If you have a spare bath tub, I usually fill it part way up and let the buckets sit in that for their fermentation, and clearing stages. Water takes longer to heat up, so when the temps go up in the day you only see a few degree variation. The same holds true for when it cools down at night. The water loses heat slower, and therefore keeps a decent temp range. If you don't have a spare tub, you can always try something big enough to hold your bucket and some water.
That's what she said.