Koper Weather in May
Koper in May sees pleasant daytime temperatures of 21°C (70°F) and nighttime lows of 14°C (57°F). Rainfall is fairly high this month at around 109 mm (4.3 in), so pack a rain jacket to stay dry.
Rainfall in Koper in May
Typically around 14 days of rainfall are expected, averaging 109 mm (4.3 in) for the month. When it rains this month, it tends to come down fairly heavily. Showers can be substantial even if they don't last all day.
Temperature in Koper in May
May in Koper brings pleasant temperatures, with highs of 21°C (70°F) and nights around 14°C (57°F). The difference between afternoon and evening temperatures is usually noticeable. With overnight lows of 14°C (57°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep.
Sunshine in Koper in May
The days are predominantly sunny, with an estimated total of around 256 hours of sunshine. These sun-filled days are perfect for playing sports, visiting parks, or going for a bike ride.Should you favor a climate that's both dry and comfortably warm, June, July and August typically offer the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Slovenia, check out our Koper's climate page.
Koper Temperature in May
Min Temperature
14°C (57°F)
Max Temperature
21°C (70°F)
Chance of Rain
47%
Precipitation
109 mm (4.3 in)
Rainy days
14 days
Humidity
54% *
Sunshine
256 hours *
Percentage Sunshine
*
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Koper typically rise from around 20°C (68°F) at the start of May to approximately 24°C (75°F) by the end. Nights are cool, with lows typically ranging from 11°C (52°F) to 14°C (57°F).
Average temperatures in May
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in May
Historical weather for Koper in May
Browse day-by-day weather records for Koper spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Koper historical weather extremes in May
Our historical data for Koper spans 1976 to 2026, revealing these weather extremes.
- The warmest day in May was on May 28, 2003, with a maximum of 32°C (90°F).
- The lowest daytime temperature in May was 9°C (48°F), recorded on May 13, 1978.
- The coldest night in May in Koper was on May 1, 1976, with a minimum of 3°C (37°F).
- The wettest day in May Koper was on May 8, 2000 with 65 mm (2.6 in) of precipitation.
Best Places in Slovenia in May
Find out more about the weather in Slovenia and which places have the best travel conditions in this month. See all of Slovenia in May →
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What to Wear in Koper in May
Comfortable temperatures call for an easy wardrobe in May. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. Expect heavy rainfall, so bring good rain protection and waterproof bags. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.What To Do in Koper in May
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit Slovenia, check out our Koper's climate page.
Temperature Rainfall Sunshine Humidity
See the full Koper climate overview or explore weather in Slovenia.
