- October may have a divided personality across the United States
- The month is sure to start out very warm for most, except in the West.
- However, this pattern is expected to reverse, based in part on the last strong El Niño in October.
October may start out feeling like a summer month in most parts of the United States, but that pattern could change, according to updated forecasts from The Weather Company, IBM Business, and Atmopheric G2.
What are the changes in the latest October forecast? Updated temperature forecasts warmed noticeably in the center and northeast.
Temperatures will be above average throughout the Plains and upper Midwest. Warmer-than-average conditions will extend into much of the Northeast, as well as into the Rocky Mountains.
The only areas that could deviate slightly cooler than average are the Florida peninsula and parts of northern California and Nevada.
What drives this view? The month will start with a pronounced “omega block” weather pattern that will pump warmth across much of the central and eastern United States, while the Great Basin and West Coast will be relatively cool.
But that pattern could change, and it could happen as soon as the first full weekend of October, a computer model guides. This change could cause temperatures to fall closer to average in the central, eastern, and southern United States, while causing the West to warm.
That's the big question with this look. When will this change in pattern occur and how long will it last during the month?
There is also a connection to the El Niño phenomenon. According to Todd Crawford, director of meteorology at Atmospheric G2, October during El Niño tends to be cooler than average in most parts of the country, except for the West Coast and South Florida.
These are two big cards in this view that could lead to a much different outcome.
What is the average for October? High temperatures continue their downward trajectory during the main month of fall. Average highs over the entire month across the northern tier are generally in the 50s and 60s.
Farther south, the highlands are still very warm, with temperatures in the 70s and 80s being more common.
Mornings also get colder quickly. Lows drop into the 30s and 40s across much of the northern United States from the Northwest to the Midwest and Northeast.
Lows in the 50s and 60s are common across much of the South and Southwest. Mild mornings continue in Florida, with morning temperatures in the 60s and 70s typical in October.
The Weather Company's primary journalistic mission is to report on breaking weather news, the environment, and the importance of science in our lives. This story does not necessarily represent the position of our parent company, IBM.