Mammoth Mountain Weather Forecast
Including Mammoth Lakes & Bishop, California
Friday, September 20th at 4 PM: Mammoth Mountain and the Southern Eastern Sierra have partly cloudy skies. The Ski Area picked up two dustings, one later on Wednesday and another late on Thursday.
Checking area weather stations this morning, up Top, the temperature is 41 degrees with an ESE wind at 19 MPH gusting to 30 MPH. At the Main Lodge / 8900 elevation level, the temperature is 55 degrees, with an SSE wind at 2 MPH, gusting to 8 MPH at times.
The temperature in Mammoth Lakes is 61 degrees. The temperature at the Mammoth Airport is 67 degrees, with 68 degrees in Crowley Lake and 83 degrees in Bishop.
Weather Forecast for Your Adventure
Weather Details for your Outdoor Adventure: Saturday into Monday for the Main Lodge / 8900 Feet. Midday temperatures at the 8900-foot level will be in the low to mid-60s. Overnight lows will be in the low 40s.
The wind will be SW at 5-10 MPH, with gusts up to 25-35+ MPH from Main Lodge up to the top of the Mountain.
Midday temperatures in Mammoth Lakes will be in the upper 60s to lower 70s, with overnight lows in the low to mid-40s.
For Bishop to Mill Pond, mid-day highs will be in the low to mid-80s, with overnight lows in the upper 40s to lower 50s.
Mammoth Mountain & Eastern Sierra Weather Discussion & Outlook
The low-pressure system that brought a dusting of snow to Mammoth Mountain on Thursday is heading south and into Southern California today. Cooler and drier weather will prevail into this evening, and then some warming will start on Saturday as higher heights move into the region.
The upcoming weekend should be fantastic for Fall Adventures, with warm seasonal temperatures in all areas and light winds.
For late Sunday into early next week, models predict a strong progressive high-pressure ridge moving into the Pacific Northwest and quickly moving east by midweek. That pattern will warm the region a bit more Monday into Wednesday.
Just behind the ridge, some weak troughing will set up off the west coast of California. That pattern will lower heights for a few days before higher heights and warming move into the area for the following weekend.
At this time, most of the models show no signs of precipitation over the next seven days. However, the ECM does have a few clouds and some very isolated showers the next few days.
The 8-14-day forecast period looks warm and dry as a new ridge of high pressure moves into the area, bringing more warm and dry weather.
Looking into the Fantasy Outlook period for October’s weather trends, the ensemble models still show warmer and dryer days. However, it does appear that around October 23rd and into early November, the weather could change over to colder, with some snow showers over the higher elevations.
Steve Taylor – the Mammoth Snowman
The next full Mammoth Weather Forecast Update will be Sunday by 5 PM.
Mammoth Weather Forecast Data from Weather Bell
ECM & GEFS Ensemble Models 500
10-Day ECM 500mb Anomaly GIF: Below is the entire 15-day run of the ECMWF ensemble model. I use this model to tell the Mammoth Weather Story you just read above. Compared to the other models, this solution has been effective more often than others over the years.
10-Day GEFS Ensemble 500mb Anomaly GIF: Below is the second most trusted ensemble model that we use that goes out to day 16. Model relaibily beyond day 7 can be very suspect expecialy during the transition seasons of Spring and Fall. 0
ECMWF Ensemble Jet Stream Gif
This is the Eastern Pacific View of the ECMWF ENSEMBLE Run of the Jet Stream.
Temperature Forecast
Upper-Air Temperature Anomaly GIF: The reds are moving over California, which means above-average temperatures are moving in once again.
*Temperature anomaly means a departure from a reference value or long-term average. A positive anomaly indicates that the observed temperature was warmer than the reference value, while a negative anomaly indicates that the observed temperature was cooler than the reference value.
The Wind Forecast
QPF Forecast
There is no QPF in the forecast over the next week to 10 days, except on the ECM, which has isolated showers this week.
Snowfall Forecast
Most models show the area getting no snowfall over the next ten days. The ECM does have some isolated dustings above 11,000 feet south of Mammoth Mountain around the 24th. Right now, I would buy into the dry outcome.
Precipitable Water Anomaly
45-Day Long Range Fantasy Outlook
This is the long-range ultra fantasy 45-day model run. These longer-range ensembles are suitable for examining long-range trends in the overall weather pattern. They should never be used or considered a forecast. We see below higher hights with drier weather in the region through most of October.
46-Day Fantasy Snowfall Outlook
These long-range snowfall outlooks are good for trends, and should never be considered a forecast. One thing I see in the long-range is a change to colder and snowier weather around 10/23 into the first week of November.
First Look at Snowfall Season 2024-25
9-5-2024 – When looking ahead to the next snowfall season, predicting what might happen is difficult at this time of year. If a weak La Nina does form (66%), there is a good chance we will have a drier-than-average snowfall season.
However, several very big winters have come from weak La Ninas over the last 25 years. (See the La Nina Winter chart down the page.) Everyone must also remember that many other factors are at play than just warm or cooler water along the Pacific equator.
For now, Ted (Powder Forecast) and I are not forecasting what the winter might be like. We will better understand how this may play out in late October / early November. As we have all seen in the past, patterns can quickly flip and change in late December and January.
La Nina seasons are like El Nino and can bring drought, moderate winters, or large ones. Many factors are at play, and the situation can change as the winter season starts to ramp up in mid-to-late December.
Let’s keep the positive vibes that Mammoth Mountain gets a perfect winter, with moderate amounts of powder snow mixed in with some dry periods and endless wind-buff days.
Steve Taylor – The Mammoth Snowman
PS The new runs of the ECMWF Seasonal come out for forecasters on the 5th of each month.
La Nina Years Snowfall Totals for Mammoth Mountain
Weak La Nina
1971-72 Snowfall Total = 268 with 139 in December
1984-85 Snowfall Total = 236
2000-01 Snowfall Total = 393 with 124 in February
2005-06 Snowfall Total = 578 with 4 100+ inch snowfall months
2008-09 Snowfall Total = 470 with 2 100+ inch snowfall months
2016-17 Snowfall Total = 617 with 245 January 163 February
2017-18 Snowfall Total = 262 with 142 in March
Moderate La Nina
1970-71 Snowfall Total = 255
1995-96 Snowfall Total = 321
2011-12 Snowfall Total = 263
2020-21 Snowfall Total = 244.5
2021-22 Snowfall Total = 260
Strong La Nina
1973-74 Snowfall Total = 306
1975-76 Snowfall Total = 197
1988-89 Snowfall Total = 251
1998-99 Snowfall Total = 323
1999-00 Snowfall Total = 382
2007-08 Snowfall Total = 333
2010-11 Snowfall Total = 668
2022-2023 Snowfall Total = 717 – Largest Winter Recorded over the last 100 years
ENSO Watch
Last Update from DWP Precipitation for Mammoth Pass & the Eastern Sierra
Most Recent Posts
*Mammoth Mountain and Eastern Sierra Weather is updated Sunday, Tuesday & Thursday by local Steve Taylor, the Mammoth Snowman. The goal is to provide detailed weather forecasts presented in an easy-to-read format. This isn’t a Hype, one-and-done model-run website. It’s just the basic facts from how I see it after 40 years of being involved in local weather and recreation. And yes, I use Weather Bell for my forecasting data.
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Author – Steve Taylor – The Mammoth Snowman – Over the last 30+ years, Snowman has spent countless hours studying and learning about Mammoth Mountain Weather and Snow Conditions first hand. He has been skiing around the hill with marked ski poles since March of 1991 so he can measure the fresh snowfall amounts out on the hill.
Snowman started blogging this information back in 1990 on the old Mammoth BBS system, then the RSN Forums, and then on to MammothSnowman.com in 2004 with Video and photo Blog reports. (There was No YouTube back then.) Facebook was added to the fold in 2008, and the Facebook Group was added in 2016.
Reports, videos, and photos from the website have been featured on local TV Stations here in Mammoth and Bishop, as well as KTLA, AP, Fox, ABC, CBS, and NBC News.
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