Too hot?

Today was a beautiful day, one of a series. Temperatures above 10°C, again. Obviously too hot for someone.
I saw this jacket hanging in the middle of a forest, no-one apart from me visible. And it is still winterly, so I can see quite far through the forest; no big/thick trees blocking my sight.
So someone must have left the jacket there. Perhaps forgotten? Or too hot to carry.
Thanks to Marlieske for hosting the Derelict Sunday challenge.