The weather in Mckinney in September is hot. The average temperatures are between 19°C and 30°C. Usually the days in September are hot while the nights are a bit cooler.
You can expect about 3 to 8 days of rain in Mckinney during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Mckinney in September 2025.
If you’re planning to visit Mckinney in the near future, we highly recommend that you review the 14 day weather forecast for Mckinney before you arrive.
Temperatures
30° / 19°
Rainy Days
5
Snowy Days
0
Dry Days
25
Rainfall
101
mm
Sun Hours
10.7
Hrs
