Mariehamn weather in December

In December, Mariehamn sees average daytime highs of 3°C and overnight lows near 1°C, with 56 mm of precipitation across 13 wet days and about 5.6 hours of daylight. It is the 9th-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 4°C in the first days to 2°C by the end. The sky is clear or mostly clear about 13% of the time in December, and the air most often feels dry.

Daylight stretches from about 6 h 06 min at the start of December to 5 h 36 min by month's end. Set against the rest of the year, December is Mariehamn's 10th-clearest and 1st-windiest month. For the whole year in context, see Mariehamn's year-round climate.

Daytime high
9th warmest
Overnight low
4th coldest
Precipitation
56 mm
13 wet days
Daylight
5 h 30 min
9:51 AM – 3:22 PM
Cloud cover
78%
10th clearest
Wind
30 km/h
1st windiest
Solar energy
0.18 kWh/m²
Travel score
0.0
out of 10

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 4°C in the first days to 2°C by the end.

A typical December day in Mariehamn reaches about 3°C in the afternoon and slips back to 1°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between -0°C and 6°C. Set against its neighbours, December runs about 3°C cooler than November and about 2°C warmer than January.

-5°10°151015202531
Avg high (°C)Avg low (°C)
153
242
342
442
542
642
742
842
942
1042
1142
1242
1341
1431
1531
1631
1731
1831
1931
2031
2131
2231
2330
2430
2530
2620
2720
2820
2920
3020
3120

How December really feels in Mariehamn

Once humidity and wind are folded in, December averages 0 days that feel above 32°C and 31 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
31
wind chill below the day's low

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

Mariehamn weather by month

How December compares with the rest of the year at a glance. December is the 9th-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / -1°4310.586.40.0
Feb / -2°297.76.58.60.0
Mar / -1°277.15.111.30.0
Apr / 296.91.714.20.0
May / 336.60.216.81.6
Jun13° / 11°497.5018.43.8
Jul17° / 15°487.6017.75.9
Aug18° / 16°5510.2015.45.8
Sep14° / 13°549.2012.64.1
Oct / 6211.80.49.81.9
Nov / 60132.97.10.4
Dec / 56136.15.60.0

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 13% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 11% of December, with mostly cloudy or overcast conditions the remaining 76%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
11981
21981
31981
41882
52080
62080
72179
82179
92179
102179
112278
122278
132377
142476
152575
162674
172773
182773
192872
202872
212872
222872
232872
242872
252773
262773
272773
282773
292773
302773
312674

Chance of precipitation in December

Any precipitationSnow

Mariehamn gets around 56 mm of rain and snow over 13 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 42% and peaks near 47% on the wettest days, and about 6 days bring snow.

0%20%40%60%151015202531
Rain chance (%)Snow chance (%)
14715
24615
34614
44514
54514
64414
74314
84315
94215
104216
114216
124217
134118
144119
154119
164120
174121
184122
194123
204123
214124
224224
234224
244225
254225
264124
274124
284124
294024
304023
314023

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

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

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

0%25%50%75%100%151015202531
Dry (%)
1100
2100
3100
4100
5100
6100
7100
8100
9100
10100
11100
12100
13100
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100
31100

Wind in December

Winds average 30 km/h in December, the windiest month of the year.

Across December, daily wind ranges from about 30 km/h on the calmest days to 30 km/h at its breeziest. It stays fairly steady from day to day.

0102030151015202531
Wind speed (km/h)Feels
130windy
230windy
330windy
430windy
530windy
630windy
730windy
830windy
930windy
1030windy
1130windy
1230windy
1330windy
1430windy
1530windy
1630windy
1730windy
1830windy
1930windy
2030windy
2130windy
2230windy
2330windy
2430windy
2530windy
2630windy
2730windy
2830windy
2930windy
3030windy
3130windy

Sunrise & sunset in December

DaylightNight

Daylight runs from about 6 h 06 min at the start of December to 5 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 30 minutes over December. Sunrise moves from 9:28 AM to 9:56 AM, and sunset from 3:32 PM to 3:31 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
16.19:283:32
26.09:303:31
36.09:323:30
45.99:333:29
55.99:353:28
65.89:373:27
75.89:393:26
85.89:403:25
95.79:423:25
105.79:433:24
115.69:453:24
125.69:463:23
135.69:473:23
145.69:483:23
155.59:503:22
165.59:513:22
175.59:523:22
185.59:523:22
195.59:533:22
205.59:543:23
215.59:543:23
225.59:553:24
235.59:553:24
245.59:563:25
255.59:563:25
265.59:563:26
275.59:563:27
285.59:563:28
295.59:563:29
305.69:563:30
315.69:563:31

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 0.18 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 0.18 kWh/m² to a high of 6.29 kWh/m² in June across the year — December's 0.18 kWh/m² sits near the bottom.

00.511.52151015202531
Solar energy (kWh/m²)Level
10.2Dim
20.2Dim
30.2Dim
40.2Dim
50.2Dim
60.2Dim
70.2Dim
80.2Dim
90.2Dim
100.2Dim
110.2Dim
120.2Dim
130.2Dim
140.2Dim
150.2Dim
160.2Dim
170.2Dim
180.2Dim
190.2Dim
200.2Dim
210.2Dim
220.2Dim
230.2Dim
240.2Dim
250.2Dim
260.2Dim
270.2Dim
280.2Dim
290.2Dim
300.2Dim
310.2Dim
Planning a trip in December

Is December a good time to visit Mariehamn?

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

0.0
Sightseeing
8th-best month of the year
0.0
Beach & pool
5th-best month of the year

December is a weaker month for outdoor sightseeing in Mariehamn.

What to pack for Mariehamn in December

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

In December, Mariehamn sees daytime highs around 3°C and nights near 1°C. Pack a warm layer and a windbreaker. Worth having: a heavy coat and rain gear. About 13 days see rain.

a warm layera windbreakera heavy coatrain gear

Sea temperature near Mariehamn in December

The nearest coast averages about 4°C in December — 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 February near 1°C.

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

0°5°10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan2Bracing
Feb1Bracing
Mar1Bracing
Apr3Bracing
May6Bracing
Jun11Bracing
Jul16Cool
Aug17Cool
Sep14Bracing
Oct10Bracing
Nov7Bracing
Dec4Bracing

UV index in Mariehamn in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 0. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Mariehamn peaks around June 18 at about 5 (high) — a little sun protection helps at midday. It bottoms out near December 20 at about 0 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateModerateLowJun 18UV 5Dec 20UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar1Low
Apr3Moderate
May4Moderate
Jun5High
Jul5Moderate
Aug4Moderate
Sep3Moderate
Oct1Low
Nov0Low
Dec0Low
Location & terrain

Where is Mariehamn?

Mariehamn sits at 60.1°N, 19.9°E, 11 m above sea level, in Aland Islands. The nearest listed city is Norrtälje, 78 km away.

Topography around Mariehamn

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

Within 3 km, the terrain around Mariehamn has only modest variations in elevation — a maximum elevation change of 55 m around an average of 7 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 80 m; within 80 km, only modest variations in elevation — a maximum elevation change of 130 m.

The land around Mariehamn is covered by water (44%) and trees (32%) within 3 km, water (55%) and trees (31%) within 16 km, and water (86%) within 80 km.

3 km
55 m
16 km
80 m
80 km
130 m
treesgrasslandcroplandartificial surfaceswaterwetland
December weather nearby: Norrtälje 78 km · Åkersberga 114 km · Vallentuna 121 km · Gustavsberg 122 km · Naantali 122 km · Boo 126 km · Täby 127 km · Märsta 128 km

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Mariehamn (60.0973°, 19.9348°, elevation 11 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).