Upvote:1
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.
https://www.mountain-forecast.com/peaks/Tre-Cime-di-Lavaredo/forecasts/2973
Hope for the best, prepare for the worse.
You need proper hiking equipment (boots, clothing ... ) and don't go out alone.