Mammoth Mountain Weather
Forecast & Discussion
Mammoth Mountain Weather Discussion
11-14-2025 – Good morning, folks. It’s 11 AM, and all the new weather data is in. We’re dealing with a deep low-pressure system parked off the central California coast. Instead of swinging inland, the low is drifting south, and that track has warmed the storm and limited snowfall so far.
As the low continues dropping south, it’s going to stall for a bit before the next upstream system nudges it inland to the northeast. During that stall, the circulation will pull a big surge of moisture back into the region on Saturday. Snow levels remain high throughout the day, around 9,000 to 9,500 feet.
By Saturday evening, snow levels begin to drop toward the Main Lodge. On Sunday, they fall to about 6,500 to 7,000 feet as the colder core of the system moves closer to Mammoth Mountain.
By Monday morning, the low sets up just off the central California coastline, and that could drag snow levels down to around 5,000 feet.
The exact track of that second low is the key to how much cold air and moisture we can squeeze out. The ECMWF ENS, which has been the most reliable this season, shows the low moving south like the GEFS but hugging the coast a bit more, and that is a far better path for Mammoth.
As of this Friday morning, if we lean on the ECMWF ENS, the NBM, and the GEFS together, there’s potential for another 1 to 2 feet of snowfall by Tuesday. Confidence is on the low side since last week’s system shifted about 48 hours before arrival, so we stay flexible with expectations.
Here is the following week on the ECMWF ENS
What About Snowmaking?
Friday stays out of reach. Saturday night is marginal up high. Sunday night through early Tuesday is the first solid window for Mammoth to build snow in the McCoy and Main Lodge zones.
NOAA 6-10 Day & 8-14 Day Outlooks
❓ 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.