My compost pile is too cool
I have an Earth Machine, and I started composting in it a month ago, at the end of January. (Remember I'm in Phoenix, so it was in the 60's in the afternoon then, and it's in the 80's in the afternoon now.)
When I started I had nothing but dried leaves, and over the past month I've been adding all of our fruit and vegetable peelings and ends. I haven't added any grass clippings because we haven't cut the lawn.
At first I was adding green materials and mixing it up daily, but after asking about frequent turning here, I've been saving up the green materials and adding them every two to three days.
I always try to keep the pile the wetness of a wrung-out sponge.
For the first few weeks, I could feel that the center of the pile was very warm, but lately it hasn't felt very warm. I got a composting thermometer yesterday, and it read exactly 80 -- the very lowest reading before the materials are too cool to break down into compost.
Why is my compost pile too cool?