During the summer, there are massive heatwaves, and the temperatures are also very high. These factors can cause your grass to become scorched, which does not mean that your grass is burned.
It is still alive since the heat has not damaged the roots, but the grass might appear yellow. One of the best countermeasures for this heat in the summer is watering your grass to counter the heat.
Run the sprinklers long enough to get the soil around the deepest roots wet.