With temps in the 90's and high humidity the past few days we have developed some hot spots in our greens. They are purple in color which is a sign from the turf that it is stressed. During periods of high humidity we have to be careful with our irrigation practices to not overwater. If we do the roots may literally cook in the hot rootzone. While a bit unsightly the turf is not dead, just off-color and will recover quickly. In a week it will not be noticeable.
Here's a good article on heat stress in turf for review:
University of Tennessee Heat Stress Article