With the hot-dry weather, it's been a struggle to keep the lawn watered and green. I know green grass is nicer to look at than brown-but are there any inherent problems with laying off on watering and letting the grass go dormant-at least during the hottest months?

It seems like this could reduce the frequency of weeds too?

Thanks! 

I'll disagree with Mr. Green.  Dormancy can actually benefit the turfgrass because it allows it to shut down during the difficult hot summer.  Drying of the roots has also shown to encourage the plants to increase root mass to seek out water.  Contray to the other post a dormant lawn doesn't see much weed encroachment either.  If weeds aren't present when the grass enters dormancy it is difficult for them to germinate with no water.  The only places I am seeing weeds in my dormant lawn now are at the ends of the downspouts because that soil had more moisture.  

Good Luck.  Remeber if it saves resources, brown can be beautiful.

Sparty 

First question that needs to be asked is What turf type do you have? Cool season lawns (Fescue, Rye, Bluegrass) are bunch type grass and do not have rhizomes (underground stems) like Warm season lawns (Bermuda, Zoysia, St Augustine) do. Many cool season grasses, if not given enough water to keep the crowns alive. will die and require re planting in the fall. Warm season grasses, like Bermudagrass, can safely go dormant and re grow from rhizomes. Since you describe dormancy in summer I assume you have a cool season lawn. If so, I would water the lawn at least 2-3 times a month to try to keep the crowns alive. You may find that one good deep watering once a week is cheaper than re seeding and watering even more for seed germination come fall.