For compost to form, proper temperatures needed to be reached.
Ideally, you’d like to keep the temperature at 150 degrees for a few weeks. This is done by having the right balance of nitrogen, carbon, water and air.
The best way to tell what the temperature of your compost pile is is to use a compost thermoter
For $20, you can buy a special thermometer that will constantly tell you the core temp or your pile. For best results, you want 3 thermometers, one for the top, and two for the sides.
If your pile temp drops below 150, add more fresh grass clippings. The nitrogen will super charge the bacteria and boost the pile temp back up to the right range.
It’s important that the temp stay at or around 150, because it needs to kill the seeds in your grass, otherwise you’ll have tons of weeds springing up in your compost come springtime.
If the pile gets too hot, you can turn it, and add some water to help cool it down. You can also spread the pile out a bit to lower the core temp, but that’s usually not an issue. The most common problem is a pile that is too cool.