A prolonged and unusual March heat wave is gripping cities across the West

It's a stark contrast to the Midwest and eastern half of the country, which are digging out after powerful snow storms that led to thousands of flight cancellations this week.

Dogs and sunbathers flocked to Crissy Field's shoreline on the north end of San Francisco, as the Golden Gate Bridge shimmered nearby. It’s unusual for San Francisco to get this hot this early, said Roger Gass, a meteorologist with the National Weather Service in the Bay Area.

It last happened in 2005, when downtown hit a record 87 F (30.5 C) on March 11, part of a two-day heat wave and its record high for the month. In March 2004, the city saw a nearly weeklong heat wave with temperatures around 80 F (26.7 C).

On Tuesday temperatures in the city looked to tie the record.

“It feels like summer already in March. That’s crazy, but I love it," said dog walker Justyce Roliz.

But resident Jessica Ling noted one challenge for San Franciscans: Most don't have air conditioning.

“We have our fans going, our windows open, but we try to be outside as much as we can,” she said.

Some tourists are enjoying the warm weather

Elsewhere, cities that are more accustomed to sweltering weather were hitting their own unusually high spring temps. In Las Vegas, there's a chance temperatures could reach 100 F (37.7 C) Saturday, said meteorologist Brian Planz at the city’s National Weather Service forecast office. That would be the earliest Las Vegas has reached triple digits. Even if temps stay in the double digits, the city is poised to break its March all-time high of 93 F (33.8 C), set back in 2022, he said.

“If people are visiting Vegas this weekend, they just need to prepare for the heat, make sure they’re hydrating,” he said. “This is going to be unusual for this time of year.”

Mark Reeves was heeding the advice, drinking plenty of water, staying in the shade and occasionally dipping into the many air-conditioned casinos. The visitor from New Zealand, who was standing in front of the famous Fountains of Bellagio, said he didn't think it would be this hot.

But the heat hasn’t dampened his trip.

“For me, this is the trip of a lifetime,” he said. “I’ve never been to the USA before and I may never get here again.”

Johnnie and Darien Anderson were happy to exchange the cold weather in Little Rock, Arkansas, for the dry heat in Las Vegas to celebrate their wedding anniversary. They noted it is less humid than Arkansas in the summer.

Meanwhile, some Western national parks that were preparing for spring break crowds urged people to check the forecast before heading out. High temperatures at White Sands National Park in New Mexico could reach the mid 90s F (around 35 C). Grand Canyon National Park in Arizona was under an extreme heat warning, with temperatures possibly hitting 104 F (40 C) in some places. The message from park officials: Avoid strenuous hiking during the hottest part of the day, which they identify as 10 a.m. to 4 p.m.

Some cities warn against water waste

Denver hasn’t seen three consecutive March days above 80 F (26.6 Celsius) since 1907, but it could happen again this week, the National Weather Service said.

The heat wave comes at the end of an unusually warm winter that has led to a lack of snow in Colorado's mountains, which provides the water for millions of people. Water providers in the Denver area have already enacted or are considering limits on the number of days people can water their lawns. They’re urging people not to be tempted to turn on their sprinklers this month.

Shonnie Cline, a spokesperson for Aurora Water, which provides water to 400,000 people in suburban Denver, said it’s possible temperatures could still drop below freezing later, causing any water left in sprinkler systems to freeze and break the lines.

“The sooner you wake it up, it’s not necessarily better,” she said of lawns.

Associated Press journalists Jessica Hill in Las Vegas, Colleen Slevin in Denver and Susan Montoya Bryan in Albuquerque, New Mexico, contributed to this report.