Ennis, Montana · field elev 5,433 ft
Density Altitude at Ennis Big Sky (KEKS)
Ennis Big Sky is a genuine high-and-hot field: from 5,433 ft of elevation, a typical July afternoon (83 °F) pushes density altitude to about 8,153 ft — the airplane performs like it is 2,720 ft above the field before the wheels roll.
Typical density altitude by month
| Month | Avg temp °F | DA at avg temp | Afternoon high °F | DA on a typical afternoon |
|---|---|---|---|---|
| January | 24.6 | 4,444 ft | 34.0 | 5,079 ft ▲ |
| February | 26.2 | 4,553 ft | 37.1 | 5,285 ft ▲ |
| March | 34.0 | 5,079 ft | 46.4 | 5,895 ft ▲ |
| April | 41.1 | 5,549 ft | 54.6 | 6,420 ft ▲ |
| May | 49.4 | 6,088 ft | 64.1 | 7,017 ft ▲ |
| June | 56.7 | 6,553 ft | 72.6 | 7,539 ft ▲ |
| July | 64.2 | 7,023 ft | 82.8 | 8,153 ft ⚠ |
| August | 62.8 | 6,936 ft | 82.1 | 8,111 ft ⚠ |
| September | 54.6 | 6,420 ft | 72.2 | 7,515 ft ▲ |
| October | 43.3 | 5,693 ft | 57.6 | 6,610 ft ▲ |
| November | 32.1 | 4,952 ft | 42.7 | 5,654 ft ▲ |
| December | 23.8 | 4,389 ft | 33.2 | 5,026 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 KEKS
DENSITY ALTITUDE high DA
Field elevation 5,433 ft — the air behaves like 8,165 ft.
- PRESSURE ALT
- 5,435 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 Montana fields
- KRVF — Ruby Valley Field
Twin Bridges · elev 4,789 ft
- 9S5 — Three Forks
Three Forks · elev 4,089 ft
- KBZN — Bozeman Yellowstone International
Bozeman · elev 4,473 ft
- KDLN — Dillon
Dillon · elev 5,245 ft
- 29S — Gardiner
Gardiner · elev 5,286 ft
- KWYS — Yellowstone
West Yellowstone · elev 6,649 ft
- KBTM — Bert Mooney
Butte · elev 5,551 ft
- 4U9 — Dell Flight Strip
Dell · elev 6,007 ft
Frequently asked questions
How high does density altitude get at KEKS in summer?
On a typical July afternoon — around 83 °F at the nearest NOAA normals station — density altitude at Ennis Big Sky reaches roughly 8,153 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 KEKS on an average day?
It swings with the seasons: from roughly 4,389 ft at the coldest month's average temperature to about 7,023 ft at the warmest month's — all from a constant field elevation of 5,433 ft. The month-by-month table above carries the full year.
What is the field elevation of Ennis Big Sky?
5,433 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KEKS (ICAO) / EKS (FAA), in Ennis, Montana.