Jasper, Tennessee · field elev 641 ft
Density Altitude at Marion County/Brown Field (KAPT)
Marion County/Brown Field sits at 641 ft, and even a typical July afternoon (88 °F) only lifts density altitude to about 2,627 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 | 38.8 | −546 ft | 48.4 | 106 ft |
| February | 42.6 | −286 ft | 53.0 | 414 ft |
| March | 50.4 | 240 ft | 62.1 | 1,012 ft |
| April | 58.7 | 790 ft | 71.3 | 1,603 ft |
| May | 67.0 | 1,328 ft | 78.2 | 2,039 ft |
| June | 74.2 | 1,787 ft | 84.8 | 2,449 ft |
| July | 77.6 | 2,001 ft | 87.7 | 2,627 ft |
| August | 76.8 | 1,951 ft | 87.2 | 2,597 ft |
| September | 71.2 | 1,597 ft | 82.1 | 2,282 ft |
| October | 59.7 | 855 ft | 71.6 | 1,623 ft |
| November | 49.0 | 147 ft | 60.2 | 888 ft |
| December | 41.5 | −361 ft | 51.3 | 300 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 KAPT
DENSITY ALTITUDE
Field elevation 641 ft — the air behaves like 2,646 ft.
- PRESSURE ALT
- 642 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 Tennessee fields
- KUOS — Franklin County
Sewanee · elev 1,953 ft
- KCHA — Lovell Field
Chattanooga · elev 683 ft
- KBGF — Winchester Municipal
Winchester · elev 979 ft
- KFGU — Collegedale Municipal
Collegedale · elev 860 ft
- KTHA — Tullahoma Regional/Wm Northern Field
Tullahoma · elev 1,084 ft
- KRZR — Cleveland Regional Jetport
Cleveland · elev 866 ft
- KRNC — Warren County Meml
Mc Minnville · elev 1,032 ft
- 2A0 — Mark Anton
Dayton · elev 718 ft
Frequently asked questions
How high does density altitude get at KAPT in summer?
On a typical July afternoon — around 88 °F at the nearest NOAA normals station — density altitude at Marion County/Brown Field reaches roughly 2,627 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 KAPT on an average day?
It swings with the seasons: from roughly −546 ft at the coldest month's average temperature to about 2,001 ft at the warmest month's — all from a constant field elevation of 641 ft. The month-by-month table above carries the full year.
What is the field elevation of Marion County/Brown Field?
641 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KAPT (ICAO) / APT (FAA), in Jasper, Tennessee.