Chinook, Montana · field elev 2,416 ft
Density Altitude at Edgar G Obie (S71)
Edgar G Obie sits at 2,416 ft, and even a typical July afternoon (84 °F) only lifts density altitude to about 4,581 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 | 15.7 | 49 ft | 27.1 | 857 ft |
| February | 19.2 | 300 ft | 31.4 | 1,155 ft |
| March | 30.4 | 1,086 ft | 43.0 | 1,944 ft |
| April | 43.1 | 1,951 ft | 56.9 | 2,860 ft |
| May | 53.5 | 2,639 ft | 67.0 | 3,507 ft |
| June | 62.4 | 3,215 ft | 75.4 | 4,034 ft |
| July | 69.0 | 3,634 ft | 84.3 | 4,581 ft |
| August | 67.5 | 3,539 ft | 83.3 | 4,520 ft |
| September | 56.8 | 2,854 ft | 72.3 | 3,841 ft |
| October | 42.7 | 1,924 ft | 56.9 | 2,860 ft |
| November | 29.2 | 1,003 ft | 41.3 | 1,830 ft |
| December | 19.0 | 286 ft | 30.5 | 1,093 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 S71
DENSITY ALTITUDE
Field elevation 2,416 ft — the air behaves like 4,562 ft.
- PRESSURE ALT
- 2,417 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
- 48S — Harlem
Harlem · elev 2,643 ft
- KHVR — Havre City-County
Havre · elev 2,591 ft
- 6U6 — Hogeland
Hogeland · elev 3,139 ft
- 9U0 — Turner
Turner · elev 3,051 ft
- CW0 — Cow Creek
Winifred · elev 3,300 ft
- 3U8 — Big Sandy
Big Sandy · elev 2,699 ft
- LC0 — Left Coulee
Winifred · elev 3,150 ft
- BB0 — Black Butte North
Winifred · elev 3,150 ft
Frequently asked questions
How high does density altitude get at S71 in summer?
On a typical July afternoon — around 84 °F at the nearest NOAA normals station — density altitude at Edgar G Obie reaches roughly 4,581 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 S71 on an average day?
It swings with the seasons: from roughly 49 ft at the coldest month's average temperature to about 3,634 ft at the warmest month's — all from a constant field elevation of 2,416 ft. The month-by-month table above carries the full year.
What is the field elevation of Edgar G Obie?
2,416 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is S71 (FAA), in Chinook, Montana.