Johnstown, Pennsylvania · field elev 2,284 ft
Density Altitude at John Murtha Johnstown/Cambria County (KJST)
John Murtha Johnstown/Cambria County sits at 2,284 ft, and even a typical July afternoon (79 °F) only lifts density altitude to about 4,071 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 | 26.3 | 636 ft | 33.4 | 1,128 ft |
| February | 28.7 | 803 ft | 36.3 | 1,327 ft |
| March | 36.4 | 1,334 ft | 44.7 | 1,894 ft |
| April | 48.1 | 2,121 ft | 57.9 | 2,763 ft |
| May | 58.5 | 2,801 ft | 68.2 | 3,421 ft |
| June | 66.0 | 3,282 ft | 74.9 | 3,842 ft |
| July | 69.9 | 3,529 ft | 78.6 | 4,071 ft |
| August | 68.6 | 3,447 ft | 77.1 | 3,978 ft |
| September | 61.6 | 3,001 ft | 70.5 | 3,566 ft |
| October | 51.1 | 2,319 ft | 59.4 | 2,860 ft |
| November | 40.1 | 1,585 ft | 47.4 | 2,074 ft |
| December | 31.2 | 977 ft | 37.8 | 1,429 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 KJST
DENSITY ALTITUDE
Field elevation 2,284 ft — the air behaves like 4,095 ft.
- PRESSURE ALT
- 2,285 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
- 9G8 — Ebensburg
Ebensburg · elev 2,099 ft
- 2G9 — Somerset County
Somerset · elev 2,275 ft
- KHMZ — Bedford County
Bedford · elev 1,162 ft
- KIDI — Indiana County/Jimmy Stewart Field
Indiana · elev 1,419 ft
- KAOO — Altoona/Blair County
Altoona · elev 1,503 ft
- KLBE — Arnold Palmer Regional
Latrobe · elev 1,199 ft
- 6G6 — Cove Valley
Williamsburg · elev 1,156 ft
- P45 — Mount Pleasant/Scottdale
Mount Pleasant · elev 1,160 ft
Frequently asked questions
How high does density altitude get at KJST in summer?
On a typical July afternoon — around 79 °F at the nearest NOAA normals station — density altitude at John Murtha Johnstown/Cambria County reaches roughly 4,071 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 KJST on an average day?
It swings with the seasons: from roughly 636 ft at the coldest month's average temperature to about 3,529 ft at the warmest month's — all from a constant field elevation of 2,284 ft. The month-by-month table above carries the full year.
What is the field elevation of John Murtha Johnstown/Cambria County?
2,284 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KJST (ICAO) / JST (FAA), in Johnstown, Pennsylvania.