for me low 30's is a normal summer day, hell, even in spring and autumn here in tropical Queensland that temp is common!
for example, last night the room temp was 27 and after the PC was on for a while, it reached 39 (southbridge).
I have a wall mounted, wooden, open to the air, custom built rig I did a four years ago.
I added two digital thermometers - one for the ambient temp and one on the SouthBridge as it's not actively cooled by anything and gets rather hot.
whatever cooling system you use, it should keep the processor within, say 20-30C of the ambient temp. any more than that and you are either over-working the system like playing games or you have an airflow problem.
have you changed the thermal paste on the processor?
try leaving the side cover off and blowing a fan into the chassis.
doing nothing and hitting 88 is concerning - have you opened it up and checked the CPU fan is indeed working?