Climate and average weather in Koszalin

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

Best: late May to late September

Over the course of the year, the temperature in Koszalin typically varies from -1°C to 22°C, and is rarely below -9°C or above 27°C. August is the hottest month of the year, while January is the coldest.

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

Hottest
Aug
22°
Coldest
Jan
-1°
Wettest
Jul
90 mm
Driest
Apr
38 mm
Rain / yr
726 mm
140 wet days
Daylight
7.1–16.9 h
shortest–longest
Elevation
30 m
54.2°N
Clearest
May
56% cloud

Koszalin is city with powiat rights of Poland.

Air quality
Moderate
PM2.5 13.7 µg/m³ · 2019
Density
1,023/km²
people per km²
Founded
1266

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

Koszalin 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 Koszalin, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 3.7 months, from May 28 to September 16, with daily high temperatures above 17°C. The hottest month of the year in Koszalin is August, with an average high of 22°C and low of 14°C.

The cool season lasts 3.8 months, from November 20 to March 16, with daily high temperatures below 6°C. The coldest month of the year in Koszalin is January, with an average low of -1°C and high of 2°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)
Jan2-1
Feb3-1
Mar60
Apr114
May168
Jun1912
Jul2114
Aug2214
Sep1811
Oct127
Nov73
Dec40

How hot and cold Koszalin 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 -8°C (around January 26), with roughly 158 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)
Jan22-7-1
Feb33-7-1
Mar66-40
Apr111104
May161658
Jun19191112
Jul21211414
Aug22221414
Sep18181011
Oct121247
Nov77-13
Dec34-50

Average hourly temperature in Koszalin

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 August afternoons, near 22°C, and coldest before dawn in January, near -1°C.

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

Koszalin 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 / -1°5411.74.57.70.0
Feb / -1°4410.24.59.30.0
Mar / 4910.3311.50.6
Apr11° / 3890.513.73.0
May16° / 5610.80.115.75.0
Jun19° / 12°7112016.85.8
Jul21° / 14°9013.3016.46.1
Aug22° / 14°7813.4014.66.1
Sep18° / 11°6812.2012.55.2
Oct12° / 6612.50.110.23.1
Nov / 5311.81.38.20.8
Dec / 5812.447.20.0

Chance of rain

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

Koszalin gets about 726 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 3.3 months, from around Jun 9 to Sep 16, peaking in September at about 49% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Apr 22.

July is the wettest month by volume, with 90 mm over about 13 wet days; April is the driest, with 38 mm. Some of the cold-season precipitation falls as snow.

0%10%20%30%40%50%60%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetSep 1 · 49%Apr 22 · 28%
Rain on a day (%)Rain days
Jan3712
Feb3710
Mar3310
Apr309
May3511
Jun4012
Jul4213
Aug4313
Sep4112
Oct4013
Nov4012
Dec4012

Monthly rainfall

Over a full year, Koszalin collects about 726 mm of rain across 140 wet days — roughly 60 mm in an average month.

It doesn’t fall evenly. July is the wettest month with 90 mm, while April is the driest at just 38 mm. The three wettest months alone bring about 33% of the year’s total, and some of the cold-season precipitation falls as snow.

0255075100125JanFebMarAprMayJunJulAugSepOctNovDec544449385671907868665358
Rainfall (mm)Rain daysSnow days
Jan54125
Feb44105
Mar49103
Apr3891
May56110
Jun71120
Jul90130
Aug78130
Sep68120
Oct66130
Nov53121
Dec58124

Snow in Koszalin

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.

Koszalin averages about 18 snowy days a year. Snow season runs roughly Nov 5 to Apr 17 — about 5.4 months.

February is snowiest, with roughly 5 days of snow and an estimated 21 cm of snowfall. Over the year that adds up to an estimated 69 cm of snow.

02468JanFebMarAprMayJunJulAugSepOctNovDecsnow seasonsnow seasonFeb 16
Snow daysSnowfall (cm)
Jan517
Feb521
Mar310
Apr12
May00
Jun00
Jul00
Aug00
Sep00
Oct00
Nov15
Dec414

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

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

The clearer part of the year begins around March 22 and lasts for 6.2 months, ending around September 27. The clearest month is May, when the sky is clear, mostly clear, or partly cloudy 51% of the time on average.

The cloudier part of the year begins around September 28 and lasts for 5.7 months, ending around March 21. The cloudiest month is December, when it is overcast or mostly cloudy 82% 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 26 · 52%Dec 10 · 16%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan2377
Feb2575
Mar3466
Apr4753
May5149
Jun4753
Jul4951
Aug4753
Sep3961
Oct3070
Nov2080
Dec1882

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 14, brings about 16 h 54 min of light; the shortest, around December 14, only 7 h 06 min — a swing of roughly 9 h 48 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan7.78:153:54
Feb9.37:294:51
Mar11.56:215:49
Apr13.75:036:48
May15.73:597:44
Jun16.83:298:22
Jul16.43:488:14
Aug14.64:397:19
Sep12.55:376:02
Oct10.26:344:47
Nov8.27:353:46
Dec7.28:183:25

Sunny days

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

Koszalin averages about 6 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 2 and 10 days.

The sunnier stretch runs 5.9 months, from around Mar 20 to Sep 15. The sunniest month is April, with roughly 9 sunny days (mixed).

The greyest month is December, down near 3 sunny days — about 72% fewer than the April peak.

051015JanFebMarAprMayJunJulAugSepOctNovDecgreyersunniergreyergloomymixedApr 2410 daysDec 72 days
Sunny daysSky
Jan4Gloomy
Feb4Gloomy
Mar6Gloomy
Apr9Mixed
May10Mixed
Jun8Mixed
Jul9Mixed
Aug8Mixed
Sep6Gloomy
Oct5Gloomy
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 Koszalin, how humid it feels changes dramatically over the year.

The more humid part of the year lasts 2.8 months, from around June 18 to September 11. The muggiest month is August, when the air feels humid, muggy or worse about 20% of the time.

The most comfortable stretch runs from around September 12 to June 17, and April 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%JanFebMarAprMayJunJulAugSepOctNovDecApr 30 · 100%Aug 1 · 70%humidcomfortabledrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)
Jan100000
Feb100000
Mar100000
Apr100000
May94510
Jun732250
Jul3743183
Aug3743183
Sep781930
Oct97300
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 Koszalin is typically light breeze, near 17 km/h, and varies moderately with the seasons.

The windier part of the year lasts 5.9 months, from around Sep 30 to Mar 27. The windiest month is January, averaging about 19 km/h (light breeze).

The calmer part of the year runs from around Mar 28 to Sep 29, with July the calmest month at about 14 km/h.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezebreezyJan 6 · 20 km/hJul 31 · 13 km/h
Wind speed (km/h)Feels
Jan19light breeze
Feb19light breeze
Mar17light breeze
Apr15light breeze
May14light breeze
Jun15light breeze
Jul14light breeze
Aug14light breeze
Sep16light breeze
Oct17light breeze
Nov18light breeze
Dec19light breeze

Best time to visit Koszalin

TravelBeach/poolTemperatureCloudsPrecipitation

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

Around late May, Koszalin 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 Koszalin 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 2 · 6.4

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
Mar0.6poor
Apr3.0poor
May4.9fair
Jun5.8good
Jul6.1good
Aug6.1good
Sep5.2fair
Oct3.1poor
Nov0.8poor
Dec0.0poor

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 Koszalin 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 2 · 4.7

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 Koszalin, 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 August (highs near 22°C), the essentials are rain gear and sun protection. In the cold season around January (highs near 2°C), pack a warm layer, a heavy coat and rain gear.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In August, Koszalin sees daytime highs around 22°C and nights near 14°C. Worth packing: rain gear and sun protection. About 13 days see rain.

Sea temperature near Koszalin

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 20 km away) is warmest in August at about 19°C and coldest in February near 3°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
Jan4Bracing
Feb3Bracing
Mar3Bracing
Apr5Bracing
May9Bracing
Jun14Bracing
Jul17Cool
Aug19Cool
Sep16Cool
Oct13Bracing
Nov9Bracing
Dec6Bracing

UV index (midday) in Koszalin 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 Koszalin peaks around June 17 at about 6 (high) — sunscreen and a hat are worth it in the middle of the day. 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 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJun 17UV 6Dec 20UV 0
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May5High
Jun6High
Jul5High
Aug5High
Sep4Moderate
Oct2Low
Nov1Low
Dec0Low

Average hourly UV index in Koszalin

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 June the burn window is concentrated in the middle of the day: about 7.5 hours a day reach index 3 (protection recommended), and 1 hours reach 6 or more. 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
Apr40
May6.50
Jun7.51
Jul70
Aug60
Sep30
Oct00
Nov00
Dec00

Air quality in Koszalin by month

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.

Air quality in Koszalin is worst in April — around 18 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (December, 8 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to Koszalin's WHO annual average of 13.7 µg/m³.

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodApr 1318 µg/m³Dec 149 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar17Moderate
Apr18Moderate
May16Moderate
Jun16Moderate
Jul16Moderate
Aug15Moderate
Sep14Moderate
Oct11Good
Nov9Good
Dec8Good
Almanac & agriculture

Growing season

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

The growing season in Koszalin typically lasts about 282 days, from around March 10 to December 16 — the span where a frost-free day is more likely than not. It is reliably frost-free from April 18 to November 7.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecgrowing seasonMar 1050%Apr 1890%Nov 790%Dec 1650%
Frost-free chance (%)Frost nights
Jan3831
Feb3828
Mar5531
Apr8819
May990
Jun1000
Jul1000
Aug1000
Sep1000
Oct970
Nov8125
Dec5131

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. Koszalin banks about 831 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.

02004006008001,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan0
Feb0
Mar0
Apr0
May59
Jun157
Jul239
Aug240
Sep124
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.

Koszalin receives about 3.0 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 0.4 and 5.9 kWh/m².

The brighter stretch of the year lasts 5.8 months, from around Mar 23 to Sep 14. The brightest month is June, averaging about 5.8 kWh/m² (bright).

The dimmest month is December, down near 0.5 kWh/m² — roughly 92% less than the June peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseJun 35.9 kWhDec 190.4 kWh
Solar energy (kWh/m²)Level
Jan0.6Dim
Feb1.4Dim
Mar2.6Moderate
Apr4.4Bright
May5.5Bright
Jun5.8Bright
Jul5.5Bright
Aug4.5Bright
Sep3.0Moderate
Oct1.6Dim
Nov0.8Dim
Dec0.4Dim

Where is Koszalin?

Koszalin sits at 54.2°N, 16.2°E, 30 m above sea level, in Poland. The nearest listed city is Białogard, 24 km away.

KołobrzegŚwidwinUstkaSłupskSzczecinekGryficeBytów

Topography around Koszalin

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

Within 3 km, the terrain around Koszalin has only modest variations in elevation — a maximum elevation change of 106 m around an average of 39 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 153 m; within 80 km, significant variations in elevation — a maximum elevation change of 264 m.

The land around Koszalin is covered by artificial surfaces (38%) and trees (35%) within 3 km, trees (38%), cropland (23%) and grassland (20%) within 16 km, and trees (38%), water (27%) and cropland (22%) within 80 km.

3 km
106 m
16 km
153 m
80 km
264 m
treesgrasslandcroplandartificial surfaceswaterwetland
Nearby: Białogard 24 km · Kołobrzeg 38 km · Świdwin 53 km · Ustka 62 km · Słupsk 63 km · Szczecinek 64 km · Gryfice 71 km · Bytów 86 km

Poland travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / E
230 V · 50 Hz
Prices
≈ 52% of US
price level, 2025
GDP per capita
$28,420
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
89%
of population, 2024
Homicide rate
0.8
per 100k, 2023
Road deaths
9.4
per 100k/yr, 2019
Income group
High
World Bank
English
Very high
EF EPI 600
Religion
Roman Catholic 71%refused to answer 21%no religion 7%

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 Koszalin (54.1944°, 16.1722°, elevation 30 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).