Another heat wave clamped down on much of the East on Saturday, with temperatures in the high 90s and 100s, and residents scrambling for shade or just staying indoors.

TOMS RIVER, N.J. — Another heat wave clamped down on much of the East on Saturday, with temperatures in the high 90s and 100s, and residents scrambling for shade or just staying indoors.

In the Mid-Atlantic, already the locus for high temperatures several times in July, weather experts warned of dangerous conditions and residents resigned themselves to coping with the discomfort.

“Oh, it’s disgusting. It’s already really hot,” meteorologist Heather Sheffield of the National Weather Service said of morning temperatures in Washington, D.C.

One possible weather-related death was reported in Maryland, where paramedics said the high temperatures and humidity likely played a role in the death of a 20-year-old man who was biking, went into cardiac arrest and hit his head on a tree as he fell.

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With the heat and humidity combining for a possible heat index of more than 110 degrees, the weather service issued an excessive-heat warning for the first time this year for an area stretching from south of Washington, D.C., to north of Baltimore, along the Interstate 95 corridor. By midday Saturday, a wide band from lower New England to the Deep South was under a heat advisory.

The thermometer hit 100 degrees in Washington, D.C., and Baltimore by midafternoon, where the heat index was 109. In Norfolk, Va., it was 104 degrees and 108 degrees with the heat index. Elsewhere, record highs for July 24 of 97 degrees in New York and Philadelphia and 99 degrees in Newark, N.J., were reported.

As temperatures soared toward 100 in New Jersey, Harry Oliver, 47, contemplated an irony as he waited to get sandwiches at a Toms River convenience store.

“When I complain about the heat and humidity, my wife reminds me that I was begging for this type of weather when I was shoveling all that snow this past winter,” he said. “Now I’m looking forward to the snow again.”

Kristin Kline, a weather-service meteorologist in Mount Holly, N.J., said this summer hasn’t been “record-setting hot” in most places. The off-and-on scorching heat that’s been felt in the Mid-Atlantic can be blamed on “a Bermuda high” between Bermuda and North Carolina that is pushing hot, humid air into the region, Kline said.

It is not that any one day has set a heat record, but a large area of the country has been assaulted by a succession of heat waves. Washington, D.C., in June recorded the highest average temperature for the month since record keeping began in 1871, including 18 days of 90 degrees or more. July is on its way to a similar record.

In New York City, temperatures in July have averaged 5.5 degrees above normal, according to the private weather service AccuWeather.

The stifling heat this summer seems to be part of a global trend. So far, 2010 is on track to overtake 2005 as the warmest year recorded for the planet, according to the National Oceanic and Atmospheric Administration.

In Germany, a French fry crisis is looming: The length of fries may decline by nearly half an inch because heat and drought have cut the harvest of larger potatoes, Reuters reported.

But even the endless summer of 2010 cannot compare to the hottest year of all, said Stephen Fybish, a weather historian in New York. In a class by itself, he said, was the Dust Bowl summer of 1936, when 15 states set records for heat that stand to this day.

Material from The New York Times is included in this report.