Pennsylvania, 2026

Dense Fog in Pennsylvania, March 20 to 21, 2026

March 20 to 21, 2026 · NWS PHI · 3 events in 3 counties and zones

A warm moist air advancing northward over cold ground helped cause widespread fog to form late on March 11th and early on March 12th. The fog dissipated near dawn.

Where it happened

Every event with a place to put it; 3 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
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
3

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 warm moist air advancing northward over cold ground helped cause widespread fog to form late on March 11th and early on March 12th. The fog dissipated near dawn.

The radar

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

Open the radar archive at this moment

Event by event

3 dense fog. Local standard time, as filed.

Dense Fog, Berks

When
March 20, 11:00 PM EST to March 21, 8:00 AM EST
Where
Berks forecast zone
Reported by
ASOS
Coordinates
40.416, -75.926 (the zone’s center; the record gives no point)

Several hours of dense fog was observed at Reading Regional Airport.

Dense Fog, Upper Bucks

When
March 20, 11:00 PM EST to March 21, 8:00 AM EST
Where
Upper Bucks forecast zone
Reported by
AWOS
Coordinates
40.337, -75.107 (the zone’s center; the record gives no point)

Several hours of dense fog was observed at Pennridge Airport.

Dense Fog, Western Montgomery

When
March 20, 11:00 PM EST to March 21, 8:00 AM EST
Where
Western Montgomery forecast zone
Reported by
ASOS
Coordinates
40.211, -75.367 (the zone’s center; the record gives no point)

Several hours of dense fog was observed at Heritage Field.

What these are

Dense Fog
Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.

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

The same day elsewhere

More

Every storm in Pennsylvania in 2026Every state in 2026This day in weather historyWarnings in Pennsylvania, March 2026

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 2026-10-01. Each event’s entry at NCEI: 1321729, 1321730, 1321731.