23	10	2
24	10	2
25	10	2
26	11	2
27	11	2
28	11	3
29	11	3
30	11	3

	Clearer (%)	Cloudier (%)
1	41	59
2	41	59
3	41	59
4	39	61
5	39	61
6	38	62
7	38	62
8	37	63
9	37	63
10	37	63
11	36	64
12	36	64
13	36	64
14	37	63
15	37	63
16	38	62
17	39	61
18	39	61
19	42	58
20	42	58
21	42	58
22	44	56
23	44	56
24	44	56
25	46	54
26	46	54
27	46	54
28	46	54
29	47	53
30	47	53

	Rain chance (%)	Snow chance (%)
1	28	15
2	28	14
3	28	14
4	28	13
5	28	12
6	28	12
7	28	11
8	28	11
9	28	10
10	28	10
11	28	9
12	28	9
13	28	8
14	28	8
15	27	8
16	28	7
17	28	7
18	28	7
19	28	6
20	28	6
21	28	6
22	28	5
23	29	5
24	29	5
25	29	4
26	29	4
27	29	4
28	29	4
29	29	3
30	29	3

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100