We have been getting a lot of questions about warm season grasses like bermuda and zoysia, being dead or not greening up in Alpharetta, Georgia.
Warm season grasses come out of dormancy or "green up" when soil temperatures constantly stay above 65 degrees at a 4 inch depth. The soil temperatures at the Golf Club of Georgia in Alpharetta, over the last 15 days have ranged from 56 - 61 degrees at a 4 inch depth. So, with having cooler nights, over cast days, and a few frosts over the last 15 days things have slowed down. Once we get to mid-May/June everything should be greened up and growing and you'll be mowing like crazy.
I have attached some links to the UGA Soil Temp site and a document on Bermuda Grass for reference.