Id say 28c is max optimal in veg lol you really dont want to be growing them in 38c temps unless you absolutely have too the 70% humidity isnt the end of the world you just have to make sure you have fans blowing on and under the canopy and dont let bud sites touch or to many leaves cluster up Thats not to say she wont grow in 98 degree weather lol my first grow I veg'd 80% if the time in triple digits and they did just fine once I took care of the nute problem... however it depends on the strain and health wise its recommend to be around 70-80 imo.