I draw my water and let it sit while using air stones before I water with it as it is too cool, especially in the Winter. I also feed my plants with tea so I've seen the differences in pH as the water sits. So I draw the water and a day or two before I need to feed I add the nutrients. A day or two later I will adjust the pH before I feed the plants.
Temperature does change the pH reading for electronic pH meters but they have compensation for that. Even at that, the worse case scenario would be .5 difference at 4.0 pH with a moderate temperature difference. At 7.0 the difference would be about .02, very little.