June 18, 2025

By Jay Faught

When the summer months arrive in the Southwest, residents across New Mexico—and especially here in Santa Fe—start to anticipate the arrival of a familiar and vital seasonal shift: the Southwest Monsoon. Also known as the North American Monsoon, this annual weather pattern brings much-needed rainfall to our typically dry landscape and is essential for replenishing water sources, nourishing vegetation, and providing some relief from the summer heat.

The Southwest Monsoon is a seasonal wind and moisture pattern that develops each summer, primarily affecting the southwestern United States and northwestern Mexico. It’s marked by a dramatic increase in thunderstorm activity, higher humidity, and a noticeable shift in wind patterns that draw moisture into the region from the Pacific Ocean, Gulf of California, and sometimes the Gulf of Mexico.

Unlike the monsoons in India or Southeast Asia that bring weeks of steady, soaking rains, the Southwest Monsoon produces scattered, often intense thunderstorms that can develop quickly and bring heavy downpours, lightning, strong winds, hail, and even flash flooding—sometimes all in one afternoon.

The monsoon season typically begins in late June or early July and lasts through early September. In Santa Fe, we usually see our first true monsoon storms by the first or second week of July, with activity peaking in late July and early August. By mid-September, the pattern typically weakens and drier air returns.

However, the timing can vary each year depending on broader weather patterns like El Niño or La Niña, sea surface temperatures, and even lingering spring weather systems that delay the onset of the high-pressure ridge needed for monsoon flow.

The Southwest Monsoon is driven by changes in atmospheric pressure and temperature as summer heat builds across the region. Here's how it works:

• Heating of the land – As the sun beats down on the Southwest, the land heats up quickly, especially in desert areas. This creates a large area of low pressure over the interior Southwest.
• Shift in wind patterns – At the same time, a high-pressure system—often centered over the Four Corners region—begins to form in the upper atmosphere. This “monsoon ridge” helps steer moist air from the Pacific and Gulf regions northward.
  
• Moisture influx – As moisture-laden air moves into the Southwest, the intense surface heating causes the air to rise rapidly, creating towering cumulus clouds. This often leads to afternoon and evening thunderstorms that pop up with little warning.
  
• Local terrain effects – In Santa Fe and other mountainous areas, the landscape enhances this pattern. Mountains act as natural triggers, forcing moist air upslope and helping fuel stronger storm development.
  

In Santa Fe, the monsoon brings some of our most active and dramatic weather of the year. Our elevation and terrain play a big role in shaping local thunderstorm development. While storms can be hit or miss, the rain they provide is vital for reducing wildfire risk, replenishing soil moisture, and supporting gardens, trees, and wildlife that rely on summer rains.

That said, monsoon season also brings hazards. Flash flooding can occur quickly, especially in arroyos and low-lying areas. Lightning is frequent and can spark new wildfires or cause power outages. It’s important to stay weather-aware and take storm warnings seriously, especially during the peak of the season.

The strength and timing of each year’s monsoon can vary significantly. Some years, Santa Fe sees generous rainfall and lush, green landscapes. Other years, the monsoon may fail to deliver, leaving behind drought conditions and stressed vegetation.

But whether it’s a blockbuster monsoon season or a more modest one, this unique weather phenomenon is a defining feature of summer in the Southwest—and a vital lifeline for our high-desert home.

For localized updates on monsoon activity and daily weather forecasts tailored to Santa Fe, be sure to follow the Santa Fe Weather Facebook Group, where I post regular updates, storm outlooks, and helpful insights into what’s happening in our skies.