About Slovenia's weather - not essential to your holiday, but nice to know
Weather and Climate in Slovenia
Slovenia boasts three distinct climate types: Mediterranean, Continental and Alpine. The seasons are largely predictable - and you get a full set of four.
Spring - as in the rest of the world - can be unpredictable, but almost never as extreme as I used to describe spring weather in Britain: 'washing machine weather' (rinse, spin, tumble, wash, dry... repeat). If you want mostly sunny weather, mid April to June gets you the best of spring (and to my mind, the best of Slovenia). Also the best time for river sports, as the rivers are still full of snow-melt.
Summer averages between 20-30C and humidity is lower than it is in western Europe - much less windy too. Obviously it gets cooler the higher you go, but you'll only really feel the difference over 800 metres or so. Whatever altitude you get to, take your sun-block.
Autumn tends to be a gentle transformation from the heat of summer to the deep cold of winter. Plenty of early-morning mists, dazzling leaf-displays and a bit more rain. A great time to visit the mountains, when everything becomes kind of extra magical.
Winter starts around the beginning of December. There'll be a real nip in the air, and there might well be the first flurries of snow, even on the plains (there might not of course, but we have no 'in' with the snow gods). Temperatures on the flat bits tend to hang around minus five to plus ten, while the sharp, bumpy bits quite a bit lower than that. Snow usually starts up here and can get a tad deep (it was up to seven metres in Kranjska Gora in 2008!).
Weather in Slovenia right now...
... is probably better than where you are. Maybe. I don't know: we used to have a 'weather widget' here, but they're all unsecure and so can't be included in our website.