Like everyone said, you're good up until 90....You really don't want to hit 80 unless you're running CO2, in which case you're at an optimum temp but it's not gonna fuck your shit up if you're not. What you really want to be concerned about is the temp difference when you're lights go off. If it's more than 10-13 degrees, you might run into PM issues....So if you're fluctuating between 80 and 85 during lights on and all of a sudden your temps drops into the 60's, then your humidity is gonna spike and in a matter of a week or 2, you'll start seeing PM