I want to be able to start a hot compost pile December 20th and have it go the winter but I'm not sure if it'll be too cold to start one. That'd be cool.

I don't think it is ever too cold to start a compost pile, well, right now, everything is so frozen solid that nothing would pile together at all! But go for it, I have never been in a hurry with my compost, the fastest mine ever cooked up was when I added some maggot-laden llama manure.

i wonder if you could start it up by dumping hot water on it all

How long does it take hot water to freeze ??? I don't know if it would be worth the time, trouble and effort to advertise on freecycle for an electric blanket to cover your tumbler with and set it on high. ":^) Then there would be the cost of the electricity. I am sure that if you did that you would have to keep it dry to prevent dangerous electrical shock.

Our weather has become colder, sooner than usual with some frozen rain, sleet and snow then lows around 21 degrees, a brief warm up, then back to about 21 this morning. The sudden cold really dammaged my winter greens but has not hurt my compost pile. I have had a small pile started from shredding a little bit of old hay and a few leaves, along with the spent plants from the garden. It has been cooking some as I have continued to dump my kitchen scrap bucket into it. Thanksgiving day, my sis in law brought me a pick up bed {{gwi:315920}} of green horse manure mixed with thin wood shavings and some alfalfa hay bits. I filled up my hot bed and dumped a couple of muck buckets of the mixture on my compost pile. A few days later it was {{gwi:315922}}.

I then ran my tiller into the pile to grind and mix it up a {{gwi:259064}} and then layered on the pile a mixture fruits, veggies and {{gwi:319348}}. I then piled it back up and covered it with some more {{gwi:319349}}. Early yesterday morning when the temps were just over 20* I checked the temprature of the pile and it looks like it was about {{gwi:318246}} at this spot. This morning it was 150*, so it is heating up fine. In our climate I should have no problems keeping it cooking till it is done in a month or two.
Bill P.

"How long does it take hot water to freeze ???"

It never freezes. It only freezes if it cools off, but then it wouldn't be "hot water" any longer. ;>)

Adding hot water to the pile wouldn't help make it a hot compost pile in the way you want it to be a hot compost pile.

The heat of a hot compost pile comes from the microbial activity. If the pile is large enough, has enough oxygen and water (but not too much), is turned periodically and has the right mix of ingredients, it'll stay hot even in the winter.

I never manage to keep my compost hot in the winter. I think it's mostly because my bin is too small (only 11 cu ft), but I also don't turn it very often in the winter.

during freezing weather, my compost pile prefers a double cappuccino, extra dry......