Welcome to the weird world of CA daily temperatures. August usually has a few high temperature days and is warm, but September is usually warmer with steadier daily heat and when one thinks it should cool down - it doesn't. The mean daily temperature for September is higher than August in most parts of southern California. October cools down a bit - but is much like June or July and then suddenly a cold wave will come in with the shorter days and the temps will drop - usually right about now.

This sort of weather is par for southern California and October brings the first Santa Ana winds, usually caused by the disparity of temperature between the now cooler oceans and the still hot land masses. As the weather cools down, the winds get heavier and then in December and January when it actually starts to get "cold" in SoCal, the Santa Ana winds stop. Sometimes the winds are warm, other times they are cold but they are closely linked with Autumn and are usually a welcome sign as they signal the final lowering of temperature.

Arizona is different. August is the hottest month and September is just slightly cooler. October is a lot cooler but still with a few hot days.

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