When to go to Slovenia: it depends on what you want to see

Lakes and mountains: June to September

If you’re coming for Bled, Bohinj, the Julian Alps and the Soča, as most people are, the good window runs from June to September. Vintgar Gorge opens from April to October and Bled Castle keeps its long hours, 8am to 8pm, over the same months. The official statistics give a 20.2°C average in Ljubljana in June and 15.6°C in September, with the Alps a good deal cooler, as June at Rateče averages just 16°C. I’d choose September, for the light and the thinner crowds, and I explain why in Slovenia in September.

The coast: July and August

For the sea, heat is what counts. Portorož has the highest averages of the official stations, 23.6°C in July and 22.5°C in August. For the water itself I’d need an official reading of sea temperature, and I haven’t got one, so that number stays blank. The summer problem is different, the pressure on the Julian Alps, which the Tourist Board spelled out in May 2026 when it announced paid parking capped at 90 spaces on the Vršič Pass. If August is your month, get to Bled early and save the coast for the afternoons.

Skiing and Christmas: December to March

The Tourist Board counts some 230 km of pistes and 12 main resorts, with Mariborsko Pohorje the largest by length and Kanin, above Bovec, the highest, with natural snow well into spring. Opening and closing dates for 2026-27 weren’t on any official site when I looked, and I’d rather not guess. What does have a date is the Ptuj carnival, 3 to 9 February 2027, and the ski flying at Planica, 18 to 21 March 2027. If you’re driving, remember winter equipment is compulsory. It’s all in Slovenia in winter.

Once your dates are set, check which hotels are still free in Bled before prices climb.

Autumn, for the wine

Autumn is my second favourite. October still averages 11.5°C in Ljubljana and Vintgar stays open until the end of the month, while November brings St Martin’s Day, the new wine festival, celebrated in Maribor, Koper, Brda and Velenje according to the official calendar. The high mountains get trickier, but the wine regions are at their best.

The weather in numbers

The averages I use come from the official SURS table for 2001-2010, an old series but fine for comparing months. January is the coldest month in Ljubljana at 0.4°C and July the warmest. The full station-by-station table, rainfall included, is in Slovenia weather, and each month has its own page if you want detail, starting with Slovenia in January. By season, as well as winter, there are Slovenia in spring and Slovenia in autumn.

If you would rather have a local show you round, book a guided tour in Bled and choose by the reviews.

Once your dates are set, check which hotels are still free in Bled before prices climb.