Delicate flowers and beefy construction workers wilted, brows sprouted beads of sweat and schools closed early as a layer of hot, sticky air settled over the Baltimore area yesterday.
By 4 p.m. the temperature at Baltimore's Inner Harbor had climbed to a high of 93 degrees, with a heat index - a measurement that combines heat and humidity to reflect how hot it feels - of 94. The official high at Baltimore-Washington International Airport was 91. The heat index there reached 96.
In some places, it felt much, much hotter.
"Up there, you're chicken on tinfoil," said Steve Martin, an Overlea ironworker, gesturing to the four-story network of steel that he and his co-workers from Baltimore Steel Erectors were constructing at Towson University's new football stadium.
Weather forecasters say temperatures should reach the 90s again today but begin cooling by tomorrow.
By mid-afternoon yesterday, virtually all of Central Maryland and the Eastern Shore was blanketed with moderately unhealthy levels of smog, which is formed when pollutants literally cook in hot, still air.
Pollution was worst in Harford and Cecil counties, where readings of ground level ozone, the main ingredient in smog, hit the "code red" level in late afternoon. Light breezes kept ozone at "code orange" levels from Charles County to the Pennsylvania line.
Unlike code red ozone levels, which are unhealthy for everyone, code orange conditions cause breathing difficulties for children, the elderly and anyone with chronic respiratory problems.
People in those groups are advised to stay indoors today, with the forecast calling for more code orange pollution.
Schools close early
Baltimore City schools - most of which have no air conditioning - closed 2 1/2 hours early yesterday. The school system dismisses its 93,000 students early if the temperature reaches - or is expected to reach - 90 degrees by 11 a.m. City schools close for the year Monday.
Four Baltimore County public schools - Franklin High in Reisterstown, Glyndon Elementary in Glyndon, Deer Park Magnet Middle School in Owings Mills and Woodbridge Elementary in Woodlawn - closed early because of faulty air conditioning.
Baltimore County public schools will close three hours early today with the heat and humidity expected to continue. Friday is the last day of school.
Yesterday's temperature, though higher than the normal high of 82 for a June day, didn't break any records. The hottest June 11 in Baltimore was in 1911, when temperatures reached 99 degrees. The hottest June day ever recorded in the city was June 29, 1934, when it was a sweltering 105 degrees.
National Weather Service records show that BWI averages 30 days per summer of 90-degree or above temperatures.
While today will be hot, a cold front will approach from the west tonight, bringing showers and thunderstorms and temperatures in the low to mid-80s for tomorrow, according to Julie Arthur, a meteorologist with the NWS in Sterling, Va.
Chris Johannesson, a meteorologist at Penn State Weather Communications Group, said that temperatures will be in the 70s and 80s over the weekend. "Once the [cold] front makes it through, the air will be noticeably different, less humid," he said.
However, the prospect of cooler temperatures did little to help some cope with yesterday's heat.
At Annapolis' City Dock, tour guides dressed in Colonial-era costumes said this time of year is particularly trying.
Robert Clemens, 71, and Lew Billups, 70, with Three Centuries tours, relaxed on a bench in the shade between tours yesterday, dressed in knickers with long stockings, long-sleeved cotton shirts and three-cornered hats.
"The stockings are a little warm on a day like today," Clemens said. "It's warm, but we do our tours anyway. When you take a group around, you seek out the shade."
Outside a Giant supermarket in Howard County, Kevin Wright, a construction worker cementing a sidewalk, knew he was anything but an object of envy.
"Everyone feels sorry for us today," said Wright, 30, of Greenbelt, whose white T-shirt was soaked through with perspiration.
Cool with books
In Carroll County, libraries felt the press of adults seeking relief from the heat and students who finished public school last week.
"Some days it's too hot to be at the pool, the humidity is so uncomfortable, so they come here," said Westminster librarian Brenda L. Conaway.
Steve Sarro, curator of birds and mammals at the Baltimore Zoo, said the zoo has taken precautions to protect the animals from the heat.
Polar bears, the most susceptible to heat stress, were provided fish-filled icicles and pool access. Penguins frolicked under sprinklers while monkeys enjoyed frozen Gatorade treats.
"The animals find solutions," Sarro said. "They'll lie under a shady tree or lie in the pool. They're all quite content, actually."
Water and sunscreen
City Health Commissioner Peter L. Beilenson recommended that people drink lots of water and wear sunscreen. He also said yesterday's temperatures present no cause for alarm.
"The bottom line is, this is a typical Baltimore summer day," Beilenson said.
He recommended that senior citizens without air conditioning go to senior centers to keep cool.
At North Arundel Hospital, the emergency room was prepared for a wave of heat-related admissions - later in the week.
"We usually don't see many people on the first hot day," said Kevin Murnane, a hospital spokesman, who noted that by 3:30 p.m. yesterday there had been no admissions for heat stroke or dehydration.
"It's the cumulative affect of the hot weather that really causes problems."
Sun staff writers Laura Barnhardt, Ellie Baublitz, Athima Chansanchai, Amanda J. Crawford, Heather Dewar, Josh Mitchell, Erika Niedwoski, Jay Parsons, Frank D. Roylance and Jason Song contributed to this article.