Philadelphia public schools are closing early due to heat.
Before noon, the mercury had reached 90 degrees at Philadelphia International Airport, and the National Weather Service is calling for a high of 94.
The school district said schools with graduation ceremonies scheduled for today have the option to remain open for the graduation. Parents should contact the schools directly, the district said.
The closures come as scorching summer temperatures are arriving in the region a few days early.
The season officially begins Saturday, but the temperature in Philadelphia on Tuesday soared above 90 degrees for the first time this year, and the mercury will likely reach an even higher point today, forecasters say.
Tuesday saw a high of 93 degrees at the airport, the first time the mercury surpassed 90 since Sept. 11, which had a high of 94.
The weather service has issued a heat advisory for the region, in effect from noon to 7 p.m. Heat index values will reach the mid-to-upper 90s.
"The heat and humidity will create a hazard for anyone spending time out of doors today, especially those taking part in strenuous outdoor work or athletic activities," the advisory says.
Authorities say people should drink plenty of fluids, stay in conditioned places, avoid the sun, wear light-weight and loose-fitting clothing and check on neighbors, especially the elderly.
The record high for June 18 in Philadelphia is 96 degrees, set in 1957.
There's a chance of thunderstorms late tonight, most likely after 10 p.m., the weather service said.
Thursday is expected to remain hot, but slightly cooler than Tuesday and today, with a forecasted high of 89 degrees.