I am wondering if anyone knows of an Android app that can alert me whenever the weather is expected to go below a specified temperature overnight?

This is my first year planting sweet potatoes, and the weather report showed the next 10 days all had lows over 50 degrees, so I thought it was time to plant outdoors here in Fort Worth. However, now the weather report shows multiple days under 50, so I may have jumped the gun a little and need to cover them on cooler nights...