worldweather31°Cexceptionally warm
usually 22°C–27°C
warmer than 99% of similar days
night: exceptionally warm
rain: typical rainfall
wind: exceptionally light
Weather in Koper - 14-day forecast
Detailed weather forecast for Koper, Slovenia: daytime and night temperature, rain, sunrise and sunset - today and for the next two weeks.
Forecast for the next days in Koper
today🌧️
31°💧 0.1 mm
Sun☀️
30°💧 0.9 mm
Mon☀️
31°💧 0.2 mm
Tue🌧️
32°💧 0.2 mm
Wed🌧️
28°💧 11.3 mm
Thu🌧️
18°💧 40.5 mm
Fri☁️
26°💧 3 mm
Sat☁️
26°💧 3.8 mm
Forecast vs 1991-2020 climate normal
NASA POWERHow does the current forecast compare with normal?
We compare the coming days with weather usually observed at this time of year.
Sunday 6 Sept in Koper, the forecast high is 30°C. Typical daytime temperatures at this time of year range from 21°C to 26°C, so it will be exceptionally warm. It is warmer than 100% of similar days.
30°Cexceptionally warm
usually 21°C–26°C
warmer than 100% of similar days
night: exceptionally warm
rain: typical rainfall
wind: lighter than usual
31°Cexceptionally warm
usually 21°C–26°C
warmer than 99% of similar days
night: exceptionally warm
rain: typical rainfall
wind: lighter than usual
32°Cexceptionally warm
usually 21°C–26°C
warmer than 99% of similar days
night: exceptionally warm
rain: typical rainfall
wind: exceptionally light
28°Cexceptionally warm
usually 21°C–26°C
warmer than 95% of similar days
night: exceptionally warm
rain: exceptionally wet
wind: exceptionally light
18°Cexceptionally cool
usually 21°C–26°C
cooler than 95% of similar days
night: near normal
rain: exceptionally wet
wind: typical
26°Cwarmer than usual
usually 21°C–26°C
warmer than 82% of similar days
night: exceptionally warm
rain: more rain than usual
wind: lighter than usual
How warm was this week in previous years?
Each bar shows the average daily high during the same 7-day period in each year.
cooler yearstypical rangewarmer years2026 forecastcurrent forecast
From 1981 to 2025, the 5-11 Sept period averaged 24°C by day. The coolest year was 1996 (20°C) and the warmest was 2008 (27°C). The current forecast averages 28°C - higher than in 100% of historical years.
Historical reference: NASA POWER daily gridded data (MERRA-2), the 1991-2020 normal and a +/- 7-day calendar window. The typical range is the 20th-80th percentile. This is not a city weather-station reading and does not change the current forecast. NASA POWER Daily API.
Weather warnings - Koper
No active weather warnings for Koper (region: Southwest). The national weather service is not forecasting dangerous conditions.
14-day forecast - Koper
Koper 30 & 45-day weather - long-range outlook
Next 16 days · forecast
27°
around 21° at night · days with rain: 8
Weeks 3-4 · avg for September
25°
around 15° at night · rain chance 31%
Weeks 5-7 · avg for October
19°
around 11° at night · rain chance 48%
The 30 & 45-day outlook for Koper: the next 16 days are a numerical forecast updated daily - on average 27° by day and 21° at night. Further out we rely on multi-year climate averages: around 25° in September, and about 19° in October. Forecasts beyond two weeks are indicative only.
Day-by-day forecast for Koper
Saturday5 September 2026
🌧️31°light rain
Sunday6 September 2026
☀️30°clear sky
Monday7 September 2026
☀️31°clear sky
Tuesday8 September 2026
🌧️32°light rain
Wednesday9 September 2026
🌧️28°moderate rain
Thursday10 September 2026
🌧️18°heavy rain
Friday11 September 2026
☁️26°overcast clouds
Saturday12 September 2026
☁️26°overcast clouds
Sunday13 September 2026
🌧️24°light rain
Monday14 September 2026
🌤️26°a few clouds
Tuesday15 September 2026
☀️27°clear sky
Wednesday16 September 2026
🌧️26°light rain
Thursday17 September 2026
🌧️26°moderate rain
Friday18 September 2026
☀️27°clear sky
Saturday19 September 2026
☀️29°clear sky
Sunday20 September 2026
☀️28°clear sky
UV index in Koper - is it safe to sunbathe?
Today the UV index in Koper is 6 (moderate) - unprotected fair skin can burn in about 35 minutes. Seek shade around midday. SPF 30+, sunglasses and a hat for longer stays.
Pollen in Koper - info for allergy sufferers
Today ragweed pollen is highest in Koper - about 36 grains/m³, high level. Allergy sufferers should limit time outdoors on dry, windy days and take medication as advised. Pollen levels are a CAMS model forecast and are indicative.
Sea temperature - Koper
Water today
27°C
Week avg
27°C
Waves today
0.1 m
How's the water?
very warm
16-day sea temperature forecast:
Average sea temperature through the year:
Sea-surface temperature from marine models, updated daily. See also: where the sea is warmest right now.
Koper weather through the year
Warmest, driest months on average: April, May, June, July.
Upcoming public holidays in Slovenia: Reformation Day — 31 October · Day of the Dead — 1 November · Christmas Day — 25 December.
Nearby and related places
FAQ - Koper weather
What is the weather like in Koper today?
Today it is about 31° during the day and 23° at night, light rain.
How far ahead can I check the forecast for Koper?
This page shows a detailed 14-day forecast plus the long-term monthly climate, so you can plan both a short trip and a holiday months ahead.