Building boost and Atmospheric conditions

[Onefast99gsx]

Does the outside air temp and whether it's humid out have a direct impact on the amount of boost you build? The reason i ask is because the other day my MBC was set about about 22psi. The following day i cranked it over a 1/2 turn and tested the car and i wasn't building any more boost. Sunday was much hotter than Sat.

Thanks!