Ashland, Montana · field elev 2,909 ft
Density Altitude at St Labre Mission (3U4)
From a field elevation of 2,909 ft, a typical July afternoon at St Labre Mission (90 °F) raises density altitude to about 5,511 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 | 22.9 | 1,179 ft | 35.2 | 2,029 ft |
| February | 26.3 | 1,416 ft | 38.8 | 2,273 ft |
| March | 36.4 | 2,110 ft | 50.2 | 3,031 ft |
| April | 45.6 | 2,728 ft | 60.0 | 3,667 ft |
| May | 55.1 | 3,351 ft | 69.5 | 4,268 ft |
| June | 64.4 | 3,947 ft | 79.3 | 4,876 ft |
| July | 72.4 | 4,450 ft | 89.8 | 5,511 ft ▲ |
| August | 70.8 | 4,350 ft | 89.1 | 5,469 ft ▲ |
| September | 60.3 | 3,686 ft | 77.2 | 4,747 ft |
| October | 46.7 | 2,801 ft | 61.0 | 3,731 ft |
| November | 33.9 | 1,940 ft | 46.5 | 2,787 ft |
| December | 24.2 | 1,270 ft | 36.0 | 2,083 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 3U4
DENSITY ALTITUDE caution
Field elevation 2,909 ft — the air behaves like 5,523 ft.
- PRESSURE ALT
- 2,911 ft
- ISA DEVIATION
- —
- RULE-OF-THUMB DA
- —
- AIR DENSITY INDEX
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- 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
- 1M6 — Stevens Ranch
Ashland · elev 3,300 ft
- M46 — Colstrip
Colstrip · elev 3,428 ft
- 00F — Broadus
Broadus · elev 3,282 ft
- 1S3 — Tillitt Field
Forsyth · elev 2,729 ft
- KMLS — Frank Wiley Field
Miles City · elev 2,634 ft
- 6U7 — Hysham
Hysham · elev 2,624 ft
- 00U — Big Horn County
Hardin · elev 3,025 ft
- 5U7 — Fort Smith Landing Strip
Fort Smith · elev 3,242 ft
Frequently asked questions
How high does density altitude get at 3U4 in summer?
On a typical July afternoon — around 90 °F at the nearest NOAA normals station — density altitude at St Labre Mission reaches roughly 5,511 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 3U4 on an average day?
It swings with the seasons: from roughly 1,179 ft at the coldest month's average temperature to about 4,450 ft at the warmest month's — all from a constant field elevation of 2,909 ft. The month-by-month table above carries the full year.
What is the field elevation of St Labre Mission?
2,909 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 3U4 (FAA), in Ashland, Montana.