Fall in Arizona: Autumn brings big changes to Valley weather

PHOENIX - Fall is one of the most beautiful times to be in the Valley of the Sun.

After our scorching summer highs at 110 or above, with lows in the 80s and sometimes even 90s, relief finally arrives.

Some years, it takes a bit longer for the cooler air to move in, but on average we only see one triple digit day in October.

The month begins with an average high of 94 degrees and ends with an average high of 83. Lows start out in the low 70s and typically fall to the upper 50s by Halloween.

November brings an even bigger cool down before temperatures even out through December. Our average high temperature in Phoenix drops from 82 degrees Nov. 1 to only 69 degrees by Nov. 30, with lows dropping from the upper 50s to the upper 40s.

Typically, the jet stream starts to shift farther south as we head into fall, bringing Pacific storms through the Great Basin. Those storms, passing to our north, work to dry us out and cool us off.

Usually by November and December, the jet stream is far enough south to bring Pacific storms right through Arizona dumping rain in the Valley and snow in the high country.

Often times, we can look to the presence of El Nino or La Nina to give us a good indicator of how the weather will play out in the Fall and Winter.

With neutral conditions now that are expected to last through at least early next year, there are no clear indicators as to how wet or dry we will be.

Long term, it looks like our average temperatures will stay above normal through with equal chances of above normal or below normal precipitation around our state.

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