Monsoon season is ramping up across the West this week (as of July 14, 2026). Based on current conditions, historical analogs, and seasonal and subseasonal weather models, we are expecting an active monsoon season across the West for the mid to late summer of 2026. 

Monsoon Season Rainfall Outlook:

For the core monsoon season, from July through September, we are expecting above-average rainfall and thunderstorm activity for a large portion of the West, extending from the Southwest to the Central/Northern Rockies to the Sierra. 

Our highest confidence (relatively speaking for a seasonal outlook) for above-average mid to late summer rain is across Utah, Western Wyoming, Eastern Idaho, and Southwest Montana. 

All other areas outside of the shaded green areas have equal chances of above or below-normal rain from July through September. 

Monsoon Season Temperature Outlook:

Above-average summer temperatures are favored for much of the Northwest and West Central U.S., with the highest confidence across BC, Alberta, Washington, and portions of Oregon, Idaho, and Montana. 

There are equal chances of above or below normal temperatures across the Four Corners region and Southern California, as the monsoonal flow could potentially have a cooling effect at times.

Portions of the Central and Northern Rockies, in theory, should fit into this "neutral" signal as well, but a recent and ongoing record-breaking heatwave likely tips the odds slightly in favor of above-average temperatures for the July-September period as a whole in this region. 

Learn More → North American Monsoon, Explained

Current Conditions:

We saw some brief and early monsoon-like patterns at times in late June and early July, but it has not been until the past few days that a sustained monsoon pattern has started to develop.

On the heels of a record-setting heatwave across parts of the West in recent days, this monsoon pattern is coming in strong, and it looks like it is going to continue at an impressive clip through at least late July.

The image below shows projected precipitable water anomalies on Tuesday afternoon, July 14th. Precipitable water is a measure of water vapor in the atmosphere, with well-above-average anomalies indicating significant moisture, or "fuel", for thunderstorm development and rain potential.

Next Two Weeks (Through Late July):

Medium-range weather models, which go out to 15 days, have been dialed in on this pattern change to a monsoonal flow for quite some time, and the pattern is now coming together as expected.

The European Ensemble Model (average of 50 simulations of this model) is projecting above-average precipitation anomalies across a large portion of the West through July 29th:

The American GFS Ensemble Model is similarly projecting above-average precipitation across much of the West.

Longer-Range Model Projections:

Subseasonal (2-6 weeks) and seasonal (1-3 months) weather models have also been on board with an active monsoon this season.

It should be noted that model forecast accuracy and skill decrease the further out in time you get beyond 2 weeks, but they are still worth evaluating as run-to-run consistency over time, and consistency among multiple different models, can lead to somewhat higher confidence one way or another.

The European Weekly Model, which goes out to 46 days, maintains a strong monsoon signal across a large portion of the West between mid-July and the end of August, except for a dry signal across the Pacific Northwest, outside of the core monsoon region.

The European Model has the best skill among these subseasonal models, but the American GFS and Canadian Weekly Models have a similar look with a strong wet signal across the Southwest and the Rockies.

Going further out in time, we can look at seasonal weather models that cover the entire 3-month period from July through September.

The European Seasonal Model is also considered to have the highest skill among these seasonal models. 

This model is projecting a wet signal mainly west of the Continental Divide and into California, with a neutral signal across Colorado and even a dry signal across portions of New Mexico and Arizona. 

The European Model's seasonal outlook for July-September has some inconsistencies across these latter regions versus what its subseasonal model projects from mid July to late August, and this introduces some uncertainties to the outlook for Colorado, New Mexico, and Arizona.

Another model suite to consider is the North American Multi-Model Ensemble (NMME), which is a forecasting system comprised of a collection of seasonal models.

This model suite also has a strong monsoon signal for July through September across a larger portion of the Southwest and the Rockies as a whole. Similar to other models, this model suite also has a dry signal for the Pacific Northwest.

Subseasonal and seasonal models have a known dry bias when it comes to the monsoon, so the fact that nearly all of these models are projecting a wet signal for the monsoon this year across a large portion of the West is noteworthy.

Historical Analogs:

It's certainly useful to evaluate near-term, sub-seasonal, and seasonal weather models, but it's arguably even more important to consider an analog approach and to evaluate past seasons with oceanic, atmospheric, and climatic similarities to this year.

We considered several long-range climate signals to come up with a set of historical analog years that most closely resemble what is occurring in 2026.

The emerging strong, or "super", El Niño was a major consideration, but it was not the only factor that we considered. Some past strong El Niño years were better matches than others, when considering other factors, which we will discuss in this article.

It should be noted that no analog is a perfect match, but looking at multiple analogs with moderate to relatively strong matches can give us some clues about what is more or less likely this summer.

We found 4 strong analog matches for this summer that we factored into our forecast:

• 2023
• 2015
• 1997
• 1972

We also found 3 moderate analog matches that we also gave consideration to in our forecast: 

• 1991
• 1987
• 1982

Using only the analog approach, here is what we found for July to September precipitation anomalies when weighing the top 4 analog years twice, and weighing the moderate analog years once.

There is a clear "westerly focused" monsoon signal using this historical analog approach, which is something we had also hinted at in our initial Summer Weather Outlook that we published back in April.

It's also interesting to see that the historical analogs have a drier signal across Southern Arizona, while Colorado has a neutral signal throughout the state.

Another interesting signal to note is the wet anomalies across the Pacific Northwest when using the analog approach. This is in stark contrast to the subseasonal and seasonal weather models that are projecting a dry signal across the PNW. 

This wet PNW signal in the analogs is not related to the monsoon itself, as the PNW is typically too far outside of the monsoon region, but it does indicate that in past similar years, we have seen a higher frequency of low-pressure systems that bring meaningful rain to the PNW, mainly in late summer and early fall (highest signal being in September) near the end of this region's traditional dry season.

Next, let's take a look at the factors we considered in our analogs that can play a role in monsoon season rainfall across the West.

Strong to Very Strong El Niño:

It's no secret by now that strong El Niño conditions are currently present in the Equatorial Pacific Ocean, as this has been a source of widespread media coverage recently.

El Niño is rapidly strengthening this summer, and long-range projections still indicate this could potentially be a record-strong El Niño heading into the winter months.

Learn More → Could Upcoming Super El Niño Be Strongest Ever?

In the image below, sea surface temperatures are well above average across the Eastern and Central Equatorial Pacific Ocean, with the highest anomalies just off the coast of South America. This is a classic signature of an emerging strong to super El Niño.

El Niño has a complicated relationship with the monsoon.

In a classic monsoon setup, a summer high-pressure ridge builds over the Southwest and the Interior West, with subtropical moisture originating from the South Pacific and the Gulf of Mexico, as well as recycled moisture from prior rainfall in the Mexican Highlands, circulating around this high and building northward into the Southwest U.S.

During El Niño summers, an active subtropical jet stream can disrupt the typical monsoonal flow at times with various troughs setting up or moving across the Western U.S.

In our analog years, we have seen a tendency for more frequent troughing to set up near the West Coast, which can often bring moisture further north and further west at higher frequencies than what might occur during a typical summer.

One big wild card is the connection between strong El Niño summers and increased Pacific hurricane activity.

Pacific hurricanes can occasionally transport additional subtropical moisture into the monsoon circulation, acting as a boost to the monsoon that can lead to periods of heavy rain across parts of the West.

On rare occasions, tropical systems can even maintain tropical storm strength nearly (or all the way) into the Southern California and Arizona border regions, which can bring substantial moisture and rainfall to parts of the west. This happened with Tropical Storm (former Hurricane) Hilary during the El Niño summer of 2023, which contributed to substantial rainfall across portions of California, Oregon, Idaho and Montana.

The summer of 2026 is expected to have above-average Pacific hurricane activity, but potential impacts in the Western U.S. are highly conditional and dependent upon the track and strength of individual storms. 

Gulf of California Sea Surface Temperatures:

The narrow body of water between the Baja Peninsula and the mainland of Mexico is a key contributor to monsoon moisture surges into the Western U.S.

Above-average sea surface temperatures in the Gulf of California have been linked to increased frequency and intensity of monsoon surges. 

Sea surface temperatures in the Gulf of California have been consistently warmer than average since the fall of 2025, and this warm signal has only intensified since El Niño conditions began to emerge in the Equatorial Pacific. 

By itself, this consistent and strong warm Gulf of California signature favors an active monsoon.

Two of the strong analog years we evaluated, 2015 and 1997, involved an emerging "super" El Niño with warm Gulf of California sea surface temperatures. 

Pacific Decadal Oscillation (PDO):

The relationship between PDO and the monsoon is not entirely clear, but it's worth considering the PDO as a piece of the bigger puzzle.

The PDO is a long-term climate index based on sea surface temperature distributions in the North Pacific Ocean, and it tends to go through 20-30 year cycles, although short-term deviations within these long-term trends can also occur.

We are currently in a cool, or negative, phase of the PDO, which means that temperatures are cooler in the eastern North Pacific compared to the central North Pacific.

PDO does have a stronger relationship with ENSO (El Niño Southern Oscillation), as it can reinforce or potentially counteract a given ENSO phase.

Typically, a warm PDO reinforces an El Niño signal, and historically, it's not uncommon for these two to be "in phase" with one another.

However, during the summer of 2026, we have opposite phases as ENSO is in a warm (El Niño) phase and PDO is in a cool (negative) phase. This adds some uncertainty to the forecast.

Two of the strong analog years we evaluated, 2023 and 1972, involved a strong El Niño and a cool PDO. It is interesting that these two analogs occurred about 50 years apart.

Southern Rockies Preceding Winter Snowpack:

There is a connection between poor (or big) snow seasons and the onset of monsoon season in the West, though there are mixed signals about how much this impacts the overall strength of the monsoon.

Poor snow years tend to favor earlier monsoon season onsets, whereas big snow years tend to favor later monsoon season onsets.

Snowpack across the Southern Rockies was historically low this year.

The monsoon is not starting particularly early this year (the second week of July is about normal for a consistent monsoon onset), but it is coming in strong at the onset, and this has been predicted for a while.

It's possible that the poor snowpack in the West may have some connection to this, as more of the sun's energy during the spring and early summer has been used to heat up the land (and help build the subtropical high-pressure ridge, rather than being used to melt the mountain snowpack.

Monsoon Season Forecast Takeaways:

• Confidence is highest in above-average rainfall across the "Western Rockies," including Utah, Eastern Nevada, Western Wyoming, Eastern Idaho, and Southwest Montana. Both our historical analogs and long-range weather models are projecting a strong wet signal across this region, and there appears to be a noteworthy connection to El Niño summers in this region.
  
  
• Colorado, New Mexico, and Arizona have a slight above average rain signal, but there is some uncertainty. Most seasonal and subseasonal models have a strong monsoon signal emerging across this region, and we are seeing this short-term signal over the next couple of weeks as well.
  
  However, the historical analogs have more of a neutral signal, as there have been some El Niño years in which the favored monsoonal flow shifts further west and north of these areas more frequently than usual. 
• California has a slight wet signal across the Sierra and SoCal Mountains. These areas are right at the western edge of where we tend to see monsoonal moisture reach typically, and there does seem to be at least a slightly favored trend toward wetter monsoon based on long-range models and historical analogs.
  
  A big wild card in this region is tropical storm activity and behavior in the Pacific. There have been strong El Niño summers in the past in which tropical activity led to anomalous summer rainfall in California, but it takes a lot of things coming together just right for these events to occur. 
• Pacific Northwest and Western Canada Uncertainty. These areas, which are outside of the core monsoon region, have the lowest confidence forecast for July to September rainfall. The long-range models have a dry signal, but the historic analogs have a wet signal, mainly stemming from late August to September rain. 

Final Thoughts:

Keep in mind that every monsoon season is unique, and there will always be atmospheric factors we cannot anticipate even weeks in advance. Summer seasonal outlooks are generally more challenging to forecast and have lower accuracy compared to winter seasonal outlooks. 

Regardless of whether or not this turns out to be a "big" monsoon season for some areas, even just a short-term monsoon surge can lead to an increased risk of lightning when hiking in the mountains or flash flooding in the canyons, or even additional wildfire risk on the outer fringes of the monsoon.

Thanks so much for reading, and have a great rest of your summer!

Also, stay tuned for our winter season outlook for North America, which will be published in August.

Alan Smith