1995 Lexus E300 Air Conditioning

It may be low on freon, the pressures are low in the morning and rise as temps do.

Use on of those quick freon kits that come with the fill tube and gauge. It sounds like you have a slow leak and on a hot day there is enough pressure in the system to trip the switch. If thats not the problem check the wiring coming from the switch. The switch is probably near the filter/dryer. Thats the metal canister that sweats liquid on a hot day.