Koper weather in May
Temperature, sea and sunshine in May: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in May
Poor
Best time to visit: June – August
What is the weather like in Koper in May?
In May, Koper is mild: daytime highs average 20 °C, and nights cool down to about 14 °C. The sea averages 18.0 °C – bracing, so a wetsuit helps for longer swims. The sun shines for around 8 hours a day. Rain is frequent, with about 13 rainy days and 106 mm in total. All in all, May is not an ideal month for a holiday in Koper.
May compared
How the weather changes from April to June. Tap a month to open it.
More details for May
- Daylight
- 14 h 52 min05:35 – 20:27
- UV index
- 8 · very highclear sky, noon (estimate)All months
- Muggy days
- 1 daydew point 18 °C or moreAll months
- Wind
- 15 km/haverage daily peakAll months
- Cloud cover
- 55 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+2Europe/Ljubljana
How the score comes together
- Temperatureweight 35 %15 %
- Seaweight 25 %14 %
- Sunshineweight 20 %87 %
- Few rainy daysweight 20 %39 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in May
- Wetsuit for longer swims
- Sunscreen
- Sunglasses & sun hat
- A jumper for the evenings
- Rain jacket or umbrella
Koper in May: quick answers
Is Koper hot in May?
No. In May, Koper is mild: daytime highs average 20 °C and nights drop to about 14 °C.
Can you swim in Koper in May?
Only if you don't mind cold water: in May the sea averages just 18.0 °C. Comfortable swimming is possible from June to September.
Does it rain much in Koper in May?
Rain is frequent, with about 13 rainy days and 106 mm in total.
Koper month by month
The whole year in KoperAll destinations: SloveniaWhere to go in MaySea temperature in May
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences