When the temp goes up along with the humidity, do my trees require more water?
Higher temperature and higher humidity would cancel each other out in terms of water use. So it depends on how much each increases as to whether water use would increase and how much. At this time of year my trees seem pretty well adapted to the water deficit that I try to maintain all summer. So I can forget to water on schedule and they seem to shrug it off.
If your temperature and humidity have both increased I'd stick with what's been working all summer.
Mn has been hot and humid with temps averaging 15 degrees over average. I have noticed that my grapes with the clay soil does a lot better than the ones with black soil so I don't water them as often as the black soil. Clay hold the water a lot better than most soils. I have a pear and apple tree and they have been alright and when I do water I trickle them and the grapes and its the best way to water your trees and plants. You should check the leaves and they will tell you how they are doing and you can find info on the garden forum about the leaves.
Good luck Dave