Mammoth Mountain Weather & Discussion
Almost Daily Weather for Mammoth Mountain and the Southern Eastern Sierra
Thursday, July 9th, 2026 @ 9 AM
Weather Summary: A strong ridge of high pressure is just off the Southern California coastline. This pattern will produce warm days with clear skies, along with a moderate SW wind at 10-30 MPH at times through Saturday.
The ridge progresses off toward the 4 corners region by Sunday, bringing on a bit of a cooling trend as heights will lower. By early next week,k the position of the high looks to bring in the first surge of the Summer Monsoon season with T-Storms and Showers early next week.
Detailed Local Weather Forecasts
Main Lodge / Mammoth Lakes Basin:
Friday & Saturday Sunny, with highs in the upper 70s. Southwest wind 5 to 10 mph, with gusts as high as 30-35 mph.
Sunday, Partly sunny, with a high near 86, with light winds.
Monday: A chance of showers and thunderstorms after 11 am. Partly sunny, with a high near 82.
Mammoth Lakes:
Friday & Saturday Sunny, with a high near 84-88 degrees. Southwest wind 5 to 15 mph, with gusts as high as 30-35 mph.
Sunday, Partly sunny, with a high near 82.
Monday – A slight chance of showers, then a chance of showers and thunderstorms after 11 am. Partly sunny, with a high near 77.
Bishop:
Friday, Sunny, with a high near 102. Calm wind becoming southwest 5 to 8 mph in the afternoon.
Saturday, Sunny, with a high near 103. Light and variable wind becoming south southeast 11 to 16 mph in the afternoon. Winds could gust as high as 28 mph.
Sunday, Sunny, with a high near 98. There is a 10-20% chance of showers and T Storms.
The longer range:
Next week, look for the 4 corners high to be in the right positions to kick off the first summer monsoon flow into the area.
Look for showers and thunderstorm possibilities across the Eastern Sierra and the Owens Valley on Monday and Tuesday. Beyond that time frame, the 4 corners high looks to be in place, bringing daily build-ups and at least an isolated chance for t storms.
The EU is outputting T Storms and QPF daily from the 12th out at least 10 days. Nothing major, but hopefully wet storms, not dry ones with fire starts.
Temperature-wise, I see the Eastern Sierra locked into the 591 DM line most of the time with a couple of surges that could result in very hot temps for a day, 8 to 10 days out.
The EU AI model is cooler than the main ensemble is so hopefully it’s on to something.
I hope you’re having a great Summer, Snowman out…
Here is the ECM Ensemble Model out to day 16. The 591 DM is within the Eastern Sierra during most of this time frame. That keeps mid-day temperatures in Mammoth Lakes in the lower 80s, with Crowley / Toms Place in the upper 80s. With Bishop in the upper 90s to lower 100s.
The good old days of Summer, it could be much worse heat-wise.
Have a great day, Snowman out…
Here is the QPF output from the ECMWF.
Daily Afternoon Summer Zypher winds will continue for the foreseeable future.
Temperature Anomalies GiF
❓ 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.