Cutting it less frequently when it's stressed due to heat is a good
idea. Plus, it should be growing slower with high heat and less water
anyway. Sometimes I see commercial mowers running over brown lawns
when there is nothing to cut. All they are doing is damaging it.

For watering, ideally it should be watered deeply, which means 3/4 to
1 inch of water. You need to figure out how that translates into time
based on your sprinkler system. Empty tuna cans can be used to
measure. How often depends on weather conditions and what kind of
soil you have. With real good soil and moderate temps, you can go
about a week. With poor soil and high temps, you may need to water
every 3 to 4 days. You can also see when a lawn needs water by looking
at it. The grass starts to change to an off color, like slightly
bluish and when walked on, no longer springs back.

I would time the watering so it ends by about 8am. That way you
minimize the overnight wetness, but still can get the water down when
evaporation is low.
The worst practice is to water shallow and every day. This encourages
shallow roots so that the lawn needs even more water and also can lead
to fungus and disease problems.