Greenville, Kentucky · field elev 428 ft

Density Altitude at Muhlenberg County (M21)

Muhlenberg County sits at 428 ft, and even a typical July afternoon (89 °F) only lifts density altitude to about 2,448 ft — heat still trims performance, but the field rarely turns high-and-hot.

worst typical month: July · ≈2,448 ft station: ROCHESTER FERRY · 14 mi away normals vintage 1991–2020

Typical density altitude by month

From NOAA 1991–2020 monthly normals at ROCHESTER FERRY (14 mi from the field) · standard pressure, dry air
Month Avg temp °F DA at avg temp Afternoon high °F DA on a typical afternoon
January 33.6 −1,172 ft 43.6 −483 ft
February 37.3 −915 ft 48.4 −158 ft
March 45.9 −327 ft 58.1 487 ft
April 56.0 349 ft 69.3 1,214 ft
May 65.2 950 ft 77.9 1,760 ft
June 73.3 1,469 ft 85.6 2,239 ft
July 77.1 1,709 ft 89.0 2,448 ft
August 75.5 1,608 ft 88.2 2,399 ft
September 68.7 1,176 ft 81.8 2,003 ft
October 57.0 415 ft 70.9 1,317 ft
November 45.6 −347 ft 57.7 461 ft
December 37.5 −901 ft 47.6 −212 ft

▲ above 5,000 ft · ⚠ above 8,000 ft. These are planning references at standard pressure and dry air — afternoon humidity and low pressure both push the real number higher. Run today's values below.

Run today’s numbers for M21

Altimeter-style gauge: field elevation and density altitude needles 03691215 DENSITY ALT ×1,000 FT 2,448 DENSITY ALTITUDE · FEET
field elevation density altitude

DENSITY ALTITUDE 2,448 ft

Field elevation 428 ft — the air behaves like 2,448 ft.

PRESSURE ALT
429 ft
ISA DEVIATION
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RULE-OF-THUMB DA
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AIR DENSITY INDEX
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AIR DENSITY
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WATER · GRAINS/LB
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For training and reference · verify with official sources and your POH before flight · no tool on this site renders a go / no-go judgment

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Frequently asked questions

How high does density altitude get at M21 in summer?

On a typical July afternoon — around 89 °F at the nearest NOAA normals station — density altitude at Muhlenberg County reaches roughly 2,448 ft at standard pressure. Hotter-than-normal days, low pressure, and humidity all push it higher, so run the day's actual numbers before flying.

What is the density altitude at M21 on an average day?

It swings with the seasons: from roughly −1,172 ft at the coldest month's average temperature to about 1,709 ft at the warmest month's — all from a constant field elevation of 428 ft. The month-by-month table above carries the full year.

What is the field elevation of Muhlenberg County?

428 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is M21 (FAA), in Greenville, Kentucky.