I can’t say definitively what the issue is with your grass from photos but below is some good information with picks to help you nail it down. 

Our wet spring has caused a lot of problems because lawns have not had a chance to dry out well between rainstorms. 

If you have a sprinkler system make sure that you are not overwatering. Set it to go on early - 4:00 am is a good time. Also make sure you let your lawn dry out between waterings. 

https://apps.extension.umn.edu/garden/diagnose/plant/turf/discolored.html

https://extension.umn.edu/lawns-and-landscapes/lawn-care#watering-your-lawn-1759561