Ok, I'd like some opinions to put my worries to rest. I built my own incubator and have had two hatches so far with some fairly wide swings in temp and humidity. Still got at least 3 to hatch out of a dozen each time. Last Sat I set another batch but this time I tweeked the bator and perfected it to hold a steady 99.5 to 99.9 with 50% humidity constantly, I was so proud, then of course disaster strikes on the fourth day. My AC unit quits working on the second floor of my house and that's where the incubator is. I was up all night making adjustments and trying my best to keep the temp within tolerance. It swung from 99.1 to 101.9 but only for short periods of time. The AC was fixed by late afternoon but then because of my adjustments I was fighting too low temps of 97.9 to 99.7 again for only short periods ( no more than an hour). I've heard that temp variations are a bad thing but does anyone know if it will really seriously affect the hatch over a 12 hour period if it still stayed within the safe zone somewhat? P.S. everything is stabilized now holding steady at 99.5 to 99.9 again.