much has to do with the strain...for example an african strain will probably be 'perfect' at a higher temperature...i would probably say the 'right' temp could go up to around 88 at its top, depending on the strain, and as low as 68 or or 70 for strains originating in europe etc...i think we can all agree that for the most part, stay in the 70s and ur good...also i read that in the "dark" hours of the light cycle, if possible, dropping the temperature slightly is good, but don't drop it more than 10 degrees...so if you have ur shit at like 76 and can get it to drop to 71 while its sleeping, you are in the range on both, and the plant will like that cuz its more 'natural'