On the final Saturday in May, the midday temperature in the historic Delta town of Isleton climbed oppressively close to 100 degrees during what turned out to be a mini, late-spring heat wave in Northern California.
Related Articles
What visitors need to know before traveling to Yosemite this summer
5 Bay Area summer hikes to catch cool breezes and breathtaking scenery
Largest campground at Yosemite National Park to reopen after $26 million renovation
2 Bay Area cities among America’s best for sober traveling
Summer Road Trip Playlist: 15 great Bay Area songs to fuel your travels
Locals hoped that the legendary Delta Breeze would begin blowing in off the nearby Sacramento River to cool things down. A drop in the temperature would enhance a long-planned celebration: the grand opening of a new Main Street park dedicated to their town’s Asian American history.
“On days like this, you’re praying for the breeze,” said Judy Vandeventer, a 26-year Isleton resident. Her home on a levee road outside town overlooks the San Joaquin River, and the breeze — “nature’s air conditioner” — lets her throw open her windows and doors on summer evenings.
Watersports enthusiasts take advantage of the world-famous winds at Sherman Island, CA on Saturday, May 31, 2025. (Don Feria for Bay Area News Group)
Delta residents love to share their experiences with this summertime weather phenomenon, in all its complexities, and how it affects their daily activities and even their life choices. “The Delta Breeze is a real thing,” says Iva Walton, Isleton’s mayor.
The breeze originates in the Pacific Ocean, more than 50 miles away, and meteorologists and atmospheric scientists say it can bring a few degrees of relief on hot days to the millions of people who live, work and play in the Delta, a region that extends from Vallejo to Sacramento and Stockton.
Alas, the Delta Breeze didn’t reach Isleton in time for the May 31 event, and people made do, enjoying the Taiko drummers and other entertainers with hand fans under the shade of a large tent. But the wind was blowing pretty hard several hours later and about 12 miles to the southwest on Sherman Island.
Watersports enthusiasts take advantage of the world-famous winds at Sherman Island, CA on Saturday, May 31, 2025. (Don Feria for Bay Area News Group)
On the western tip of this low-lying island, near the confluence of the Sacramento and San Joaquin rivers, a dark sandy beach faces directly into the headwinds, which makes it a popular destination for kiteboarding, windsurfing, wing foiling and other water sports that depend on wind power. On the last day of May, it was also about 10 degrees cooler on the beach than it was in Isleton.
“It’s phenomenal here. It’s, like, why we don’t leave here in the summer,” said Emily Haw, a kiter from San Francisco, who was participating in an annual event to mark the start of the summer wind sports season in the Delta. Haw, who learned to kiteboard in Maui four years ago, has “chased the wind” to Brazil; New Zealand; Portugal and Cape Town, South Africa. But Sherman Island has “the best wind, honestly,” she said.
Watersports enthusiasts take advantage of the world-famous winds at Sherman Island, CA on Saturday, May 31, 2025. (Don Feria for Bay Area News Group)
This “phenomenal” wind starts in the late spring and is the result of cool, moist air currents from the ocean, according to Ian Faloona, an atmospheric scientist at UC Davis. As inland temperatures rise, the currents push in through two major openings in the coastal range: the Golden Gate and the Petaluma Gap, lowlands that run between Bodega and Tamales bays and Petaluma. From San Francisco and San Pablo bays, the cool air travels up through the Carquinez Strait, usually arriving in the Delta in the late afternoon.
“The micro-meteorology around the Bay Area is really complex, but generally speaking, you have the flow coming in off the ocean into that Carquinez opening and then filling the Sacramento Valley to the north and the San Joaquin Valley to the south,” Faloona said. The breeze often reaches Sacramento or Lodi and can extend as far north as Redding or south as Bakersfield. However, by the time it reaches these towns at either end of the valleys, it gets blocked by the surrounding mountains, where it tends to stagnate and heat up so that it “no longer feels cool and breezy,” Faloona said.
Watersports enthusiasts take advantage of the world-famous winds at Sherman Island, CA on Saturday, May 31, 2025. (Don Feria for Bay Area News Group)
Delta residents like to dish about micro-climates related to the breeze. It might be blowing at Vandeventer’s home, on the south side of Brannan Island, but not at her friend’s house 3 miles north, along the Georgiana Slough. Meanwhile, Sherman Island, closer to the Carquinez Strait, is likely to be breezy even when there’s not much wind upriver, as was the case in Isleton on May 31. “It’s always blowing” on Sherman Island, said Judy Vandeventer’s husband, Skip.
When the kiters gathered on Sherman Island for their event, wind speeds had reached 15 to 24 mph by about 4:30 p.m., enough for Haw and other serious kiters to participate in an “expression session,” a demonstration of their highest-flying, wind-aided, over-water stunts.
Several people at a time headed into the waves lapping onto the beach and let the wind catch their kites and pull them out on their boards. They raced across the surface of the water to gain speed and lift. Once in the air, they performed twists, flips and front and back rolls.
“It’s special here,” said Michaela Pilkenton, a professional Big Air kiter who traveled from Hood River, Oregon, for the Sherman Island event. “This is a light day. We usually prefer it a bit windier, but that’s why the Delta is really nice. The wind is usually like 18 knots (20 mph) and pretty consistent.”
Rana Eser catches air on her kiteboard while taking advantage of the world-famous winds at Sherman Island, CA on Saturday, May 31, 2025. (Don Feria for Bay Area News Group)
This consistency explains the presence of massive wind turbines, visible from Sherman Island, that now dominate the landscape of the low-rise Montezuma Hills, directly across the Sacramento River. Some 1,000 turbines, operated by several wind farms, have been credited with providing clean energy, creating jobs and benefiting the local economy.
But kiters say the massive, rotating turbine blades have slowed the flow and created pockets of turbulence further up the Sacramento River, near Rio Vista, where they used to gather before gravitating to Sherman Island.
As always, kiters “chase the wind.” That’s the case for Terri Henderson, president of the Rio Vista Windsports Association and one of the organizers of the opening day event. Henderson began wind surfing on the Delta in the 1980s, but has since switched to kiteboarding, which she said is easier on the body.
Rana Eser gains speed on the water in order to catch air on her kiteboard while taking advantage of the world-famous winds at Sherman Island, CA on Saturday, May 31, 2025. (Don Feria for Bay Area News Group)
A former Delta Dental employee who raised her two children in the East Bay suburbs, she and her husband have built their retirement around being near the best wind possible for kiteboarding. They live on the coast of Baja, California, during the winter, then return to their island home near Isleton in the summer. She likes to get out on the water as much as possible.
“When it’s 100 degrees in the valley and there’s fog on the coast, that’s the perfect mixture to get wind coming off the water,” Henderson said. While the breeze generally picks up in the afternoon, Henderson said, “There’s some days when it’s blowing in the morning and times when it’s blowing all day. It’s kind of amazing. We’re all just on hold, waiting for the wind.”
The dynamic mix of cool ocean air and hot inland temperatures affects the intensity and timing of the Delta Breeze, according to Dakari Anderson, a meteorologist with the National Weather Service. “You need the valley to be hot enough where it actually creates the effect,” he said.
Watersports enthusiasts take advantage of the world-famous winds at Sherman Island, CA on Saturday, May 31, 2025. (Don Feria for Bay Area News Group)
It’s the pressure differences between hot inland temperatures and cool coastal temperatures that bring the wind up through the Carquinez Strait, Faloona added. “So you’ll often get the peak temperature difference around 4 o’clock, but you might get even stronger winds a couple hours later, and then gradually, that will decrease and weaken that pressure gradient force which is pushing that air on shore,” Faloona said. “And in the middle of the night, it’s generally when the winds are weaker, because that temperature difference has shrunk.”
Much of the talk about the Delta Breeze these days also focuses on how it might be affected by climate change. Faloona said the increasing frequency of 100-plus-degree days inland could mean that the Delta Breeze will grow stronger.
Meanwhile, Delta residents will continue enjoying this weather phenomenon when they can. When the wind starts blowing up from the Carquinez Strait, “it just kind of rolls right over the levee and down Main Street,” said Walton, who also owns the popular Mei Wah Beer Room in Isleton.
The breeze is especially welcome on Sundays, when the beer room hosts live music outside on its patio. Walton said: “The other day it was in the mid-80s, but with that breeze, it was just like, ‘What a perfect day.’”
