September month is the last month that end with starting of the autumn season in the USA in most regions. This change in temperature affects the lawn grasses(according to their recent growth) whether it is cold climate grass or hot climate lawns. Here, you will get a guide to taking care of your lawn in September(distinguished for cold and hot climate grasses). September lawn grass care, maintenance, and treatment in the USA Weather conditions in September(USA) In August, the overall temperature of hot regions starts to low down from hot to moderate in the average hotter regions of the USA. Following is the average weather of the hot and cold regions of the USA in September- September weather in hot regions Following is the week-by-week weather change and the average range in hot regions of the USA- 1st week - Moderate(25 to 28 degrees Celsius) 2nd week - Moderate(22 to 25 degrees Celsius) 3rd week - Moderate to low(22 to 24 degrees Celsius) 4th week - Moderate to low(20 to 22 degrees