I will be doing some hiking in Alpe Di Siusi and Tre Cime from Sept 18 to 22. Is September still a warm sunny month? Or is it going to be colder?
Also,this may sound silly but are there any poisonous snakes in these areas I mentioned?
It is a mountain area, there is always risk of cold weather and snow, even in early fall when in high altitude.
Currently the weather around Tre Cime is on the colder sider with freezing temperature at night.
Hope for the best, prepare for the worse.
You need proper hiking equipment (boots, clothing ... ) and don't go out alone.