During the summer, most plants wither and stop growing. It's also very dangerous to stay around in the base, because things keep smoldering up and you will probably not have enough ice in store to keep them cool.
While roaming the world, I noticed that mushrooms still appear to be growing, so I can pick them up as crock pot ingredients.
I just checked out the caves and it's still pretty hot in there, in addition to darkness for which I wasn't quite prepared and with all the grass bushes withered, I'm not sure how I can keep a stable supply of light sources.
With so little food and everything just waiting to burn to ashes, it doesn't look like there is going to be much "free" time.
But what else can I do when it's so hot all the time? Where can I find a safe place where the heat can't get me and my valuable items?