As the thermometer creeps higher, moving from sizzlin' to blazin' all over the Bay Area, the National Weather Service has some advice.
"Drink water, not beer," forecaster Diana Henderson said.
Drinking an ice-cold brew on a hot day may seem as natural as putting on sunscreen -- which is strongly recommended if you're going to be out in the sun on Wednesday -- but with temperatures expected to crack 90 degrees in San Francisco, the mid-90s in Alameda and Santa Clara counties and the 100s in some parts of Contra Costa County over the next two days, Henderson offered a reminder that heat and alcohol don't always mix.
"It's really important to stay hydrated, and drinking can have the opposite effect," she said. "And in heat, it can hit you hard."
The spring heat wave that rolled in Monday is expected to peak Wednesday, when an excessive heat warning issued by the weather service expires. The warning went into effect at 1 p.m. Tuesday and lasts until 8 p.m. Wednesday.
Henderson said most of the heat-related records were expected to fall Wednesday, among them the 109-year-old mark of 94 degrees in San Jose, set on May 14, 1905. On Wednesday, the high temperature there is expected to reach 96, Henderson said.
As for Tuesday, San Francisco hit a record 90 degrees, the highest for May 13 in the city since the National Weather Service began recording temperatures in 1927. On Wednesday, temperatures will continue climbing and are expected to reach 92. At San Francisco International Airport, Tuesday's 89-degree high was 1 degree shy of the 1976 mark, and the expected high of 93 on Wednesday will break the mark of 87 set in 2006, Henderson said.
In San Jose, Tuesday temperatures reached 95 degrees but fell short of the 99-degree record set in 1976. Downtown Oakland hit 93, tying a mark set in 1976.
Livermore hit 94 degrees on Tuesday and was expected to reach 100 on Wednesday. The gauge was expected to hit 103 in Gilroy, which would match the record set in 1976.
"If we don't break records, we're going to get awfully close," Henderson said. "Don't go jogging at noon."
On Tuesday, 128 professional bicyclists and even more fans bore the heat during the third stage of the Amgen Tour of California. The riders biked 108.5 miles from the Lake Cunningham Regional Park in San Jose to Mount Diablo State Park near Walnut Creek.
The high temperatures weren't making the air very pleasant, either; the Bay Area Air Quality Management District issued a summer Spare the Air alert for the second straight day because of the amount of smog in the air. People sensitive to unhealthy air, such as those with asthma and other breathing difficulties, were advised to limit their time outdoors, particularly in the afternoon. A third consecutive Spare the Air has been issued for Wednesday.
Then there's the drought, the worst in California since 1976, when many of the heat marks were set.
"There's not a cause and effect, but the hot weather is going to have an effect in the way water evaporates in the reservoirs," Henderson said. "So it's not good for things."
Henderson said a cool-down is expected Thursday, when a tropical pressure system will break through the high-ridge bubble that has forced temperatures higher, Henderson said. Temperatures will cool down by 5-10 degrees in most of the Bay Area on Thursday and Friday and are expected to be in the 70s when the weekend arrives.
Staff writer Karina Ioffee contributed to this report. Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH.
As temperatures soar, many Bay Area communities are opening facilities to help those who are particularly sensitive to the heat stay cool.
Contra Costa County
San Mateo County
Santa Clara County