Answer: You didn't give us too many clues to go on, so we can only give general information. During the summer months cool season grasses can dry out, but they green up again when the weather cools. So, if you live in an area with cool winters and hot summers, this may be why your grass is dry. Grasses usually do well with about one inch of water per week. If you're not watering once or twice a week during the summer months, that might be why the grass is dry.
A build up of thatch, or compacted soils can also make your grass look dry, even if you're watering regularly. If this is the case, fall is a great time to renovate your lawn. Rent a dethatcher or aerator from your local garden center. When the job is finished, reseed the entire lawn and keep it watered. It should perk up in just a few weeks.
Best wishes with your lawn.
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