Out of idle interest I just measured the temperature of our current "active" compost heap as I've not done so yet this year.
Temperatures today have been around 11°C most of the day, with a fairly stiff and cold easterly breeze. Not even the bumble bees have been flying. The compost heap however is rather toasty inside, at a smidge over 52°C. That's mainly garden and veggie plot waste, non-meat waste from the kitchen, some paper and cardboard, and grass clippings with some fallen leaves from last Autumn mixed in. I've also been putting in the occasional thin layer of scrapings from the area where we used to have our compost heaps about ten years ago that I'm clearing to make space for another greenhouse. It's fairly rich organic material with quite a few weeds (and almost certainly ungerminated seeds), so I'm putting it all through the compost to kill them all off.
James