Irwin, Pennsylvania · field elev 1,250 ft
Density Altitude at Inter County (31D)
Inter County sits at 1,250 ft, and even a typical July afternoon (83 °F) only lifts density altitude to about 3,081 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 | −432 ft | 36.6 | 61 ft |
| February | 32.1 | −251 ft | 39.9 | 287 ft |
| March | 40.4 | 321 ft | 49.4 | 928 ft |
| April | 52.1 | 1,107 ft | 62.5 | 1,788 ft |
| May | 61.8 | 1,742 ft | 71.9 | 2,388 ft |
| June | 69.5 | 2,236 ft | 79.1 | 2,840 ft |
| July | 73.6 | 2,495 ft | 83.0 | 3,081 ft |
| August | 72.1 | 2,401 ft | 81.3 | 2,976 ft |
| September | 65.4 | 1,974 ft | 74.8 | 2,571 ft |
| October | 54.2 | 1,246 ft | 63.3 | 1,839 ft |
| November | 43.2 | 511 ft | 51.1 | 1,041 ft |
| December | 34.4 | −91 ft | 41.0 | 362 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 31D
DENSITY ALTITUDE
Field elevation 1,250 ft — the air behaves like 3,081 ft.
- PRESSURE ALT
- 1,251 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
- KAGC — Allegheny County
Pittsburgh · elev 1,252 ft
- KFWQ — Rostraver
Monongahela · elev 1,228 ft
- 5G8 — Greensburg Jeannette Regional
Jeannette · elev 1,188 ft
- G05 — Finleyville Airpark
Finleyville · elev 1,236 ft
- KLBE — Arnold Palmer Regional
Latrobe · elev 1,199 ft
- P45 — Mount Pleasant/Scottdale
Mount Pleasant · elev 1,160 ft
- 22D — Bandel
Eighty Four · elev 1,210 ft
- KPIT — Pittsburgh International
Pittsburgh · elev 1,203 ft
Frequently asked questions
How high does density altitude get at 31D in summer?
On a typical July afternoon — around 83 °F at the nearest NOAA normals station — density altitude at Inter County reaches roughly 3,081 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 31D on an average day?
It swings with the seasons: from roughly −432 ft at the coldest month's average temperature to about 2,495 ft at the warmest month's — all from a constant field elevation of 1,250 ft. The month-by-month table above carries the full year.
What is the field elevation of Inter County?
1,250 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 31D (FAA), in Irwin, Pennsylvania.