Arizona’s wildfire forecast is … complicated. Drought, climate change disrupt rhythms

• Drought and climate change have disrupted Arizona’s wildfire seasons, which used to peak just before the start of the monsoon.
• Forecasters feared a potentially catastrophic fire season this year, until a series of storms in March broke long dry streaks. Even now, the snow will only delay the season’s start.
• Years of suppressing wildfires have allowed forests to grow dense and full of fuels for fire. That means a lightning strike can ignite a fire that could burn across tens of thousands of acres.

There used to be a predictable rhythm to Arizona’s fire season. Dry and hot conditions as spring transitioned into summer brought the worst of the flames, charring landscapes across the region. The monsoon would bring a reprieve, and by mid-fall, the worst of the year’s fire danger would pass.

But not this year. 

Storms bypassed Arizona all winter. The last monsoon was sporadic. Almost no snow fell in Flagstaff and other high-country locations and by January, drought had settled into the lower elevations as well. 

Phoenix went 159 days without rain, the second-longest such streak on record. It was so dry in the high country that land managers lit prescribed burns in the dead of winter. 

Fire staff and meteorologists watched the forecasts with unease, knowing that an early and prolonged fire season was becoming more likely each day without snow on the ground. 

Snow finally fell in March — but only enough to buy fire managers a little time.

“This little bit of a reverse in fortune is super helpful, but it’s not going to be enough to shut down a potentially active fire season,” said Michael Crimmins, a climatologist for the University of Arizona. 

Crimmins predicts these “lucky” spring storms may have brought Arizona about three extra weeks before the start of an active fire season in April. The snowpack is too shallow, and any moisture acquired will melt into the parched soils or evaporate under the stronger spring sun. 

The peak fire season will continue until the start of the monsoon, which typically begins in late June or early July.

On March 31, the Arizona Department of Forestry and Fire Management appeared with Gov. Katie Hobbs for the 2025 wildfire briefing, warning of the potential for an extremely active and dangerous fire season, especially at higher elevation forestlands. 

“This is one of the most critical years we’ve seen in our careers,” said John Truett, fire management officer for the Department of Forestry and Fire Management. “We’re coming off several years of drought, and we’re experiencing very extreme dryness in our vegetation this year.” 

As climate change causes warmer and drier weather across the Southwest, fires can pop up year-round. But when will Arizona’s peak wildfire season occur, and how does the weather play a role? 

Firefighters and land managers are preparing for the worst, but through interagency and public efforts, they hope Arizona can get through this year’s fire risk largely unscathed. 

“The recipe is there for a significant fire season here in the Southwest,” said Richard Naden, a fire weather meteorologist for the Southwest Coordination Center. “The good news is that every week that goes by, that window gets smaller. Every week that goes by without significant impacts is a good thing.”

How is fire season in Arizona changing?

Humans repressed fires — good and bad — for a century, allowing forests to grow dense with fuels, and global warming and drought add to prime conditions for wildfires. Fires are now behaving more erratically, and this year is shaping up to be worse than usual.

Flames in the fire-adapted forestlands are burning hotter and have become more difficult to control, and fires are igniting in the lower deserts like never before. Desert ecosystems did not historically experience big wildfires, so when flames spark, cactuses and other vegetation are decimated. 

“We have a legacy of suppression across all the West,” Crimmins said. “We stomped out fires and didn’t have that natural fire cycle.”

Much of Arizona’s forests are overgrown without regular fire to keep tree density down. If a fire occurs, especially if trees are stressed following abnormally dry seasons, it will burn hot and high into the crowns of the trees. These “crown fires” are extremely difficult for fire crews to control; they can torch whole trees, even entire forests. 

Arizona’s fire seasons have turned into fire years with the potential for intense burns across the state, but the peak fire months remain largely the same. 

“Fire can burn in any month of the year, but there is still a peak fire season. That’s April, May and June,” said Donald Falk, a professor in the School of Natural Resources and the Environment at the University of Arizona. 

But those peak times can grow longer depending on background conditions. In the past, the primary fire season may have lasted about four to six weeks, but now it can range two to three full months with burns throughout the rest of the year, regardless of season. 

Falk said the window when the soil and plants are dry enough to burn starts earlier in the year and stretches later into the fall. If fires start early in the primary season, they have more time to grow and burn. 

Spring precipitation helped, but it won’t be enough

Although this year’s fire season will likely be more active than usual, spring storms delayed the start. Experts feared intense fires could spark as early as March, instead of the traditional April onset. 

“It’s classic Arizona where we just run dry in the winter and then have these weird shifts in March and April, and it will just change the whole story,” Crimmins said. “We got lucky.” 

Winter precipitation is essential to a functioning ecosystem in the high country. Winter storms bring snowpack across the higher elevations, and as temperatures rise moving into spring, snow slowly melts into the soils and runs off into the water supply through the state’s watersheds. 

This keeps the landscape moist through part of the spring, slowly drying out as Arizona enters its traditional fire season. 

March dumped 35.6 inches of snow in Flagstaff after months of minimal precipitation, bringing much-needed moisture to delay the onset of wildfire season. But totals are well below average, so fire danger still looms. 

Crimmins now expects high fire risk by the end of April, peaking around Memorial Day weekend. Spring winds pick up, allowing fire to carry, and conditions will get increasingly hot and dry until the onset of the monsoon. 

“This won’t stop fire season, but it will help to delay the onset of the peak fire season to get us closer to the monsoon,” said Rogers Trueheart Brown, a fire staff officer for the Coconino National Forest.

The onset of the monsoon effectively ends the peak fire season. The monsoon usually brings rain across much of the state. Temperatures drop slightly and humidity increases, so fire conditions ease. Fires decline, and although there may be lightning starts, the conditions for fire to strengthen and spread are absent. 

If Arizona has a weak or delayed monsoon, fires have longer windows to burn and grow, and the fire season will continue. 

“This puts a huge amount of pressure on the monsoon to come in at least on time to shut things down,” Crimmins said. 

Fire weather conditions mean fuels are ready to burn

While wildfires in the Southwest have intensified overall with longer seasons, some years are worse than others, depending on short-term and long-term weather conditions. 

Following months of short-term drought in the last year and amid a 30-year-long-term drought, fuels across the forestlands are drier than usual. 

“It’s all seasonality. We went into this fall with very dry conditions. All of that vegetation has dried and it’s about two to three weeks ahead as far as curing goes,” Truett said. “We’re looking at an earlier curing of the fuels and a longer duration of the fire season.”

Fuel amount and condition play a big role in any given fire season. While less rain can prevent highly flammable, annual grasses from growing in the lower deserts, it increases fire risk at higher elevations because the vegetation is drier and ready to burn. 

Overgrown forests have an abundance of fuels, and compounded by unusually dry weather, fire can easily spread through a landscape. 

While long-term weather conditions like drought can set up an active fire season, just a shift in the wind or a sudden rain shower can impact fire conditions day-to-day. 

“Weather is so important,” Falk said. “Hourly changes can produce a big event. Just a few hours or days of hot, dry and windy weather can set you up for a spreading wildfire.” 

Wind, humidity, temperature and atmospheric instability in the short term play a role in how fire starts and spreads.  

Fire managers are preparing for the worst

Fire personnel and meteorologists know the risks this year’s peak fire months will bring to Arizona, and they’re preparing as best as they can for an active season. 

Fires have already popped up across the state. An unusually early fire, the Horton Fire, burned over 8,000 acres along the Mogollon Rim northeast of Payson in December and January. As of April 18, a total of 346 fires have burned 5,975 acres across Arizona, according to the Department of Forestry and Fire Management. 

Land managers are treating forests across the state to minimize fire risk. The Department of Forestry and Fire Management, in collaboration with federal, state and commercial agencies, carries out mechanical thinning and prescribed burns. 

The department has treated over 23,000 acres since July and has a goal to treat 30,000 acres by the end of the fiscal year. 

“Fire does not care about lines on a map,” said Brown. “We’re doing everything we can within our power to be as proactive and prepared as possible. Folks should make sure they’re doing the same for not if, but when it happens.” 

Brown urged the public to be proactive in avoiding fire starts and preparing their property ahead of the fire season. 

Even if all of the fire conditions are present, it still takes an ignition to start a fire. About nine out of 10 wildland fires are started by humans in Arizona, according to the Department of Forestry and Fire Management. 

Arizonans living on the wildland-urban interface — areas where human development meets wildland areas — can protect their homes from fire by removing anything flammable around homes, trimming trees and vegetation and keeping roofs and gutters clear of debris. 

“The 10 years before a fire happens in someone’s community are far more important than the 10 or 15 minutes an engine may have at someone’s house before the fire gets there,” Brown said. “People need to understand that fire is part of the ecosystem. It isn’t if, it’s when it happens.”

As the state heads into active fire months, it’s all hands on deck. Despite federal funding and staffing cuts under the Trump administration, state officials said they are prepared to tackle this year’s wildfires. 

“Right now, it does not affect us on our staffing and resources,” Truett said. 

As of the March 31 press conference, Truett said they are on track to be fully staffed before the peak fire season begins.

But scientists like Falk fear that with potential cuts to weather and climatological services and research, fire weather will be harder to predict, making wildfires more difficult to combat. 

“We are totally reliant on the federal systems for predicting and monitoring weather,” Falk said. “If you’re trying to make predictions about where the weather is going, and you’re not getting the information you’re accustomed to, you’re going to be caught blind. It’s putting us in a very perilous situation.” 

Hayleigh Evans writes about extreme weather and related topics for The Arizona Republic and azcentral.com. Email her with story tips at hayleigh.evans@arizonarepublic.com.