Mammoth Mountain Weather Forecast & Discussion
“Daily zone-based weather updates for Mammoth Mountain, Mammoth Lakes, Crowley, and Bishop – plus Snowman’s forecast insights and ECMWF model discussions.”
Pray for Snow!
Tuesday, September 23, 2025, at 10 AM – It’s a gorgeous Fall day in the Eastern Sierra, with hazy skies and pleasant, cool temperatures.
Up Top, the temperature is 43 degrees with a NNE wind at 17 MPH, gusting to 25 MPH. Down at Main Lodge, there is an E wind of 2 MPH, gusting to 9 MPH, and the temperature is 58 degrees.
Current Live Windowcast View
Recreational Forecast for the next 3 Days – Expect clear skies through Wednesday and then a 30-40% chance of T Storms and showers on Wednesday and a 60% chance on Thursday. Rainfall amounts in areas of showers should be light, in the 0.20 to 0.30 range.
Temperatures at the Main Lodge and the Mammoth Lakes Basin are expected to remain in the low to mid-60s through Wednesday. On Thursday, mid temperatures will be in the mid to upper 50s. Nighttime lows will be in the mid-40s.
Winds: East to Northeast wind 5 to 10 mph, with gusts as high as 25 mph through Wednesday. Thursday, North wind at 5-10 MPH.
Mammoth Lakes will be in the upper 60s to lower 70s on Thursday, with mid-50s expected, and lows in the mid-40s. For Bishop, mid-to-upper 80s through Wednesday, with lower 80s on Thursday, and nighttime lows in the low to mid-50s. S to SE winds at 5-10 MPH during the afternoons.
With the smoke gone, now is the time to plan a Fall Adventure in the Eastern Sierra.
Recent Weather Posts
❓ 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.