By late afternoon, the temperature at Ronald Reagan Washington National Airport had risen to 99, with a heat index of 106. It was even hotter on the steaming pavement downtown. In New York, the temperature rose to 101 at LaGuardia Airport and 96 in Central Park. Philadelphia and Baltimore climbed into the upper 90s.

The National Weather Service posted heat advisories and warnings from Maine to Oklahoma. Forecasters said the heat would linger until Thursday night, when a cool front was expected to bring temperatures down into the 80s.

Thousands who made it through the heat of a day found themselves in the dark Wednesday night after thunderstorms downed trees and power lines in parts of Massachusetts. Most of the power was expected to be restored overnight.

At the Capitol, tourists filled water bottles at drinking fountains and doused themselves. Others drenched their baseball caps before putting them on.

At the Library of Congress daycare center, children stayed inside because it was deemed too hot to swim. Washington Redskins coach Joe Gibbs cut his players a break by pushing back their 4 p.m. practice session to 7 p.m.

"It's unbearable, it's oppressive," said Joy Haber, 44, who canceled a trip from Long Island into Manhattan because of the stifling weather. Her 13-year-old son, Sean, skipped day camp when his bus arrived with a malfunctioning air conditioner.

New York Mayor Michael Bloomberg said the city was fortunate that no fatalities were linked to the brutal weather. Subway riders were in for a sweltering commute - the temperature was about 111 at a Pennsylvania Station platform.

The city's electric utility, Con Edison, set its second record in two days for peak electricity demand, surpassing the level from a day earlier. The Long Island Power Authority also set a record.

The Dixie Chicks postponed their Wednesday night show at the outdoor Jones Beach Theater on Long Island because of the scorching heat.

In Philadelphia, concrete worker Bob Ferguson was building walls 32 feet below street level. "Down in that hole, there's no air," said Ferguson, who wore the mandatory hard hat, long sleeves, long pants and work boots.

Bicycle messenger Gravett Dhuja tried to look at the bright side as he rested near a Capitol Hill office building: "It's been hot, but rain is a lot worse for us."

Authorities in the capital were prepared to go door to door to get people to public cooling centers, said Mark Brown, deputy director of the D.C. Emergency Management Agency. The city also passed out fans to low-income residents and kept its homeless shelters open around the clock.

The same heat wave was blamed for as many as 164 deaths last week in California.

In Kentucky, an 18-month-old boy was found dead Wednesday inside a van about 60 miles northeast of Lexington. The vehicle's doors were locked, and the boy's mother had to break a window to get to the child, authorities said.

Norfolk Naval Station in Virginia hoisted black flags at gymnasiums and ports to caution sailors against doing strenuous exercise outdoors.

In Boston, animals at the Franklin Park Zoo were kept cool with sprinklers and frozen treats. The African wild dogs and lions got frozen blood; the primates received frozen fruit juice.

"It's a matter of taste, I guess," zoo President John Linehan said.

Boston authorities awaited autopsy results on a pregnant woman who died Saturday after collapsing at a sweltering Red Sox game. Denise Quickenton, 29, suffered an apparent heart attack after sitting in sunny bleacher seats where the temperature was at least 90 degrees, officials said. She was seven months pregnant, but a medical team was able to deliver her 4-pound infant at a hospital.

Some Washington tourists pressed on with their plans, gulping bottled water and fanning themselves with brochures outside such landmarks such as Union Station and the Washington Monument.

"The humidity is so bad - not like in Spain," said Carlos Mulas, 56, of Madrid, before boarding a tour bus. "But Washington is so beautiful. We expect to enjoy it."

Several members of tourist Gregg Selewski's extended family spent their nights in a recreational vehicle parked at a campground in Greenbelt, Md. They vowed to see everything, despite the heat.

"This is what we came to do," said Selewski, 13, of Canton, Mich.

The watch meant hurricane conditions of winds of at least 74 mph were possible by late Thursday.

Some 600 tourists evacuated Culebra and Vieques, islands off Puerto Rico's east coast.

"Everybody left," said Jacinto Jiminez, owner of a hotel on Culebra.

Forecasters feared the tropical storm could still strengthen and could hit anywhere from south of Cuba to Florida by late this weekend.

Royal Caribbean, the cruise line operator, said it was changing the itineraries of three ships - the Navigator of the Seas, the Explorer of the Seas and the Freedom of the Seas - to keep them clear of the storm.

"Royal Caribbean will continue to closely monitor weather conditions," the company said.

Trevor Basden, senior meteorologist with the Bahamas' National Emergency Management Agency, said he expected Chris to strengthen into a weak hurricane as it passed through the island chain. He said the storm was likely to reach the Bahamas on Friday morning.

Bahamian officials advised people to stock up on water and canned food and be prepared to take precautions - such as boarding up their houses - if the storm reaches hurricane strength.

There were no reports of major damage or injuries as the storm skirted the Leeward Islands.

In Anguilla, Chris brought heavy rain and strong winds overnight but the storm was much less severe than expected because it shifted to the north at the last minute, said Elizabeth Klute, director of the disaster management agency for the British Caribbean territory.

"It just kind of skirted us," Klute said. "It's moving on."

Islanders in Antigua and St. Maarten awoke to a light rain. There were no reports of major flooding or other damage.

The first named storm of the 2006 season, Tropical Storm Alberto, swept over Florida in mid-June, then plowed northward along the U.S. coast past the Outer Banks. It was blamed for one death.

Last year's hurricane season was the worst in more than 150 years of record-keeping. A record number of tropical storms and hurricanes formed, including the devastating Hurricane Katrina.

Torrential rains have caused flooding along the southern coast, including the town of George in the Western Cape province, where a rain-swollen river swept a car from a bridge. Police recovered two men and two children who had been inside the vehicle, but rescuers were looking for a fifth person believed to have been in the car.

Homes were flooded, sending scores of families to seek shelter at a community center and school, local authorities said.

Heavy snow, rain and falling rocks closed mountain roads in parts of the interior, including a border post with Lesotho, according to local news reports.

The George airport was closed Tuesday, disrupting 24 flights before it reopened Wednesday morning, airport officials said. Passenger trains in the Western Cape were running up to 14 hours late, the Spoornet rail company said.

Meteorologists were investigating whether a severe storm that swept through the northern town of Dullstroom on Tuesday night was a tornado. At least six people were injured in the heavy winds and rain, which also ripped roofs off homes, police said.

Astoria grocer Salm Ali, who lost $17,000 in produce during the big blackout, felt a familiar sickening sense as he threw away $5,000 worth of produce Wednesday morning. His Liberty Deli and Grocery lost power Tuesday night and was only getting sporadic electricity the next morning.

"This is the life," he said sarcastically. "Even the fan isn't working."

Neither were the air conditioners or the refrigerators. Consolidated Edison reported about 1,200 residents in Astoria lost power overnight and nearly all had electricity restored by Wednesday afternoon as the utility's trucks turned out in force around the neighborhood. The last blackout affected 100,000 residents in northwest Queens.

Anthony Giannole, manager/owner of a Sunoco gas station on Astoria Boulevard, said the last power outage cost him $8,000 in business. The repair work on Wednesday blocked access to his station, once again hitting him in the wallet.

"I can't sell any gas because of our friends at Con Edison," said Giannole. "It's getting very annoying."

But power outages were sporadic and spaced out despite temperatures that soared to 101 degrees in the afternoon at LaGuardia Airport, a short hop from Astoria, and 96 degrees in Central Park, where the record for the date was 100. On Long Island, the temperature hit 97 in Islip, while White Plains in the northern suburbs was at 96.

The heat index, a measure of temperature plus humidity, made it feel like 107 degrees in Central Park. Mayor Michael Bloomberg said the city was fortunate that no fatalities were linked to the brutal weather. Straphangers were in for a sweltering commute -- the temperature was about 111 at a Pennsylvania Station subway platform.

Con Edison set a record for peak electricity demand, reaching 13,141 megawatts, enough electricity to power about 13 million homes, at 5 p.m. Wednesday; that topped the 13,103 megawatts a day earlier. The Long Island Power Authority also set a peak hour summer record of 5,736 megawatts.

By Wednesday evening, 5,674 Con Edison customers -- about 23,000 people -- were without power in Westchester County, the Bronx and Queens; Con Ed was trying to restore power and figure out why it went out. On Long Island, about 2,200 outages were reported.

The heat was taking its toll on residents.

"It's unbearable, it's oppressive," said Joy Haber, 44, of Woodbury, who canceled a trip into Manhattan because of the stifling weather. Her 13-year-old son, Sean, skipped day camp when his bus arrived with a malfunctioning air conditioner.

They weren't the only ones staying home. The platinum-selling Dixie Chicks postponed their Wednesday night show at the outdoor Jones Beach Theater due to the sweltering conditions. There was no word on a makeup date.

In the Riverdale section of the Bronx, 175 senior citizens were evacuated Tuesday night when the power went out at the Atria adult living facility, authorities said.

The National Weather Service again posted warnings for excessive heat and air stagnation due to the stifling humidity. Temperatures overnight were only expected to drop into the upper 80s, with another brutal day of heat expected Thursday.

Con Ed CEO Kevin Burke met for an hour with Bloomberg at City Hall, where they discussed the company's preliminary report on the earlier Queens blackout. The report offered no conclusions on the cause of the outage, although Bloomberg said the city will press the utility for answers.

"Am I satisfied with it? Of course not," Bloomberg told a news conference at which he promised the heat would soon be on the utility.

"We will find out what happened, get to the bottom of this and we will hold Con Ed responsible," said the mayor, adding that he planned to bring in outside investigators.

Burke, speaking later Wednesday, said the utility had no problem with that.

"We'll take all the help we can get," Burke said.

Community outreach teams were patrolling the streets, looking for homeless people and encouraging them to head to air-conditioned drop-in centers, carrying water and checking for dehydration. City officials reported a 20 percent increase in calls to the Emergency Medical Service on Tuesday, a 10 percent jump in police 911 calls and a 50 percent increase in fire calls. City firefighters on Tuesday responded to 1,800 fires, most of them minor.

Nearly a quarter-million people flocked to city beaches to beat the heat. The problem, according to Bloomberg, was many went home and then flicked their air conditioners on. While power demand usually decreases when the sun goes down, the opposite occurred in the city Tuesday night.

From 2001 to 2005, on average nearly 30 percent of the nation had "much above normal" average summertime minimum temperatures, according to the National Climatic Data in Asheville, N.C.

By definition, "much above normal" means low temperatures that are in the highest 10 percent on record. On any given year about 10 percent of the country should have "much above normal" summer-night lows.

Yet in both 2005 and 2003, 36 percent of the nation had much above normal summer minimums. In 2002 it was 37 percent. While the highest-ever figure was in the middle of America's brutal Dust Bowl, when 41 percent of the nation had much above normal summer-night temperatures, the rolling five-year average of 2001-05 is a record - by far.

Figures from this year's sweltering summer have not been tabulated yet, but they are expected to be just as high as recent years.

And it is not just the last five years. Each of the past eight years has been far above the normal 10 percent. During the past decade, 23 percent of the nation has had hot summer nights. During the past 15 years, that average has been 20 percent. By comparison, from 1964 to 1968 only 2 percent of the country on average had abnormally hot nights.

"This is unbelievable," said National Climatic Data Center research meteorologist Richard Heim. "Something strange has happened in the last 10 to 15 years on the minimums."

But it is not surprising because climate models, used to forecast global warming, have been predicting this trend for more than 20 years, said Jerry Mahlman, a climate scientist at National Center for Atmospheric Research and a top federal climate modeler.

It is a telltale sign of global warming, Mahlman said: "The smoking gun is still smoking; it's not shooting people yet."

One reason global warming is suspected in summer-night temperatures is that daytime air pollution slightly counteracts warming but is not as prevalent at night, said Bill Chameides, a climate scientist for the advocacy group Environmental Defense.

The records for summer-night low temperatures are part of a U.S. Climate Extremes Index developed by the National Climatic Data Center. Last year, in large part because of record hurricane activity, saw the most extreme weather in the United States since 1910.

The temblor struck just after 8 p.m. about three miles west of Glen Ellen in Sonoma County and 42 miles northwest of San Francisco near the Rodgers Creek Fault, the U.S. Geological Survey said. It was followed by a magnitude 2.0 aftershock about an hour later.

There were no initial reports of serious injuries or damage, according to a Sonoma County Sheriff's dispatcher. But several businesses and residents near the epicenter said Wednesday's quake sent some items tumbling to the floor.

At a Big-O Tires store in Rohnert Park, about 6 miles east of the epicenter, a fire extinguisher fell from the wall and onto a water pipe, causing some minor flooding.

Some pictures in the Benziger Family Winery gift shop in Glen Ellen fell from the walls, but the quake was just a "typical California" occurrence, said Brian Catlett, Benziger's assistant tasting room manager.

"Some pictures fell off the wall, wine shifted a little bit - nothing major," Catlett said.

The earthquake was widely felt as far north as Cloverdale and more than 80 miles to the south in San Jose, according to the USGS.

Steve Walter, a USGS seismologist in Menlo Park, said it was fortunate the quake did not actually occur on the Rodgers Creek Fault, the northern extension of the dangerous Hayward Fault, which many say is due for a major rupture.

"Rodgers Creek is capable of a large earthquake ... a 6.7 or larger," Walter said.

The volcano quaked with a 3.6-magnitude temblor at 2:34 a.m. Monday, which follows two other 3.6-magnitude quakes and a 3.5-magnitude quake over the past two weeks. Scientists suspect that the movement represents a lurching upward of the massive new lava spine evolving on the crater floor.

"We've been seeing these kinds of events throughout," Moran said. "The only difference is these are slightly bigger."

Several earthquakes of low- to mid-3 magnitude have punctuated the regular drumbeat of tiny earthquakes that have occurred every few minutes for the past several months.

Scientists are focused on two potential causes: Each quake either represents a lurch or surge of the massive spine coming out of the conduit, or it could represent fracturing of rock around the conduit pumping lava onto the crater surface. A third scenario raises the possibility of a slump or fracture within the lava dome after lava is extruded.

The volcano continues to extrude lava at a rate of about a pickup truck load every few seconds.

Forecasters said snow was reported in the southern Johannesburg township of Soweto and the posh northern suburb of Sandton, as well as the nearby towns of Carletonville and Westonaria.

Johannesburg last had snow on September 11, 1981.

"Sleet has been recorded occasionally since then, but never snow," added climatologist Tracey Gill.

Bloemfontein, the capital of the central Free State province, got its first snow in 12 years, receiving 13 centimetres (5.2 inches).

Comparable widespread snow across the country had been recorded only twice in the past 20 years, in 1981 and 1988, said Rae.

Some welcomed the colder weather, however.

At the Tiffindell ski resort in the southern Drakensberg mountains of the Eastern Cape province, guests were elated.

"They are very excited," said the resort's chief snow-maker, Johan Smuts. "It is not every day that you get to see snow fall in Africa."

In warmer weather, Smuts oversees the manufacture of snow for the resort through a process involving water and air compression.

Tiffindell usually gets about five snowfalls a year, he said, but rarely 25 centimetres in one day, as on Tuesday.

The weather service posted a warning on its website of very cold temperatures for the southeastern high elevations of the country into Thursday.

It expected snowfalls to continue over areas of the central Free State, the Drakensberg and the Eastern Cape, but to have passed by Friday.

In the northern provinces, the snow was expected to clear by Wednesday afternoon, said Rae.