Twin Bridges, Montana · field elev 4,789 ft
Density Altitude at Ruby Valley Field (KRVF)
From a field elevation of 4,789 ft, a typical July afternoon at Ruby Valley Field (85 °F) raises density altitude to about 7,486 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 | 24.2 | 3,615 ft | 35.4 | 4,375 ft |
| February | 27.3 | 3,827 ft | 39.6 | 4,655 ft |
| March | 35.5 | 4,382 ft | 49.2 | 5,283 ft ▲ |
| April | 42.5 | 4,846 ft | 57.0 | 5,783 ft ▲ |
| May | 51.3 | 5,419 ft | 66.4 | 6,373 ft ▲ |
| June | 58.7 | 5,891 ft | 74.7 | 6,883 ft ▲ |
| July | 65.4 | 6,311 ft | 84.7 | 7,486 ft ▲ |
| August | 63.3 | 6,180 ft | 83.4 | 7,408 ft ▲ |
| September | 55.1 | 5,662 ft | 73.5 | 6,810 ft ▲ |
| October | 43.6 | 4,918 ft | 59.3 | 5,929 ft ▲ |
| November | 31.7 | 4,126 ft | 44.1 | 4,951 ft |
| December | 23.3 | 3,553 ft | 34.5 | 4,315 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 KRVF
DENSITY ALTITUDE caution
Field elevation 4,789 ft — the air behaves like 7,503 ft.
- PRESSURE ALT
- 4,791 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
- KDLN — Dillon
Dillon · elev 5,245 ft
- KBTM — Bert Mooney
Butte · elev 5,551 ft
- KEKS — Ennis Big Sky
Ennis · elev 5,433 ft
- 02T — Wise River
Wise River · elev 5,830 ft
- 9S5 — Three Forks
Three Forks · elev 4,089 ft
- 3U9 — Boulder
Boulder · elev 4,968 ft
- 3U3 — Bowman Field
Anaconda · elev 5,034 ft
- 7S4 — Wisdom
Wisdom · elev 6,133 ft
Frequently asked questions
How high does density altitude get at KRVF in summer?
On a typical July afternoon — around 85 °F at the nearest NOAA normals station — density altitude at Ruby Valley Field reaches roughly 7,486 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 KRVF on an average day?
It swings with the seasons: from roughly 3,553 ft at the coldest month's average temperature to about 6,311 ft at the warmest month's — all from a constant field elevation of 4,789 ft. The month-by-month table above carries the full year.
What is the field elevation of Ruby Valley Field?
4,789 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KRVF (ICAO) / RVF (FAA), in Twin Bridges, Montana.