Last month was uncharacteristically dry and warm in Tucson; the official rain gauge at the airport recorded only 0.03" of rain in November. In an "average" year, we'd get 0.57".
Highs have been at least ten degrees above average since mid-November.
November set several records, including one for the warmest Thanksgiving weekend ever; the average temperature for the four-day weekend was 67.1°. It was also the third warmest November on record. And, unless we see a drastic cold snap this month, 2012 may down as one of the warmest years ever.
According to J.J. Brost, a forecaster with the National Weather Service's Tucson bureau, the mild weather is being caused by an unusually large dome of high pressure that's parked on top of us. Until it moves, it's shunting the cold air and rain to our north.
Mild weather will continue for the next week, with a hint of a change after that. Brost says some computer forecasting models predict a low pressure system arriving here next week, which would bring cool, cloudy and possibly rainy conditions. But Brost cautions that some of the other models have the system missing us entirely.
Read the National Weather Service's November and Fall 2012 Climate Report for Tucson.