The best period of the year to visit Slovenia is from July to September, in order to avoid the cold winter months and the rain season.
However, every season has its attractions in Slovenia. Snow can linger in the mountains until late June and even July, but spring is a great time to be in the lowlands and flower-carpeted valleys (though it can be pretty wet in May and June). At the same time the days are getting longer, the theatres and other cultural venues are in full swing, off-season rates still generally apply and local people are not yet jaded by waves of summer time visitors.
Slovenia gets most of its rain in the last spring (May and June) and autumn (October and November). January is the colder month, with an average annual temperature of -2 degree.
In general, Slovenia is temperate with four distinct seasons, but the topography creates three individual climates.
The Northwest has an alpine climate with strong influences from the Atlantic and abundant precipitation. Temperatures in the alpine valleys are moderate in summer but cold in winter.
The coast and a large part of Primorska as far as the Soca Valley has a Mediterranean climate with warm, sunny weather much of the year, and mostly mind winters.
Most eastern Slovenia has a Continental climate with hot summers and cold winters.