Quick answer
Keep mowing as long as Bermuda is growing. Once it stops after the first frosts, typically in late fall in central Oklahoma, you can make a final mow and put the mower away.
Signs It's Time
- Grass hasn't grown noticeably in a week or two
- First frosts have turned it tan
- Leaves are the main thing on the lawn
Final Mow Height
Keep a normal height on the last mow. Scalping right before winter can expose the grass to cold.
Fescue Lawns
Fescue keeps growing in cool weather, so shady fescue areas may need occasional mowing into winter.