There is just one region in United States of America in September experiencing the rainy season and this is Florida - Peninsula east. According to September weather statistics, 7 of 24 regions of United States of America have the dry season. These regions are Oregon, Washington, California - West coast, California - South coast, California - Mountains, Wyoming - National parks, Nevada. 22 of 24 regions have the tourist season in United States of America in September. These regions are Great Smoky Mountains, Texas - Coast, Florida - Northwest coast, Florida - Peninsula west, Florida - Peninsula east, South Carolina, North Carolina, Oregon, Washington, California - West coast, California - South coast, California - Mountains, Montana - National parks, Wyoming - National parks, Nevada, Utah - National parks, Arizona - National parks, Delaware, New York, Rhode Island, Michigan, Hawaii.

The lowest value of the day temperature in September in United States of America can be seen in Alaska with a value of 12.4 °C (54.4 °F). The highest day temperature in United States of America in September can be found in Nevada, where the value of day temperature is 34.6 °C (94.3 °F).

The lowest night temperature in United States of America in September can be found in Wyoming - National parks, where the value of night temperature is 0.2 °C (32.3 °F). The night temperature in United States of America in September is the highest in Florida - Peninsula east - its value is 23.7 °C (74.6 °F).

The lowest sea temperature in United States of America in September can be found in Oregon, where the value of sea temperature is 13.8 °C (56.8 °F). The highest value of the sea temperature in United States of America in September can be seen in Florida - Peninsula west with a value of 29.1 °C (84.5 °F).

The lowest value of the number of rainy days in United States of America in September can be seen in California - South coast with a value of 1 days. The highest number of rainy days in United States of America in September can be found in Alaska, where the value of number of rainy days is 16 days.

The lowest rainfall amount in September in United States of America can be found in California - South coast, where the value of rainfall amount is 5 mm (0.18 in). The rainfall amount in United States of America in September is the highest in Florida - Peninsula east - its value is 196 mm (7.73 in).

The wind speed in September in United States of America is the lowest in Great Smoky Mountains - its value is 2.2. The wind speed in September in United States of America is the highest in Hawaii - its value is 5.0.

The humidity in September in United States of America is the lowest in Nevada - its value is 28 %. In United States of America in September - the region with the highest humidity is Alaska. The value in this region is 80 %.

In United States of America in September - the region with the lowest number of sun hours (without clouds) is Alaska. The value in this region is 5 hours. The highest value of the number of sun hours (without clouds) in September in United States of America can be seen in Nevada with a value of 11 hours.

The lowest value of the clear sky percentage in September in United States of America can be seen in Alaska with a value of 39 %. In September in United States of America - the region with the highest clear sky percentage is Nevada. The value in this region is 90 %.

The lowest day length in United States of America in September can be found in Hawaii, where the value of day length is 12 hours. In September in United States of America - the region with the highest day length is Alaska. The value in this region is 13 hours.