Helena, Montana · field elev 3,877 ft
Density Altitude at Helena Regional (KHLN)
From a field elevation of 3,877 ft, a typical July afternoon at Helena Regional (86 °F) raises density altitude to about 6,464 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 | 23.0 | 2,395 ft | 32.4 | 3,041 ft |
| February | 27.2 | 2,685 ft | 37.2 | 3,366 ft |
| March | 36.1 | 3,292 ft | 47.5 | 4,049 ft |
| April | 44.5 | 3,851 ft | 56.7 | 4,644 ft |
| May | 53.9 | 4,464 ft | 66.4 | 5,258 ft ▲ |
| June | 61.7 | 4,963 ft | 74.7 | 5,773 ft ▲ |
| July | 70.6 | 5,520 ft | 86.1 | 6,464 ft ▲ |
| August | 68.8 | 5,408 ft | 84.6 | 6,374 ft ▲ |
| September | 58.9 | 4,785 ft | 73.3 | 5,687 ft ▲ |
| October | 45.5 | 3,917 ft | 57.6 | 4,702 ft |
| November | 32.8 | 3,068 ft | 42.8 | 3,739 ft |
| December | 23.4 | 2,423 ft | 32.6 | 3,055 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 KHLN
DENSITY ALTITUDE caution
Field elevation 3,877 ft — the air behaves like 6,458 ft.
- PRESSURE ALT
- 3,879 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
- 8U9 — Canyon Ferry
Townsend · elev 3,840 ft
- 3U9 — Boulder
Boulder · elev 4,968 ft
- 8U8 — Townsend
Townsend · elev 3,897 ft
- S69 — Lincoln
Lincoln · elev 4,603 ft
- 38S — Deer Lodge-City-County
Deer Lodge · elev 4,693 ft
- KBTM — Bert Mooney
Butte · elev 5,551 ft
- 7S6 — White Sulphur Springs
White Sulphur Springs · elev 5,065 ft
- 3U3 — Bowman Field
Anaconda · elev 5,034 ft
Frequently asked questions
How high does density altitude get at KHLN in summer?
On a typical July afternoon — around 86 °F at the nearest NOAA normals station — density altitude at Helena Regional reaches roughly 6,464 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 KHLN on an average day?
It swings with the seasons: from roughly 2,395 ft at the coldest month's average temperature to about 5,520 ft at the warmest month's — all from a constant field elevation of 3,877 ft. The month-by-month table above carries the full year.
What is the field elevation of Helena Regional?
3,877 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KHLN (ICAO) / HLN (FAA), in Helena, Montana.