Sežana Weather in September

September in Sežana brings high temperatures around 22°C (72°F) during the day, dropping to 14°C (57°F) at night, and as part of the rainy season, heavy rainfall is common.

Rainfall in Sežana in September

As part of the rainy season, Sežana sees around 12 days of rain in September, with an average of 176 mm (6.9 in). Rainy season showers tend to be fairly substantial. A good rain jacket or umbrella is worth having with you most days.

Temperature in Sežana in September

Daytime highs in Sežana in September reach 22°C (72°F), with nights around 14°C (57°F). Conditions stay fairly consistent through the month, making it easier to plan what to wear. Nights cool down to 14°C (57°F), so a light jacket or extra layer is useful once the sun goes down. On the plus side, the cooler nights make for comfortable sleeping conditions.

Sunshine in Sežana in September

Expect sunny days throughout the month, with an estimated 211 hours of sunshine. Despite being the rainy season, it could still be a nice time to visit. Rain often arrives later in the day, keeping most of the days sunny.

Average water temperature in September

With water at 22°C (72°F), you can expect warm, pleasant conditions for any water activity. There's no adjustment period — it feels comfortable straight away.

If you prefer dry days with pleasant temperatures, July typically offers the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.

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For a detailed overview over the year and the best time to visit Slovenia, check out our Sežana's climate page.

Sežana Temperature in September

Min Temperature 14°C (57°F)  

Max Temperature 22°C (72°F)  

Water Temperature 22°C (72°F) *  

Chance of Rain 41%  

Precipitation 176 mm (6.9 in)  

Rainy days 12 days  

Humidity 67% *  

Sunshine 211 hours *  

Percentage Sunshine 54% *  

* Data from: Triest, Italy (11 KM, 7 Miles).

Daily Historical Temperatures

50-year average (1976-2025)

Based on our historical records, temperatures in Sežana typically drop from around 26°C (79°F) at the start of September to approximately 22°C (72°F) by the end. Nights are pleasant, with lows typically ranging from 13°C (55°F) to 16°C (61°F).

Average temperatures in September

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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 September

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Historical weather for Sežana in September

Browse day-by-day weather records for Sežana spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.

Historical weather Temperatures Precipitation

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Sežana historical weather extremes in September

Based on 49 years of weather observations (1976-2025), these are the most extreme conditions recorded in Sežana.

• The hottest September day on record in Sežana reached 35°C (95°F) (September 23, 1985).
• On September 18, 1977, Sežana saw its coldest September day with temperatures maxing out at 11°C (52°F).
• Nighttime temperatures dropped to 4°C (39°F) on September 29, 1977, marking the coldest September night on record.

What to Wear in Sežana in September

Comfortable temperatures call for an easy wardrobe in September. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. It's going to pour! Pack a good poncho and prepare for very wet conditions. The water temperature sits at about 22°C (72°F), making it perfect for swimming and water activities. Don't forget to pack your favorite swimwear and perhaps some snorkel gear. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.

What To Do in Sežana in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

7/10

Camping

6/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Slovenia, check out our Sežana's climate page.

More climate data for Sežana

Temperature Rainfall Sunshine Humidity Water Temp

See the full Sežana climate overview or explore weather in Slovenia.