Myerstown, Pennsylvania · field elev 523 ft
Density Altitude at Deck (9D4)
Deck sits at 523 ft, and even a typical July afternoon (84 °F) only lifts density altitude to about 2,281 ft — heat still trims performance, but the field rarely turns high-and-hot.
Typical density altitude by month
| Month | Avg temp °F | DA at avg temp | Afternoon high °F | DA on a typical afternoon |
|---|---|---|---|---|
| January | 29.5 | −1,341 ft | 37.0 | −818 ft |
| February | 31.9 | −1,173 ft | 40.4 | −583 ft |
| March | 40.1 | −604 ft | 49.4 | 27 ft |
| April | 51.1 | 141 ft | 62.0 | 860 ft |
| May | 61.2 | 808 ft | 71.9 | 1,497 ft |
| June | 69.9 | 1,369 ft | 80.0 | 2,007 ft |
| July | 74.3 | 1,649 ft | 84.4 | 2,281 ft |
| August | 72.5 | 1,535 ft | 82.4 | 2,157 ft |
| September | 65.5 | 1,087 ft | 75.6 | 1,731 ft |
| October | 54.0 | 334 ft | 64.1 | 996 ft |
| November | 43.2 | −392 ft | 52.3 | 221 ft |
| December | 34.3 | −1,005 ft | 41.7 | −494 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 9D4
DENSITY ALTITUDE
Field elevation 523 ft — the air behaves like 2,256 ft.
- PRESSURE ALT
- 524 ft
- ISA DEVIATION
- —
- RULE-OF-THUMB DA
- —
- AIR DENSITY INDEX
- —
- AIR DENSITY
- —
- WATER · GRAINS/LB
- —
For training and reference · verify with official sources and your POH before flight · no tool on this site renders a go / no-go judgment
Nearby Pennsylvania fields
- 08N — Keller Brothers
Lebanon · elev 550 ft
- 9N7 — Farmers Pride
Fredericksburg · elev 495 ft
- 8N1 — Grimes
Bethel · elev 582 ft
- 58N — Reigle Field
Palmyra · elev 489 ft
- KLNS — Lancaster
Lancaster · elev 403 ft
- 74N — Bendigo
Tower City · elev 791 ft
- KRDG — Reading Regional/Carl A Spaatz Field
Reading · elev 343 ft
- N71 — Donegal Springs Airpark
Mount Joy/Marietta · elev 458 ft
Frequently asked questions
How high does density altitude get at 9D4 in summer?
On a typical July afternoon — around 84 °F at the nearest NOAA normals station — density altitude at Deck reaches roughly 2,281 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 9D4 on an average day?
It swings with the seasons: from roughly −1,341 ft at the coldest month's average temperature to about 1,649 ft at the warmest month's — all from a constant field elevation of 523 ft. The month-by-month table above carries the full year.
What is the field elevation of Deck?
523 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 9D4 (FAA), in Myerstown, Pennsylvania.