October 7, 2026

Here we are at the beginning of Fall and thinking about what kind of Winter we may have in the Sierra and Northern Nevada. I don't know about you, but I have been thinking about it a lot with all the hype about a "SUPER EL NINO". It is true, we will likely see a "Very Strong El Nino" this Fall and Winter, but if you look at the past data you will find that not all past Very Strong El Nino's have produced heavy precipitation in our region. We will get into those details soon, but first let's look back to the Summer of '26.

In general, the Summer was dry and very warm with elevated winds, but not unusual. At the Reno Airport we recorded 13 days where the temperature was 100° or greater, the 10 year average is 13.4 days, so it was just average. Here in Montreux the hottest day was 97° in August, we had temperatures exceeding 95° in June (96.4°), July (95.5°) and August (97.0°). In September the hottest day was 90.4°. Precipitation was meager, only .45" from June through September in Montreux. Reno had one thunderstorm in August that concentrated over the airport which produced 1" of rainfall. Although not official, I recorded 43 days from June through September where winds exceeded 15 mph and 21 days where it exceeded 20 mph. That's the stats, I my book it was a very nice summer except for a couple of short periods of uncomfortable heat.

Let's move on the discussing El Nino. First, here is a graphic of a typical El Nino pattern.

A typical El Nino brings warmer weather to the north and cooler, wetter weather to the south. Of course there is no normal, but we can look at averages. The Climate Prediction Center (CPC) a division on NOAA, Rates El Nino from weak to very strong. They publish volumes of data and graphical materials on El Nino since it is one of the most significant events impacting and modifying our weather each winter.

The above graphic is published each month. It displays the probability and type ( El Nino, Neutral or La Nina) for the next nine three month periods. As you can see by the October, most recent publication we are quite certain to have a El Nino winter. It begins to weaken in the March-April-May 2027 period. Based on this we can ascertain that we will see El Nino this winter and it is forecasted to be a very strong one.

Since 1950, when we began to track the El Nino Southern Oscillation (ENSO), made up of warm and cold water periods off the South America West Coast, there have been 27 El Nino events. The next graphic shows the average precipitation in regions of California including the Sierra of all 27 events by regions.

If you look at the third line from the bottom you will see the percentage of average for each region. I used arrows for the two Southern California regions which have the highest percentage, and we boxed the Sierras which are broken down into three areas. 8SI in the Northern Sierra from Lake Tahoe north to Lassen Park, 5SI, south of Lake Tahoe to south of Mammoth Lakes, and 6SI from Bishop to the southern end of the range. On a average El Nino year we can expect the southern third of the state to receive well above normal precipitation. Now lets look at a very strong El Nino year.

There have been four very strong El Nino events recorded (they are included in the average year table as part of the 27). The 1982-83 event and the 1997-98 event produced significant precipitation throughout the state. The 1991-92 event was well below average except in the southern most parts of the state and the Sierra was well below average. The most recent event in 2015-16 was dryer than than the average very strong El Nino year and similar to an average El Nino year in the Sierra.

So how does this shape up to a "normal year" of precipitation. I have data all the way back to 1922 for the three regions of the Sierra. A normal year no matter the type of ENSO event in the three regions are, Northern (8SI) 52.81", Central (5SI) 39.58" and Southern (6SI) 27.87" of precipitation. Since we are located in the Northern Sierra Region, not Reno, but the Mountains above Reno, here are the actual precipitation totals for the four events. 1982-83 = 89.61", 1991-92 = 36.24", 1997-98 = 82.87" and 2015-16 = 59.00". Just on pure statistic we have a 2 in 4 chance for a better than average year, a 1 in 4 chance for a below average year and a 1 in 4 chance of a normal water year.

ENSO isn't the only known ocean cycle to impact our climate. There is the Madden Julian Oscillation (MJO), Pacific/North American Pattern (PNA), Arctic Oscillation (AO), Pacific Decadal Oscillation (PDO) and of course Kelvin Waves. We have a very strong Kelvin wave building in addition to the El Nino. You can read more about Kelvin waves by clicking HERE. All of these will play a part in our weather this winter, the forecasts generally only look ahead two or three weeks, so they aren't much help this time of the year. The CPC publishes a three month look ahead each month, the latest is at the bottom of this blog, I post this every month on this site throughout the year.

Being sensitive to our surrounding environment, the gray squirrels have been very active this year preparing for winter, and just recently the trees have begun to shed their needles. We have had a dry summer and early Fall, I always consider that since early precipitation in September and October come mostly as rain, not helping to start the seasonal snowpack. We live in a semi arid climate, and we don't want to waste our limited precipitation as rain. The later the shift to wet, winter like conditions, the better chance we have of building a good snowpack in the Sierra.

One of the best forecasters I like to read just published their Winter forecast. They project that we could have a very big winter. Here is a graphic they just published.

This shows the split Jet Stream with a strong southern jet that will bring heavy precipitation, likely several Atmospheric Rivers into the West Coast. The next graphic is their snow projections against historical norms.

They forecast above average amounts of snow for most of the southwest, including the Sierra and east through Utah, Northern Arizona, New Mexico and Colorado. These areas had dismal snowpack last year and water levels in reservoir are at historic lows this Fall. Given all the information I have produced and what others who study our climate and weather, I am ready to summarize it into a forecast.

Here is our Winter forecast. October will mostly warm and fairly dry. We already know the first week is well above the seasonal temperature, in fact in Reno we broke a couple of high temperature records this week. Next week we will have a couple of days of colder, likely wet weather, but no big storms. Mid month temperatures look to be seasonal with a few days of possible precipitation. November will be a different story, it will feel more like winter with a mix of sunny days, then a system will move through and drop some precipitation for a couple of days. This will repeat most of the month every several days. By Thanksgiving the Ski Areas above 8000 ft. will have a decent snow pack to start the season. Lower it is likely to be questionable how much snow will fall at 6000 ft.. Communities like Montreux will likely have some snow, but it will quickly melt when the sun comes out. December will see a couple of big storms that will bring several feet of snow above 7000 ft. in the Sierra and measurable snow likely as low as 5000 ft. December is historically one of the coldest months. We could also see a possible white Christmas in Reno. In looking way ahead into 2027, the four Very Strong El Nino's that we discussed above, all had very significant precipitation in January and February, which is likely again this season and will be very helpful with our snowpack. All of the precipitation above 6000 ft. and will mostly likely come as snow. It is possible that we will have a brief January thaw that will raise snow levels for a week or so, but we will quickly return to winter conditions. Winter most likely will continue into early March. All in all this looks to be a very big winter in the Sierra and Foothills. I am very confident on the precipitation side, less confident on the temperature side, which is calculating the snow levels.

I recommend you make sure your snowblowers are tuned up if you live above 5000 ft, and for sure above 6000 ft. It is likely to be a very BIG winter!!

I will be away without my trusty laptop during the balance of October, beginning in November I will be updating of Blog regularly as we progress towards the winter months.

Check our daily report and the National Weather Service for updates. Our daily report on our weather station site, looks 3 to 5 days ahead.

Please comment, if you like, on our forecasts, your own observations, or anything else. Our email link is posted below.

Three month look ahead for October, November and December 2026.

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