2002 GMC Envoy XL SLT A/C issue

OK…I am baffled. I live in Houston. 95+ degrees everyday. I work nights. Get in Envoy when it’s 88 degrees outside at 930pm. A/C usually works. Leave work at 0800 when it’s 86 degrees outside. A/C usually works. When it’s 95+ degrees at 1230pm in middle of day, A/C does NOT work. Any ideas??? PLEASE!!!

Define “NOT work”.

Compressor does not kick in to supply cold air. The fan still blows at desired speeds and through desired vents. And, compressor initially kicks in when engine revs above 3500rpm or so. Will not kick-in at idle.

Do you have any ideas? Compressor does not engage when temperatures ouside reach over 92degrees. Any cooler, it will engage but I have to rev the engine near 3500rpm. The cooler it is outside, the lower it will engage on the rpm gauge.

Move to Buffalo.

Not an option