Visit the Oklahoma Mesonet to see what the soil temps are in your area. Once the temps are consistently at 50 and above it's time to plant
wealth of information here. I have their app on my phone and is super easy to use.....but here is a computer link to the same info if you have never been there
https://www.mesonet.org/weather
I use it daily.....seeing temps, rainfall, wind direction showing position of approaching fronts, etc