Heat in Pennsylvania, June 7 to 9, 1999

Name: Heat in Pennsylvania, June 7 to 9, 1999
Start: 1999-06-07T09:00
End: 1999-06-09T18:00
Location: Pennsylvania

June 7 to 9, 1999 · NWS PHI · 8 events in 8 counties and zones

A large high pressure system over the southeastern United States pumped in a hot and humid air mass across most of Eastern Pennsylvania for three days. The hottest day was the 8th.

Where it happened

Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 2
Injuries: 1
Property damage: None recorded
Crop damage: None recorded
Events: 8

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS PHI wrote it up.

A large high pressure system over the southeastern United States pumped in a hot and humid air mass across most of Eastern Pennsylvania for three days. The hottest day was the 8th. A weak trough brought in slightly cooler and considerably drier air on the 9th, although high temperatures still reached around 90 degrees. A stronger backdoor cold front (it moved from north to south) brought in considerably cooler air into the region the evening of the 9th. There were two heat related deaths in Montgomery County. The high temperature of 95 degrees on the 8th at the Philadelphia International Airport established a new record high for the day and already matched the hottest day in the city for all of 1998. Two heat related deaths and at least one heat related injury occurred in Montgomery County. A 62-year-old man was found dead on the third floor of his apartment in Pottstown. An 85-year-old man collapsed in his garage in Royersford. In and around Philadelphia, many school districts that did not have air conditioning dismissed their children early or rotated classes through air conditioned sections of the school. Area health departments issued hot weather health warnings called "code red" to alert and assist the elderly. In Philadelphia search teams went looking for the homeless. In Delaware County fans were distributed to the elderly. PECO Energy reported the highest power usage of the year, about 40 percent above normal. The strain on electrical systems caused about 20,000 homes and businesses to lose power, more than half in Montgomery County after a power substation failed. Highest temperatures during this hot spell included 98 degrees at the Franklin Institute within Philadelphia, Springfield (Delaware County) and Green Lane (Montgomery County), 97 degrees in Hamburg (Berks County) and Easton (Northampton County), 96 degrees in Reading (Berks County) and Neshaminy Falls (Bucks County), 95 degrees at the Philadelphia International Airport, Pottstown (Montgomery County) and Doylestown (Bucks County), 94 degrees at the Lehigh Valley International Airport, the Willow Grove NAS (Montgomery County), Perkasie (Bucks County) and East Stroudsburg (Monroe County), 93 degrees at the Wilkes-Barre/Scranton International Airport (Luzerne County) and 91 degrees at both Mount Pocono (Monroe County) and the F. E. Walter Dam (Carbon County).

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

8 heat. Local standard time, as filed.

Heat, Berks

When: June 7, 9:00 AM EST to June 8, 6:00 PM EST
Where: Berks forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 40.416, -75.926 (the zone’s center; the record gives no point)

Heat, Lehigh

When: June 7, 9:00 AM EST to June 8, 6:00 PM EST
Where: Lehigh forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 40.613, -75.592 (the zone’s center; the record gives no point)

Heat, Northampton

When: June 7, 9:00 AM EST to June 8, 6:00 PM EST
Where: Northampton forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 40.754, -75.307 (the zone’s center; the record gives no point)

Heat, Bucks

When: June 7, 9:00 AM EST to June 8, 6:00 PM EST
Where: Bucks forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

Heat, Chester

When: June 7, 9:00 AM EST to June 8, 6:00 PM EST
Where: Chester forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

Heat, Delaware

When: June 7, 9:00 AM EST to June 9, 6:00 PM EST
Where: Delaware forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 39.917, -75.399 (the zone’s center; the record gives no point)

Heat, Montgomery

When: June 7, 9:00 AM EST to June 8, 6:00 PM EST
Where: Montgomery forecast zone
Deaths: 2 direct, 0 indirect
Injuries: 1 direct, 0 indirect
Reported by: AWOS,ASOS,MESONET,ETC

Heat, Philadelphia

When: June 7, 9:00 AM EST to June 9, 6:00 PM EST
Where: Philadelphia forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 40.008, -75.134 (the zone’s center; the record gives no point)

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Heat, Montgomery	1999-06-07	62	Male	Permanent Home	Direct
Heat, Montgomery	1999-06-08	85	Male	Permanent Home	Direct

What these are

Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Pennsylvania in 1999 Every state in 1999 This day in weather history Warnings in Pennsylvania, June 1999

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 5703504, 5703505, 5703506, 5703507, 5703508, 5703509, 5703510, 5703511.