Big Sandy, Montana · field elev 2,699 ft
Density Altitude at Big Sandy (3U8)
From a field elevation of 2,699 ft, a typical July afternoon at Big Sandy (86 °F) raises density altitude to about 5,022 ft — solidly into the range where performance charts deserve a close read.
Typical density altitude by month
| Month | Avg temp °F | DA at avg temp | Afternoon high °F | DA on a typical afternoon |
|---|---|---|---|---|
| January | 20.3 | 732 ft | 30.8 | 1,466 ft |
| February | 24.3 | 1,014 ft | 35.2 | 1,768 ft |
| March | 34.0 | 1,686 ft | 46.0 | 2,494 ft |
| April | 45.5 | 2,461 ft | 58.4 | 3,306 ft |
| May | 54.6 | 3,060 ft | 67.9 | 3,911 ft |
| June | 62.4 | 3,562 ft | 75.9 | 4,410 ft |
| July | 70.3 | 4,062 ft | 85.9 | 5,022 ft ▲ |
| August | 69.1 | 3,986 ft | 84.8 | 4,955 ft |
| September | 59.0 | 3,344 ft | 73.7 | 4,274 ft |
| October | 45.6 | 2,468 ft | 58.7 | 3,325 ft |
| November | 32.6 | 1,590 ft | 43.6 | 2,335 ft |
| December | 23.3 | 944 ft | 33.5 | 1,652 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 3U8
DENSITY ALTITUDE caution
Field elevation 2,699 ft — the air behaves like 5,028 ft.
- PRESSURE ALT
- 2,701 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
- KHVR — Havre City-County
Havre · elev 2,591 ft
- 79S — Fort Benton
Fort Benton · elev 2,869 ft
- 5U8 — Geraldine
Geraldine · elev 3,185 ft
- KLTY — Liberty County
Chester · elev 3,185 ft
- B70 — Tiber Dam
Tiber Dam · elev 3,023 ft
- BB0 — Black Butte North
Winifred · elev 3,150 ft
- S71 — Edgar G Obie
Chinook · elev 2,416 ft
- BW8 — Bullwhacker
Winifred · elev 3,100 ft
Frequently asked questions
How high does density altitude get at 3U8 in summer?
On a typical July afternoon — around 86 °F at the nearest NOAA normals station — density altitude at Big Sandy reaches roughly 5,022 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 3U8 on an average day?
It swings with the seasons: from roughly 732 ft at the coldest month's average temperature to about 4,062 ft at the warmest month's — all from a constant field elevation of 2,699 ft. The month-by-month table above carries the full year.
What is the field elevation of Big Sandy?
2,699 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 3U8 (FAA), in Big Sandy, Montana.