Climate and average weather in Flensburg

In Flensburg, the summers are mild, showery, and partly cloudy and the winters are cold, snowy, and mostly cloudy.

Best: late May to late September

Over the course of the year, the temperature in Flensburg typically varies from -0°C to 21°C, and is rarely below -7°C or above 27°C. July is the hottest month of the year, while January is the coldest.

Based on the travel score, the best time of year to visit Flensburg for warm-weather activities is from late May to late September.

Hottest
Jul
21°
Coldest
Jan
Wettest
Aug
76 mm
Driest
Apr
43 mm
Rain / yr
727 mm
139 wet days
Daylight
6.9–17.1 h
shortest–longest
Elevation
33 m
54.8°N
Clearest
May
61% cloud
Air quality
Moderate
PM2.5 11 µg/m³ · 2019

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

Flensburg weather by month, at a glance

The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.

Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around late May to late September.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Flensburg, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 3.6 months, from May 29 to September 14, with daily high temperatures above 17°C. The hottest month of the year in Flensburg is July, with an average high of 21°C and low of 13°C.

The cool season lasts 3.9 months, from November 19 to March 17, with daily high temperatures below 7°C. The coldest month of the year in Flensburg is January, with an average low of 0°C and high of 4°C.

Days typically run about 6°C warmer than nights, with the widest day–night swing (around 8°C) in May.

-10°10°20°30°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan40
Feb40
Mar71
Apr114
May168
Jun1911
Jul2113
Aug2113
Sep1711
Oct127
Nov84
Dec51

How hot and cold Flensburg really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the coldest nights, wind chill pulls the feels-like down to about -6°C (around January 30), with roughly 151 freezing days a year (feels-like at or below 0°C), worst in January.

-10°10°20°JanFebMarAprMayJunJulAugSepOctNovDec
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan44-50
Feb44-50
Mar77-31
Apr111104
May161658
Jun19191011
Jul21211313
Aug21211313
Sep17171011
Oct121247
Nov8804
Dec55-41

Average hourly temperature in Flensburg

A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on July afternoons, near 21°C, and coldest before dawn in January, near C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Flensburg weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 6412.72.77.60.0
Feb / -0°4910.43.39.30.0
Mar / 5010.7211.50.8
Apr11° / 439.60.313.72.9
May16° / 5510.6015.84.8
Jun19° / 11°6811.6016.95.7
Jul21° / 13°7412.3016.56.1
Aug21° / 13°7612.8014.76.0
Sep17° / 11°6311012.55.2
Oct12° / 6612.6010.23.1
Nov / 5711.90.68.21.1
Dec / 6312.62.67.10.0

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Flensburg gets about 727 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.

The wetter season lasts 1.7 months, from around Sep 28 to Nov 18, peaking in November at about 44% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Apr 15.

August is the wettest month by volume, with 76 mm over about 13 wet days; April is the driest, with 43 mm. Some of the cold-season precipitation falls as snow.

0%10%20%30%40%50%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetNov 4 · 44%Apr 15 · 30%
Rain on a day (%)Rain days
Jan4013
Feb3810
Mar3511
Apr3210
May3411
Jun3812
Jul4012
Aug4113
Sep3811
Oct4113
Nov4012
Dec4013

Monthly rainfall

Over a full year, Flensburg collects about 727 mm of rain across 139 wet days — roughly 61 mm in an average month.

It doesn’t fall evenly. August is the wettest month with 76 mm, while April is the driest at just 43 mm. The three wettest months alone bring about 30% of the year’s total, and some of the cold-season precipitation falls as snow.

0255075100JanFebMarAprMayJunJulAugSepOctNovDec644950435568747663665763
Rainfall (mm)Rain daysSnow days
Jan64133
Feb49103
Mar50112
Apr43100
May55110
Jun68120
Jul74120
Aug76130
Sep63110
Oct66130
Nov57121
Dec63133

Snow in Flensburg

Average snowy days through the year, the snow-season span, and estimated snowfall — for ski trips and the perennial 'will there be snow at Christmas?' question.

Flensburg averages about 12 snowy days a year. Snow season runs roughly Nov 14 to Apr 10 — about 4.9 months.

February is snowiest, with roughly 4 days of snow and an estimated 12 cm of snowfall. Over the year that adds up to an estimated 40 cm of snow.

0246JanFebMarAprMayJunJulAugSepOctNovDecsnow seasonsnow seasonFeb 4
Snow daysSnowfall (cm)
Jan39
Feb312
Mar28
Apr01
May00
Jun00
Jul00
Aug00
Sep00
Oct00
Nov12
Dec39

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Flensburg, the average share of the sky covered by clouds shows moderate seasonal variation over the course of the year.

The clearer part of the year begins around March 20 and lasts for 6.2 months, ending around September 23. The clearest month is May, when the sky is clear, mostly clear, or partly cloudy 44% of the time on average.

The cloudier part of the year begins around September 24 and lasts for 5.8 months, ending around March 19. The cloudiest month is December, when it is overcast or mostly cloudy 80% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecApr 19 · 45%Dec 4 · 19%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan2179
Feb2278
Mar2971
Apr4357
May4456
Jun3763
Jul4060
Aug3961
Sep3367
Oct2773
Nov2278
Dec2080

Daylight, sunrise and sunset

DaylightNight

Hours of daylight through the year, with sunrise and sunset times.

The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 21, brings about 17 h 06 min of light; the shortest, around December 21, only 6 h 54 min — a swing of roughly 10 h 12 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan7.68:464:17
Feb9.37:585:16
Mar11.56:486:15
Apr13.75:297:16
May15.84:248:13
Jun16.93:528:53
Jul16.54:128:44
Aug14.75:047:48
Sep12.56:036:30
Oct10.27:025:12
Nov8.28:054:10
Dec7.18:493:48

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Flensburg averages about 5 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 3 and 8 days.

The sunnier stretch runs 3.0 months, from around Mar 18 to Jun 16. The sunniest month is April, with roughly 8 sunny days (gloomy).

The greyest month is December, down near 3 sunny days — about 59% fewer than the April peak.

051015JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedApr 228 daysDec 13 days
Sunny daysSky
Jan4Gloomy
Feb3Gloomy
Mar5Gloomy
Apr7Gloomy
May8Gloomy
Jun6Gloomy
Jul7Gloomy
Aug6Gloomy
Sep5Gloomy
Oct4Gloomy
Nov3Gloomy
Dec3Gloomy

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.

Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.

In Flensburg, how humid it feels changes noticeably over the year.

The more humid part of the year lasts 2.9 months, from around June 17 to September 11. The muggiest month is August, when the air feels humid, muggy or worse about 15% of the time.

The most comfortable stretch runs from around September 12 to June 16, and May is the most comfortable month — the air is dry or comfortable 100% of the time.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecMay 3 · 100%Aug 2 · 82%humidcomfortabledrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)
Jan100000
Feb100000
Mar100000
Apr100000
May96400
Jun791830
Jul5137111
Aug4640141
Sep772120
Oct96400
Nov100000
Dec100000

Wind

Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Across the year, average wind speed in Flensburg is typically light breeze, near 16 km/h, and varies moderately with the seasons.

The windier part of the year lasts 5.6 months, from around Oct 17 to Apr 4. The windiest month is January, averaging about 18 km/h (light breeze).

The calmer part of the year runs from around Apr 5 to Oct 16, with July the calmest month at about 14 km/h.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezebreezyJan 8 · 18 km/hJul 29 · 13 km/h
Wind speed (km/h)Feels
Jan18light breeze
Feb17light breeze
Mar17light breeze
Apr15light breeze
May14light breeze
Jun15light breeze
Jul14light breeze
Aug14light breeze
Sep15light breeze
Oct16light breeze
Nov16light breeze
Dec17light breeze

Best time to visit Flensburg

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Flensburg throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around late May, Flensburg is still near the start of its best-weather window — great conditions with the peak-season crowds not yet at full swing.

Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.

The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Flensburg for general outdoor tourist activities is from late May to late September, with a peak score in the first week of August.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationAug 3 · 6.2

The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Travel score (0–10)Rating
Jan0.0poor
Feb0.0poor
Mar0.9poor
Apr2.9poor
May4.8fair
Jun5.7good
Jul6.1good
Aug6.0good
Sep5.1fair
Oct3.1poor
Nov1.1poor
Dec0.1poor

The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Flensburg for hot-weather activities is from mid July to late August, with a peak score in the first week of August.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationAug 1 · 4.2

The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

What to pack for Flensburg, by month

EssentialRecommendedOptional

Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.

For a warm-season trip around July (highs near 21°C), the essentials are rain gear and sun protection. In the cold season around January (highs near 4°C), pack a warm layer, a heavy coat and rain gear.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In July, Flensburg sees daytime highs around 21°C and nights near 13°C. Worth packing: rain gear and sun protection. About 12 days see rain.

Sea temperature near Flensburg

Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.

The sea at the nearest coast (about 45 km away) is warmest in August at about 19°C and coldest in February near 2°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
Jan3Bracing
Feb2Bracing
Mar3Bracing
Apr5Bracing
May11Bracing
Jun15Cool
Jul18Cool
Aug19Cool
Sep16Cool
Oct12Bracing
Nov9Bracing
Dec4Bracing

UV index (midday) in Flensburg by month

LowModerateHighVery highExtreme

Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.

Under clear skies, the midday UV index in Flensburg peaks around July 17 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 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJul 17UV 5Jan 1UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar2Moderate
Apr3Moderate
May5High
Jun5High
Jul5High
Aug5High
Sep4Moderate
Oct2Low
Nov1Low
Dec0Low

Average hourly UV index in Flensburg

LowModerateHighVery highExtreme

Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.

The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.

UV falls off far faster than brightness as the sun drops, so even in July the burn window is concentrated in the middle of the day: about 7 hours a day reach index 3 (protection recommended). Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan00
Feb00
Mar00
Apr20
May6.50
Jun70
Jul70
Aug60
Sep3.50
Oct00
Nov00
Dec00
Almanac & agriculture

Growing season

Chance of a frost-free dayTypical season (≥50%)

The growing season in Flensburg typically lasts about 329 days, from around February 24 to January 18 — the span where a frost-free day is more likely than not. It is reliably frost-free from April 14 to November 8.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecgrowing seasonFeb 2450%Apr 1490%Nov 890%Jan 1850%
Frost-free chance (%)Frost nights
Jan5031
Feb4828
Mar6431
Apr9016
May990
Jun1000
Jul1000
Aug1000
Sep1000
Oct970
Nov8224
Dec6031

Growing degree days

Degree days (base 10°C)Frost-free shaded

Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Flensburg banks about 754 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.

0200400600800JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan0
Feb0
Mar0
Apr0
May52
Jun140
Jul217
Aug217
Sep116
Oct13
Nov0
Dec0

Solar energy

Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Flensburg receives about 2.9 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 0.4 and 5.6 kWh/m².

The brighter stretch of the year lasts 5.7 months, from around Mar 24 to Sep 14. The brightest month is June, averaging about 5.5 kWh/m² (bright).

The dimmest month is December, down near 0.4 kWh/m² — roughly 92% less than the June peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseJun 65.6 kWhDec 200.4 kWh
Solar energy (kWh/m²)Level
Jan0.6Dim
Feb1.3Dim
Mar2.5Moderate
Apr4.2Bright
May5.3Bright
Jun5.5Bright
Jul5.3Bright
Aug4.3Bright
Sep2.8Moderate
Oct1.6Dim
Nov0.7Dim
Dec0.4Dim

Where is Flensburg?

Flensburg sits at 54.8°N, 9.4°E, 33 m above sea level, in Germany. The nearest listed city is Sønderborg, 26 km away.

HaderslevRendsburg

Topography around Flensburg

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

Within 3 km, the terrain around Flensburg has only modest variations in elevation — a maximum elevation change of 82 m around an average of 37 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 99 m; within 80 km, only modest variations in elevation — a maximum elevation change of 144 m.

The land around Flensburg is covered by trees (45%) and artificial surfaces (33%) within 3 km, cropland (39%), grassland (25%) and trees (22%) within 16 km, and water (35%), cropland (31%) and grassland (21%) within 80 km.

3 km
82 m
16 km
99 m
80 km
144 m
treesgrasslandcroplandartificial surfaceswaterwetland
Nearby: Sønderborg 26 km · Aabenraa 29 km · Schleswig 31 km · Tønder 40 km · Husum 42 km · Eckernförde 44 km · Haderslev 51 km · Rendsburg 56 km

Germany travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 80% of US
price level, 2025
GDP per capita
$60,496
2025
Happiness
6.9 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
0.9
per 100k, 2023
Road deaths
3.8
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 615
Religion
none 44%Roman Catholic 25%Protestant 23%other 5%

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 Flensburg (54.788°, 9.4372°, elevation 33 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).