Mammoth Mountain Weather Forecast & Discussion

October 10th, 2023 @ 8:42 AM – Good morning, currently you will find clear skies across Mammoth Mountain and all the way down to the Bishop area.

Up at the top of Mammoth Mountain here is a temperature of 31 with the wind flow out of the S @ 44 gusting to 55 MPH at times. Down in Mammoth Lakes, there is a temperature of 51, and down in Bishop there is a temperature of 57.

Over the next week here is what to expect weather-wise out on Mammoth Mountain and around the Eastern Sierra.

A weak low-pressure system will move through California and the Eastern Sierra over the next 48 hours. The result will be gusty winds in the high country along with cooling high temperatures region-wide. There is no snowfall expected with this low-pressure system.

Friday into the Weekend looks to be clear with temperatures in the area coming up about 5-7 degrees with lighter southwest winds expected. Should be the perfect weekend to check out all the peaking Fall Colors in the high elevations.

Basic Weather Forecast through Thursday: Temperatures out on Mammoth Mountain will be in the lower 50s with Mammoth Lakes in the upper 50s to lower 60s with Bishop in the mid to upper 70s.

Night-time lows will be in the mid 30s to upper 30s for the higher elevations with early morning lows down in Bishop in the upper 30s to lower 40s.

All high country locations above 6,000 feet should see a freeze by early Wednesday morning. The freeze is not expected to be deep enough or long enough to damage the Fall Color show

The wind forecast for the high country, the wind direction will be SW to West into Wednesday and then the wind direction will change over to flowing out of the NE into early Friday.

Wind speeds at the 9500-foot mark and above will be in the 25-40 MPH range with gusts to 45-55 MPH possible into Wednesday evening.

The SW flow returns by later in the day Friday with wind speeds in the 5-10 MPH range with gusts to 15-20 MPH over the higher elevations into Sunday.

PS: Fall Colors are peaking above the 9000-foot mark in most locations at this time. The lower elevations are all in the process of changing now with some good color starting to show in Bishop.

Snowman out...

Mammoth Lakes to the Eastern Pacific Satellite View - Mammoth Weather
Mammoth Lakes to the Eastern Pacific Satellite View

7-Day Temperature Forecast

5-Day Temperature Forecast - Mammoth Weather

7-Day Snowfall Forecast

7-Day Snowfall Forecast - Mammoth Weather

7-Day Wind Forecast

7-Day Wind Forecast - Mammoth Weather


Days 1-7 Forecast Discussion

October 10th, 2023 @ 12:15 PM – The next seven days are looking primarily clear, with no snow expected. Very typical weather for this time of the year, with some cooling from a weak inside slider followed by more ridging moving in on day 7.

Over the upcoming week, the weather looks great for an adventure; make sure to layer up if you’re out early, especially on Wednesday morning when a freeze is expected in the high county.

Let’s look at some weather data so you can get a visual of what is going on now.

In this first image, you can see the low-pressure system off the Pacific Northwest coast. This low will be an inside slider heading well to the east of the Sierra Crest. 

The  direction and position of the low will result in just a change in temperatures and winds. When an inside slider is this far to the East of Mammoth Mountain, you can expect it to be dry with no snowfall.

ecmwf deterministic - mammoth weather

In the two images below, you can see the system sliding to our east down into Utah and then through southern Colorado. This one is a quick mover, unlike the last hybrid slider we had a week ago that hung in the area longer. ecmwf deterministic - mammoth weather

ecmwf deterministic - mammoth weather

By the weekend, the ECMWF has the next low-pressure system set up off the Pacific Northwest coast; this system looks to hang out in that position for a time and will slowly bring in higher heights over the Eastern Sierra. This type of pattern means dry with season-average temperatures over the weekend. ecmwf deterministic - mammoth weather The GFS has cooler weather with lower heights exteneding inland from the main trough in the pacific northwest. This would results in a cooler windier weekend then the model above as. By next Monday, a strong ridge of high pressure will be just to the east of Mammoth Mountain. As the ridge nudges closer to the area, temperatures will increase, and winds will remain light. ecmwf deterministic - mammoth weather

8-16 Day Fantasy Weather Outlook

10-10-23 @ 12:24 PM – the 8-16-day fantasy forecast period looks dry and warm under a strong ridge of high pressure. There are no signs of any pattern changes during this period.

Weather like this is typical for this time of year and can last through October and beyond. Enjoy the calm before the first snows shut down the high country to biking and hiking.


Day 8-16 - ECMWF ENS 500 Height Anomaly
Day 8-16 - GEFS ENS 500 Height Anomaly
ECMWF ENS Temperature Anomaly Days 8-16



NOAA 6-10 Day Temperature Outlook for Mammoth Mountain and Mammoth Lakes
NOAA 6-10 Day Temperature Outlook for Mammoth Mountain and Mammoth Lakes
NOAA 6-10 Day Precipitation Outlook for Mammoth Mountain and Mammoth Lakes
NOAA 6-10 Day Precipitation Outlook for Mammoth Mountain and Mammoth Lakes

45 Day Ultra Fantasy Weather Outlook

10-10-2023 @ 1:24 PM – Looking at the weather trends in the ultra-long-range fantasy outlook charts, we see a change to cooler and showery conditions around the first whole week of November. 

Right now, we are stuck on a positive PNA pattern. So, hopefully, the forecast for the PNA continues to head towards negative as November approaches. Overall, the November Outlook has been dry in the ECMWF Ensembles, while the CFSv2 keeps showing at least average snowfall for November to a bit above average.

The models have some heavy wet base snow mixed in with decent to good snowmaking conditions into mid-November. With the Mammoth Mountain Fan Gun Snowmaking System on Broadway, snowmaking crews would have no problem opening a couple of runs by their set opening day.

Of course, this is all in the Ultra Fantasy Period; what gives us at least a bit of confidence is that all the long-range ensembles I look at show a period of wetness and cooler weather. Overall, that period of wetness looks to be nothing like the big storms we saw last season.

Remember, over the last 20 years, November have been much drier than a wet month, so anything we get should be considered a blessing. It seems like most years, some always make it through right before the 10th of November, so we will see what happens. Exciting times being a part of snow farming.

** The Fantasy and Ultra Fantasy Outlooks are “outlooks, not forecasts.”

Some years, the wet patterns that appear in the long-range pan out; others are always out in the fantasy period and never make it to the short-term forecast period. When all the models have agreement on wet or dry patterns, more often than not, they seem to pan out.

PNA Forecast Chart

Day 16 – 45 ECMWF Extended Ensemble Mean

45 Snowfall from the ECMWF Ext. Ensemble Mean

Temperature Anomaly – ECMWF Ext. Ensemble Mean

Precipitation Anomaly November 2023- ECMWF Extended Ensemble Mean

Precipitation Anomaly November 2023 – CFS Monthly


Longer Range 90 Day Weather Trends

ECMWF Seasonal Ensemble Mean Model 

This model seems to have the most likely outcome over the next three months. The one factor the model could be missing out on is if a Super Typhoon would get caught up in the westerlies in the latter half of October into early November. Those types of systems can quickly throw Fall into the above-normal precipitation range. With systems like that, there are high snow levels above 9000 feet or higher, just like we saw in late October 2021… confidence in this model’s outcome is low to moderate at best.

CFS V2 – Long Range 90 Day Precipitation Outlook – 10-5-2023

The CFSv2 that so many people love continues to flip flop from wet to dry to wet and dry again for the start of the season. Here are today’s run from November, December and January.

ENSO – El Nino / La Nine Outlook – September 26th, 2023

El Niño Update: The current El Nino is in the strong category. How the event affects Mammoth Mountain and the Eastern Sierra this winter is uncertain. There are a lot of variables with this particular El Nino event that have not been seen during other strong events. Take a look at the video below for more information.

There are not a lot of strong El Ninos to look back at, so it’s hard to trust any of the long-range data right now. Past El Niño winters have been slow to start, so don’t be surprised if the Eastern Sierra sees below-average rain and snowfall this Fall. 

The video below is new from Mike Discussing the most current El Nino Data. All the images in this section have been updated, with what’s the most recent on there as of 9-26-23.

> To note, El Niño winters can be slow to start, so don’t be surprised if the Eastern Sierra sees below-average rain and snowfall this Fall.

SSTA Mammoth Weather Forecast
SSTA Mammoth Weather Forecast

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