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Mercersburg, Pennsylvania

Borough in Franklin County, Pennsylvania

Air quality

The air at Mercersburg

Index 20, good, led by fine particles. Read at 11 PM from its reporting area, Hagerstown Region (MD), 15 miles off.

20Good
  • Fine particles (PM2.5)20Good20.6 mi
  • Ozone16Good15 ppb20.6 mi

The days ahead

Good each day through Sun Oct 18, led by fine particles. Yesterday measured 42, good.

Smoke, the next 46 hours

Little smoke near the ground through Sat 8 PM: the index from smoke stays at 6 or under.

FriSat

Precipitation

What has fallen at Mercersburg

0.08 in in the last 24 hours, 0.18 in over the last 3 days, to Thu 10 PM. Measured by radar and rain gauges, as water.

Last 24 hours
0.08in
Last 3 days
0.18in

Visibility

How far you can see at Mercersburg, the next 46 hours

Fog: visibility falls to 0.9 miles Fri 5 PM, under a mile for 1 hour.

FriSat

On the radar over Mercersburg, PennsylvaniaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 5 instruments nearest Mercersburg, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 9.6 miles away.

measured now3 instruments

measured daily2 instruments

Greencastle 0.3 SPA-FN-18

In a volunteer observer's own ground/9.9 mi away/607 ft/42 ft above here

precip, snowfall, snow depth

Rank-

Chambersburg 1 ESECHMP1

At a cooperative observer's station/15.9 mi away/643 ft/78 ft above here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Liberty - Raven Rock, drawn

The nearest airport reporting now, 26.1 mi from Mercersburg, Pennsylvania. From its report of Oct 15, 2026, 10:55 PM local time: 3 of its 6 sheets.

The sky

Overcast at 700 ft; the ceiling is 700 ft; visibility 6 mi.

Section of the sky over Liberty - Raven Rock, height above the station to scale: overcast cloud with its base at 700 feet, the ceiling at 700 feet, and visibility of 6 mi.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT XIFFIG. A THE SKY OVER LIBERTY - RAVEN ROCKSECTION, HEIGHT ABOVE THE STATION TO SCALE, EACH LAYER AT THE HEIGHT OF ITS BASE AS REPORTED; COVER IN EIGHTHS OF THE SKY; TOPS NOT MEASUREDFT ABOVE THE STATION05001,0001,5002,0002,5003,000ETAGESLOWTHE STATIONTHE CEILOMETER READS TO 12,000 FT, ABOVE THIS SHEETOVC 700 FTOVERCAST, 8 EIGHTHS OF THE SKYCEILING 700 FTVISIBILITY, MILES: 6 MI0510TITLELiberty - Raven Rock, the skySTATION REPORT · ASOS XIFTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-XIF-1DRAWN AS linework on paperSOURCES FB-SKY-001, FB-SKY-017, FB-SKY-016, FB-SKY-018

The air

57.0 F with a dew point of 56.0 F, 96 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 200 ft up; the lowest cloud reported is at 700 ft.

Chart of the air at Liberty - Raven Rock: temperature 57.0 degrees Fahrenheit and dew point 56.0, 96 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 200 feet above the station, against the lowest cloud reported at 700 feet; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT XIFFIG. B THE AIR AT LIBERTY - RAVEN ROCKTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00040 F50 F60 F70 FSATURATES 200 FT ABOVE THE STATION, AT 55.7 FLOWEST CLOUD REPORTED, OVC 700 FTTEMPERATURE AND DEW POINT 57.0 F, 56.0 FRELATIVE HUMIDITY 96 PER CENTTHE AIR COOLS ABOUT 5.4 F EACH 1,000 FT IT RISES, AND ITS DEW POINT ABOUT 1 FSOLID: THE LIFTED AIR'S TEMPERATURE; DASHED: ITS DEW POINTTITLELiberty - Raven Rock, the airSTATION REPORT · ASOS XIFTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-XIF-2DRAWN AS linework on paperSOURCES FB-WAT-020, FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

Calm.

Plan of the wind at Liberty - Raven Rock, north up: calm; beside it the Beaufort scale from calm to hurricane force, force 0, calm, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT XIFFIG. C THE WIND AT LIBERTY - RAVEN ROCKPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONCALMBEAUFORT FORCELEAST WIND, MPH0CALM0NOW, 0 MPH1LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLELiberty - Raven Rock, the windSTATION REPORT · ASOS XIFTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-XIF-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Liberty - Raven Rock, in 6 sheets, each beside the Field Book plates that explain it

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Snow on the ground

Elsewhere in Pennsylvania

24 places, each with its own forecast and its own instruments.

Near Mercersburg

The nearest places, each with its own forecast and the instruments nearest it.

Near Mercersburg

River and lake gauges