If I may, lettuce bolts due to long day length not heat alone.
People think it is heat because it gets hotter at about the same time as the days get longer.
You can actually stop it from bolting by covering it to stop the amount of sun exposure.
This also hold true for some plants that go to seed in the fall.
It isn't the cooler weather but the short day length and longer nights.
By interrupting the long darkness by turning on a light it will stop the plant from putting out seeds.
Three that I know of right off hand are cannabis, poinsettia and jade plants.
Worth