Koper weather in June

In June, Koper sees average daytime highs of 24°C and overnight lows near 18°C, with 85 mm of rain across 10.1 wet days and about 15.4 hours of daylight. It is the 3rd-warmest and 10th-wettest month of the year here.

Highs climb over the month, from about 23°C in the first days to 26°C by the end. The sky is clear or mostly clear about 46% of the time in June, and the air most often feels humid.

Daylight stretches from about 15 h 12 min at the start of June to 15 h 30 min by month's end. Set against the rest of the year, June is Koper's 3rd-clearest and 10th-windiest month. For the whole year in context, see Koper's year-round climate.

Daytime high
24°
3rd warmest
Overnight low
18°
10th coldest
Rainfall
85 mm
10.1 wet days
Daylight
15 h 30 min
4:21 AM – 7:49 PM
Cloud cover
46%
3rd clearest
Wind
9 km/h
10th windiest
Solar energy
6.41 kWh/m²
Travel score
7.0
out of 10

Koper is city in southwest Slovenia.

Air quality
Good
PM10 16.8 µg/m³ · 2019
Density
1,981/km²
people per km²

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

Temperature in June

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 23°C in the first days to 26°C by the end.

A typical June day in Koper reaches about 24°C in the afternoon and slips back to 18°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 28°C. Set against its neighbours, June runs about 4°C warmer than May and about 3°C cooler than July.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12216
22316
32316
42316
52317
62317
72317
82417
92417
102417
112417
122418
132418
142418
152418
162518
172518
182518
192518
202518
212519
222519
232519
242619
252619
262619
272619
282619
292619
302619

How June really feels in Koper

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

June sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Koper weather by month

How June compares with the rest of the year at a glance. June is the 3rd-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 779.10.98.91.1
Feb / 858.51.510.11.6
Mar12° / 869.30.711.63.3
Apr16° / 9511.20.213.24.8
May20° / 14°10311.7014.76.2
Jun24° / 18°8510.1015.47.0
Jul27° / 20°628.2015.17.2
Aug27° / 20°898.5013.97.1
Sep22° / 16°14710.3012.36.8
Oct18° / 12°15712.2010.75.5
Nov12° / 16712.70.39.33.1
Dec / 1129.90.98.61.5

Cloud cover in June

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 46% of the time in June.

Beyond those clear spells, partly cloudy skies cover about 21% of June, with mostly cloudy or overcast conditions the remaining 33%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16139
26139
36139
46139
56139
66139
76238
86238
96238
106337
116337
126535
136535
146634
156634
166634
176733
186832
196832
206931
216931
227030
237129
247129
257228
267228
277327
287426
297426
307525

Chance of precipitation in June

Any precipitation

Koper gets around 85 mm of rain over 10.1 wet days in June. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 33% and peaks near 39% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
137
237
338
438
539
639
739
839
938
1038
1138
1237
1336
1435
1535
1634
1733
1832
1932
2031
2130
2229
2328
2428
2528
2627
2727
2827
2927
3028

Humidity in June

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, June lands in the humid band about 38% of days. Sticky, muggy-or-worse air turns up on roughly 12% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
133382720
231372920
329373130
427363340
526363440
624353650
723353760
821353860
920343970
1019343980
1119334080
1218334090
13183240100
14173240110
15173140120
16173040120
17173040130
18182940140
19182839140
20182839151
21182739161
22182739161
23172639171
24172639181
25162639191
26162539201
27152539211
28142539211
29142539221
30132539231

Wind in June

Winds average 9 km/h in June.

Across June, daily wind ranges from about 8 km/h on the calmest days to 9 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
18calm
28calm
38calm
48calm
58calm
68calm
78calm
88calm
98calm
109calm
119calm
129calm
139calm
149calm
159calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
298calm
308calm

Sunrise & sunset in June

DaylightNight

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

Days grow by about 18 minutes over June. Sunrise moves from 4:26 AM to 4:24 AM, and sunset from 7:39 PM to 7:52 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
115.24:267:39
215.24:257:40
315.34:257:41
415.34:247:42
515.34:247:43
615.34:237:43
715.34:237:44
815.44:237:45
915.44:227:45
1015.44:227:46
1115.44:227:47
1215.44:227:47
1315.44:217:48
1415.54:217:48
1515.54:217:49
1615.54:217:49
1715.54:217:50
1815.54:217:50
1915.54:217:51
2015.54:217:51
2115.54:227:51
2215.54:227:51
2315.54:227:52
2415.54:227:52
2515.54:227:52
2615.54:237:52
2715.54:237:52
2815.54:237:52
2915.54:247:52
3015.54:247:52

Solar energy in June

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in June, about 6.41 kWh/m².

For context, solar energy here swings from a low near 1.2 kWh/m² to a high of 6.47 kWh/m² in July across the year — June's 6.41 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.2Intense
26.2Intense
36.2Intense
46.2Intense
56.3Intense
66.3Intense
76.3Intense
86.3Intense
96.3Intense
106.3Intense
116.3Intense
126.4Intense
136.4Intense
146.4Intense
156.4Intense
166.4Intense
176.5Intense
186.5Intense
196.5Intense
206.5Intense
216.5Intense
226.5Intense
236.5Intense
246.5Intense
256.5Intense
266.6Intense
276.6Intense
286.6Intense
296.6Intense
306.6Intense
Planning a trip in June

Is June a good time to visit Koper?

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

7.0
Sightseeing
3rd-best month of the year
6.1
Beach & pool
3rd-best month of the year

June is one of the better times to visit Koper for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Koper in June

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

In June, Koper sees daytime highs around 24°C and nights near 18°C. Pack sun protection. Worth having: light clothes and rain gear. About 10 days see rain.

sun protectionlight clothesrain gear

Sea temperature near Koper in June

The nearest coast averages about 23°C in June — 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 25°C and coldest in February near 10°C.

It's comfortable for a long swim from May 31 to Oct 9 — about 4.3 months when the water holds above 20°C.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan11Bracing
Feb10Bracing
Mar10Bracing
Apr13Bracing
May18Cool
Jun23Refreshing
Jul25Warm
Aug25Warm
Sep23Refreshing
Oct19Cool
Nov16Cool
Dec13Bracing

UV index in Koper in June

LowModerateHighVery highExtreme

Clear-sky midday UV in June peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Koper peaks around July 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 15UV 8Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr7High
May7High
Jun8Very high
Jul8Very high
Aug7Very high
Sep5Moderate
Oct3Moderate
Nov2Low
Dec1Low

Air quality in Koper in June

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where June falls, not just the annual average.

Air quality in Koper is worst in January — around 22 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (September, 12 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateJan 1822 µg/m³Sep 1412 µg/m³
PM2.5 (µg/m³)Level
Jan22Moderate
Feb20Moderate
Mar20Moderate
Apr19Moderate
May16Moderate
Jun16Moderate
Jul16Moderate
Aug13Moderate
Sep12Moderate
Oct14Moderate
Nov14Moderate
Dec18Moderate
Location & terrain

Where is Koper?

Koper sits at 45.5°N, 13.7°E, 12 m above sea level, in Slovenia. The nearest listed city is Trieste, 12 km away.

DivačaMonfalconeGoriziaPostojnaNova Gorica

Topography around Koper

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

Within 3 km, the terrain around Koper has only modest variations in elevation — a maximum elevation change of 238 m around an average of 24 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 575 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,150 m.

The land around Koper is covered by water (34%) and artificial surfaces (23%) within 3 km, trees (46%) and water (34%) within 16 km, and trees (48%) and water (29%) within 80 km.

3 km
238 m
16 km
575 m
80 km
2,150 m
treesshrubsgrasslandcroplandartificial surfaceswaterwetland
June weather nearby: Trieste 12 km · Piran 13 km · Divača 24 km · Monfalcone 32 km · Gorizia 44 km · Postojna 45 km · Nova Gorica 46 km · Rovinj 52 km

Slovenia travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / F
230 V · 50 Hz
Prices
≈ 63% of US
price level, 2025
GDP per capita
$37,376
2025
Happiness
6.9 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
0.6
per 100k, 2023
Road deaths
5.1
per 100k/yr, 2019
Income group
High
World Bank
Religion
Catholic 69%atheist 14%Orthodox 4%non-believer/agnostic 4%

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 Koper (45.5482°, 13.7296°, elevation 12 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).