California, Nevada, and the Western U.S. Expected to See Above-Average Warmth as the Midwest and Eastern States Turn Colder Over the Next 10 Days

UNITED STATES — A Significant West–East Temperature Divide Is Setting Up Over the Next 10 Days, A noticeable shift in the national temperature pattern is taking shape, with warmer-than-normal conditions expanding across California, Nevada, Utah, Arizona, and much of the western United States, while colder-than-normal weather spreads through the Midwest, Great Lakes, and Eastern states.

This pattern is expected to last through the upcoming 10-day period and may bring several reinforcing surges of colder air into the eastern half of the country.

The imagery shows a strong color contrast across the country — darker reds in the West for warmth and deeper blues in the East for colder conditions — illustrating how sharply divided the temperature outlook has become.

Warmth Expands Across California, Nevada, Utah, and Much of the Western Region

The western portion of the country is positioned for a stretch of above-average temperatures. Key areas include:

California, where highs may run well above seasonal norms
Nevada, Utah, and Arizona, seeing similarly warm conditions
Portions of Oregon, Idaho, and Montana, also trending warmer

This setup favors clearer skies, reduced storm activity, and milder afternoons. Some areas, especially California and the Southwest, may see continued dryness during this period.

Colder-Than-Normal Weather Targets the Midwest, Great Lakes, and Eastern U.S.

While the West warms, a broad pocket of colder air is expected to stretch across:

Illinois, Indiana, Ohio, Michigan, and Wisconsin
Pennsylvania and New York
Kentucky, West Virginia, and surrounding Appalachian states
Parts of the Mid-Atlantic and Northeast

Temperatures in this region are expected to run noticeably below seasonal averages, especially during the coldest stretches of the next 10 days.

Potential Effects of the Colder Pattern

Increased heating demand
Sharply colder morning and nighttime temperatures
Occasional icy or slick road conditions
Periods of lake-effect snow downwind of the Great Lakes
Wind chills dropping to uncomfortable or hazardous levels during stronger cold spells

This setup also allows quick-moving disturbances to form, producing bursts of wintry weather across several states.

What Is Causing the Temperature Split?

The country is currently experiencing a ridge in the western states and a trough across the central and eastern states.
This alignment supports:

Warm, stable air dominating the West
A steady path for colder northern air to move south through the central and eastern regions

This type of configuration can remain locked in place for days, leading to prolonged warmth in the West and repeated cold shots in the East.

Arctic Air Surges Possible in the East

Within the colder zone, a few stronger pushes of Arctic air may develop. These colder bursts can bring:

Sudden temperature drops
Hazardous wind chills in the Midwest and Great Lakes
Increased chances for snow in parts of the Northeast
Blustery conditions following frontal passages

Residents across the central and eastern U.S. should plan for fluctuating temperatures and occasional sharp cold snaps.

Looking Ahead

If the current pattern holds:

The West will stay warmer and generally quieter
The Midwest and East will remain the coldest regions of the country
Temperature swings will be most noticeable between December 14–19
Additional cold surges could develop closer to late December

Updates will continue as new data becomes available.

Stay connected with ChicagoMusicGuide.com for evolving weather updates and region-by-region coverage throughout the season.