I can't find anything in the product information about this, but in practice, it appears to me that the tolerance for this thing is fairly high. It doesn't seem to come on until the temp is about 2F below what its set at. It does seem to shut off on schedule.

I had it set to 80F and noticed this morning that the soil temp was down to 78.4F and it hadn't come on. I removed the humidity dome which is always followed by a drop in soil temp and a little later it had come on, so I'm not sure how low it had to drop before it powered up, but it was less than 78.4F.

For now I've turned it up to 81F in the hopes that it'll come on at least by the time its dropped to 79F (or so).

Does anybody have the specs on tolerance for this? I'm wishing I'd bought a herp thermostat now.