In This Update:

• What Is the North American Monsoon? Why Does It Matter?
• How Does the Monsoon Impact Drought in the Southwest?
• What Is the Drought Status Going into the North American Monsoon?
• Will the North American Monsoon Be Active through September? What Does This Mean for Drought?
• Additional Resources

What Is the North American Monsoon? Why Does It Matter?

• The North American Monsoon brings summer precipitation to parts of the Southwestern U.S. and Mexico, typically beginning in mid- to late June and lasting through September. This pattern results in active thunderstorms across Arizona, New Mexico, Colorado, and southern/eastern Utah. Monsoonal surges can also occur outside of these "core" areas, reaching Nevada, southeastern California, Far West Texas, and Wyoming.
• The North American Monsoon is a seasonal wind shift that occurs between June 15–September 30, depending on geographic location. The monsoonal flow allows moisture to move into the Southwestern U.S., which provides a needed ingredient for thunderstorm activity.
• The development of a ridge of persistent high pressure near the Four Corners region in the Southwest often initiates monsoon activity by providing a more moist, southerly flow from the subtropics around North America. Learn more about monsoon dynamics.
• The monsoon can vary in intensity and location from year to year. A more active monsoon season can moderate hot conditions with more thunderstorm activity, increase soil moisture, and reduce land surface temperatures, and improve drought conditions. 

How Does the Monsoon Impact Drought in the Southwest? 

• Rainfall associated with the monsoon is very important for the Southwest U.S. Parts of Arizona and New Mexico receive as much as 10-60% of their annual precipitation during the monsoon season (data for June-August).
  • The position of the high pressure system can shift throughout the season, which determines if Arizona or New Mexico will get more or less rain. This can sometimes result in rapid drought improvement or onset.
• A weak or inactive monsoon season can worsen short- and long-term drought conditions. For example, the inactive 2023 Monsoon Season resulted in significant drought expansion for New Mexico and Arizona. Meanwhile, an average to above-average monsoon can potentially improve or remove drought conditions, such as the 2022 North American Monsoon, which was the 9th wettest on record and significantly improved drought conditions in Arizona and New Mexico.
• The monsoon has a lesser influence in Nevada and California, though areas of southern Nevada and southeastern California occasionally receive significant monsoonal precipitation. On average, 20-25% of southern Nevada’s precipitation falls during the summer.
• Even in states where an outsized portion of annual water supply is derived from snowpack, monsoonal rainfall can still meaningfully reduce local impacts. For example, monsoonal precipitation can reduce demand for water stored in reservoirs, recharge groundwater, benefit agricultural production by improving grassland health for livestock and filling stock ponds, and reduce wildfire risk.

North American Monsoon Precipitation Is a Major Contributor to Southwestern Annual Rainfall

What Is the Drought Status Going into the North American Monsoon?

• As of June 24, every state in the Southwest (and California) is experiencing some level of drought (D1-D4), according to the U.S. Drought Monitor :
  • 97.33% of Arizona
  • 39.29% of California (primarily in southern California)
  • 45.47% of Colorado
  • 50.60% of Nevada
  • 80.20% of New Mexico
  • 91.10% of Utah
• National Weather Service offices throughout the Southwest have issued drought information statements describing local drought conditions and impacts, including for:
  • South-central and southwest Arizona and southeast California (NWS Phoenix)
  • Western Colorado and eastern Utah (NWS Grand Junction)
  • Mojave Desert and eastern Sierra (NWS Las Vegas)
  • Utah and Uinta County, Wyoming (NWS Salt Lake City)
• In Arizona and New Mexico, drought conditions have expanded since summer 2024. Drought intensified and expanded northward and westward into southern Nevada and California due to a dry summer in 2024 followed by a dry fall and winter. Some areas (e.g., Arizona, southern California, and Nevada) saw slight improvement this spring, but drought persists.
• Looking back 12 months to the start of the last monsoon (June 2024) until now (May 2025), Arizona experienced its 3rd driest and Nevada its 13th driest June–May,  going back 130 years. Some areas were worse at the county scale. Yuma and Maricopa counties in Arizona; Imperial County, California; and Clark County, Nevada experienced June-May periods in the top three driest on record.
• Utah, New Mexico, and the Navajo Nation have already declared drought emergencies. 

Widespread Southwestern Drought at the Start of Monsoon Season (June 24, 2025)

Low Statewide Precipitation Over the Past Year

Will the North American Monsoon Be Active through September? What Does This Mean for Drought?

• Seasonal forecasts of monsoon precipitation are largely based on continental or global-scale influences (e.g., sea surface temperature patterns), while actual rainfall totals for a given location are influenced by local-scale factors (e.g., local landscape, humidity, and temperatures), some of which can change quickly and over short distances. As a result, there is greater uncertainty in monsoonal precipitation forecasts for specific locations than when considering the Southwest region as a whole.
• The Southwestern U.S. is forecast to be wetter than normal through at least mid- to late July. However, precipitation in the first half of July is not a predictor of precipitation during the rest of the monsoon season.
• For the 2025 Monsoon Season, NOAA’s Climate Prediction Center’s seasonal outlooks favor above-normal temperatures and equal chances of below-normal, normal, and above-normal precipitation across most of the Southwestern U.S. An “equal chances” outlook does not necessarily mean normal, or average, rainfall can be expected. Rather, it implies that there is nothing in the climate system (including the El Nino-Southern Oscillation, which is currently neutral) that is pushing weather patterns toward one extreme or the other and any scenario is possible.
• Drought is predicted to persist in much of the region over the next month and the summer months, with potential drought improvements (but not removal) in the “core” monsoon region at the Arizona-New Mexico border.
• Given these outlooks, wildfire risk is forecasted to be near normal for parts of the Southwest that normally have good summer precipitation from the monsoon.
• For short-term forecasts, see the Quantitative Precipitation Forecast (QPF) or your local National Weather Service Weather Forecast Office.

Odds Favor Wet Start for the Monsoon through Mid- to Late July

Drought Predicted to Improve in Parts of Arizona/New Mexico in July, But Otherwise Persist 

Potential Impacts of North American Monsoon Precipitation for Drought