Summer did not wind down quickly this year as temperatures were much warmer than average across most of the Western U.S. in September and wildfires continue to burn heading into early October. Mild conditions are likely to continue through much of October with above-average temperatures expected throughout the West. 

September 2024 Review

Temperatures were well above normal for most of the West, and some areas in Eastern Wyoming even saw their warmest September on record.

The first 10 days of September featured summer-like temperatures with a period of cooler weather in mid-September. Toward the end of the month, temperatures rebounded to unseasonably warm levels with some areas breaking high temperature records.

The Southwest, Pacific Northwest, and portions of the Central Rockies were drier than normal in September. Parts of the Northern Rockies, Great Basin, Sierra, and Southern/Central Colorado received near to above-normal precipitation. 

The West saw most of its precipitation during the middle 10 days of September with some areas receiving impressive rainfall totals during this time. Many mountain areas also received their first snow accumulations of the season.

However, late September proved to be very dry for much of the West, and wildfire activity has picked up recently across the Northwest and Northern Rockies as a result. 

Whether or not you are enjoying the warm and dry weather likely depends on your location, elevation, and whether or not there are wildfires burning nearby.

In many high mountain areas, the mild weather lately has resulted in excellent hiking and biking conditions as temperatures (while warmer than normal) have still been cooler compared to peak summer heat in July and August.

Also, fall colors have been outstanding across the Rockies over the past 10 days. As of October 2nd, most areas in the Rockies are right around peak or just past peak color. Areas outside of the Rockies can expect to see their best color over the coming weeks.

View → Fall Colors Map

October 2024 Outlook

It looks like we are going to hang onto the mild fall weather for a bit longer as there is high confidence for above-normal temperatures throughout the West in October – especially in the Central Rockies and Southwest.

Keep in mind that "average" temperatures quickly decrease during October as the days get shorter, so nights/mornings will still be cold in high mountain valleys during this pattern. Also, the threat of colder weather will increase later in the month, even with the overall warmer outlook. 

Below-normal precipitation is also expected across most of the West during October. However, the Northwest and Far Northern Rockies have equal chances of above or below-normal precipitation as the average position of the jet stream should eventually shift southward from Canada into the Northern U.S. over time. 

Fire and Smoke Outlook

Usually, fire season is winding down across the Northwest and Northern Rockies by this point in the year. But that is not the case this year as wildfires are still burning actively across Idaho and Western Wyoming as of October 2, and fire danger will remain elevated for as long as the warm and dry pattern continues.

Autumn also coincides with peak fire season in the downslope wind regions of California (Santa Ana winds, for instance), and above-normal fire potential is expected in these areas during October.

Thanks so much for reading! I will post the next monthly update in early November.

Alan Smith