Yep, 75 is pretty good for Jack Herer. It also prefers it a little on the dry side, so try to keep RH to 40‐50%. Honestly, JH is pretty resilient, you can beat up on them and they won't even flinch.
A standard, well ventilated grow space should be kept between 75-85 degrees Fahrenheit under optimal conditions. Temperature can be raised or lowered according to your plants' needs.
70-80 is a good temp. I keep mine around 70. Sometimes it creeps up toward 80 during the day. I would pay more attention to humidity and keeping it below 50% with good air circulation.