Slovenia is characterised by pronounced climatical differences on a short distance. Most of the country has a Continental climate. In the mountains, there is an Alpine climate. Closer to the coast, the climate is Sub-mediterranean. In general, weather forecasts are highly reliable but can be, in some cases, a few hours off. You can find the actual weather situation and forecasts on these websites:
It may also be helpful to check the actual weather on webcams, of which there are many. Links to webcams can be found here:
Summers can be warm in Slovenia, with temperatures reaching 30-35 °C during the daytime. At night, the temperature often drops to 20-25 °C. On hot days, sudden thunderstorms in the afternoon are common. These can be violent, but often don’t last long. Afterwards, the temperature is only a few degrees cooler but the humidity has markedly increased. There is a large difference between inland areas and the Slovenian coast: at the coast, it can be 5-10 degrees warmer. In the mountains, the difference between day- and night temperature is much more pronounced. Always check the weather forecast before going in the mountains, because every year some people are caught unprepared when the weather suddenly changes.
Winter weather is very variable, both from day to day and from year to year. In some years, there is a snow-cover which lasts several months. Other years, there is little snow in the lowland. Especially at night, the temperature often drops below zero. At higher altitudes, temperatures to minus 35 °C can be reached. At the coast, winters are much milder and snow lasts at most a few days.
Especially when the weather is changing, a very cold, strong wind can blow from the mountains to the coastal region, the Burja. At such times, motorway sections can be closed for trucks and mobile homes. This can be in any season.
Caves have a constant climate throughout the year. The temperature is around 12 °C with a close to 100% air humidity. Some caves have underground streams. After rain, the water level of these underground streams can rise quickly and some caves become temporarily inaccessible.
You should see the graphs below as a general indication for the entire country. Whenever you join our tours, you can be sure that we select the best areas in accordance to the season and forecasted weather.
You can do birdwatching throughout the year in Slovenia. There are two peak-seasons: springtime, when birds are singing and nesting, and autumn when many birds migrate through Slovenia. Especially for migratory birds, rainfall influences how easily they are seen. In wet years, the intermittent Lake Cerknica becomes an eldorado for waders and waterbirds, while in dry years they leave the area more quickly. Summertime is a silent season, when birds moult (grow new feathers) and don’t sing much.
In winter, few plants flower in Slovenia, but the first signs of spring can be as early as January. The end of March and beginning of April are good for a sudden flush of early spring flowers. By the middle of April, these early flowers are well past, but every day new species start flowering. Meadows are at their best in the second half of May and beginning of June. Mountain flowers start a bit later and are at their peak in June and July, depending on altitude. The end of September and beginning of October are again spectacular, when the whole forest becomes yellow and orange in the autumn.
It is not unusual to see single butterflies on sunny winter days, especially at the Slovenian coast. However, when you especially come for butterflies, May and June are the best months. Higher in the mountains, the season is later and July is better. However, different species have different flight-seasons and there are many butterflies throughout summer and into autumn. For most butterflies, sunny days with a minimum temperature of 15’C are required.
Many years, we have a bit of fun with the seasons and go to see wall lizards on the first of January. This is often possible on the Slovenian coast, even when inland temperatures are well below zero. However, I wouldn’t recommend winter as the best season for reptiles 🙂 Most amphibians and reptiles become active by the end of March, with several weeks of difference between species. Agile frogs and the endemic Italian agile frogs can start laying eggs already in February. For heat-loving Whipsnakes it is better to wait until May. Summer can be warm; many reptiles are then only visible in the early morning. Late autumn can be again very good for reptiles, but this depends on the temperature and this period may last as little as a week.
In principle, it is possible to see the Olm, the cave-salamander, throughout the year, because the underground temperature is constant. However, accessibility of caves and water clarity depend on rainfall. Especially when the snow melts in spring and after heavy autumn rain, you may have to postpone a cave-visit if you plan to see this species.
Hiking can be fantastic in mid-winter when it is possible to follow the tracks of mammals in the thick snow. However, for general hiking holidays, the season lasts from April to October. Regardless of the season, it is wise to check the weather forecast when you plan longer hikes.
The best season for hiking in Slovenia