Yard turns yellow in spots when it warms up
I live in Seattle, WA. I have a beautiful green yard until around the beginning or middle of July when it warms up. then my yard starts turning yellow in spots. this is the 4th year in a row. warm here is 80-90 degrees. I thought I figured out what fungus it might be, so last year I put Ortho Max lawn and garden insect killer on the yard, as it called for, it ended up getting 4 applications. I thought I would be past the dead yard, but it's back. I water 20 minutes every morning, and fertilize every 2 months
Many grasses go dormant in summer and get a little yellow. The only way to keep grass green in summer is to water a lot. The way to get through it is to set the mower blade higher and water as much as you can and keep traffic to a minimum. Most grasses will recover in the fall after the grass is aerated, dethatched, top dressed and fertilized. As for the brown spots on the lawn, depending on the kind of grass you have it may be army or sod web worms which can mimic drought stress.
I have a problem like this in my yard, turns yellow in the same spots when it gets hot even thou I run sprinklers 3 times a week. I took a big long screwdriver and tried to push it into the ground in these spots and it was so hard I could barley push it them 3 inches deep. I cut my grass in these spots and rolled it back to expose the bare ground, what I found was something that looked like concrete. I took a hammer and busted it up so I could get it up and filled in the hole with composted cow manure. I can't tell where the spots were now, it is as green as the rest. I still have one spot that I haven't dug up yet because it is so big and it is quite a job to dig it out.