Mammoth Mountain Weather & Discussion
Almost Daily Weather for Mammoth Mountain and the Southern Eastern Sierra
Monday, September 7th, 2026 @ 10:46 AM
Weekend Weather Summary: The trough that was off the Pacific Northwest coast last week has now progressed right over Oregon this morning. The low will quickly lift NW and be over Montana by Tuesday afternoon.
In the lows place, a cutoff low will be forming well off the California coast. To our SW, the 4 corners high will be making its presence known again. Models bring the 594 DM line over the Eastern Sierra this week, bringing back a taste of late Summer weather.
The warm and dry pattern will bring with it more fire danger to the area.
By the weekend, the high will be weakening in our area as the next low-pressure system drops in as a northern inside slider. That pattern will drop temps by next Sunday by about 6-9 degrees in all areas of the Eastern Sierra.
3 Day Forecast:
Main Lodge / Mammoth Lakes Basin: Sunny, with a high near 65. Southwest wind around 10 mph, with gusts as high as 30 mph. By Wednesday, mostly sunny, with a high near 73. Winds southwest around 5 mph.
Mammoth Lakes: Sunny, with a high near 67. Southwest wind 5 to 15 mph, with gusts as high as 40 mph.
Fire Permits and Restrictions: Stage 1 Fire Restrictions are in place. To learn more about the USFS Fire Restrictions, visit this link.
North East Pacific Infrared Satellite Image
Intelicast Radar
Mammoth Weather Discussion & Fantasy Long-Range Outlook
9-7-2026 @ 11:30 AM – The 4-corner ridge fooled me and will build back stronger than expected for a few days this week; then, as mentioned above, the next low comes in a northerly inside slider. All along, you can see the cutoff low well off the coast in the gif below.
Beyond week one, the model slowly drifts the low a bit closer to California, with the ridge just keeping the area a bit above average as far as temps go.
That far-out confidence is low in the exact location of the 4 corners high and the low off the coast. Where they end up will determine how warm or cool the area is during that time frame. As of now, I don’t see any of the tropical systems moving up into or part of California anytime soon.
I will update this Mammoth Weather page again on Wednesday by 5 PM.
Until then, have a great day, Snowman out:)
Weather Videos
❓ Top Mammoth Weather Questions (from the Snowman)
When does Mammoth usually get its first snowfall?
Light snow can fall in late September, but consistent snowfall usually begins in late October or early November. Opening Day typically lands between November 10 and Thanksgiving, depending on storm activity and snowmaking.
How does the ENSO pattern affect Mammoth’s late fall and winter weather?
ENSO (El Niño/La Niña) plays a big role in Sierra storm patterns. El Niño winters often bring warmer, wetter storms. La Niña typically favors colder, backloaded seasons with more snow from February through April. Neutral years are the wildcards with high variability.
What is 500mb height and why does it matter?
500mb height maps show atmospheric pressure around 18,000 feet — a critical layer for tracking storm tracks, ridging, and jet stream placement. Watching 500mb patterns helps forecast Mammoth’s incoming storms and long-range trends.
What are the PNA and PDO, and how do they affect Mammoth weather?
The PNA (Pacific-North American Pattern) influences western U.S. ridging and troughing. A negative PNA favors cold, stormy setups. The PDO (Pacific Decadal Oscillation) affects sea surface temperatures in the North Pacific — a negative PDO often aligns with enhanced storm delivery into California during winter.
👉 Want more answers? Check out the full Mammoth Weather FAQ – 50 Expert Answers to learn more about storms, snow, winds, and long-range patterns from a trusted local source.
Author Bio: Steve Taylor, The Mammoth Snowman. Over the last 40+ years, Steve has spent countless hours studying and learning about Mammoth Mountain Weather and Snow Conditions.
Dr. George, Don Marcelin, Howard Sheckter, and Ted Schlaepfer were his weather mentors at that time. Steve used to hang out with Howard in the Weather War room in the early ’90s, getting first-hand knowledge of Mammoth Weather from the (The Dweeb) himself.
Steve has spent countless hours reading, studying, and watching weather discussions from the NWS and multiple Private Weather Forecasters. He is a long-time member of WeatherBell, Weather West, and AccuWeather Pro. Disclaimer: Steve is a hobbyist forecaster with over 35 years of experience reporting recreational weather and travel reports for the Mammoth Lakes area.