Ruth, California · field elev 2,781 ft
Density Altitude at Ruth (T42)
From a field elevation of 2,781 ft, a typical July afternoon at Ruth (95 °F) raises density altitude to about 5,671 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 | 40.3 | 2,215 ft | 49.5 | 2,827 ft |
| February | 43.3 | 2,416 ft | 55.3 | 3,206 ft |
| March | 47.2 | 2,675 ft | 61.1 | 3,580 ft |
| April | 51.8 | 2,978 ft | 67.6 | 3,992 ft |
| May | 59.4 | 3,471 ft | 77.1 | 4,584 ft |
| June | 66.3 | 3,910 ft | 86.1 | 5,133 ft ▲ |
| July | 73.7 | 4,374 ft | 95.1 | 5,671 ft ▲ |
| August | 72.3 | 4,287 ft | 94.5 | 5,636 ft ▲ |
| September | 66.2 | 3,904 ft | 88.5 | 5,278 ft ▲ |
| October | 55.8 | 3,238 ft | 75.2 | 4,467 ft |
| November | 45.4 | 2,556 ft | 57.3 | 3,335 ft |
| December | 38.6 | 2,100 ft | 46.7 | 2,642 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 T42
DENSITY ALTITUDE caution
Field elevation 2,781 ft — the air behaves like 5,666 ft.
- PRESSURE ALT
- 2,783 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 California fields
- F62 — Hayfork
Hayfork · elev 2,334 ft
- D63 — Dinsmore
Dinsmore · elev 2,393 ft
- O16 — Garberville
Garberville · elev 551 ft
- O09 — Round Valley
Covelo · elev 1,434 ft
- H47 — Hyampom
Hyampom · elev 1,277 ft
- O54 — Lonnie Pool Field/Weaverville
Weaverville · elev 2,350 ft
- 0Q5 — Shelter Cove
Shelter Cove · elev 73 ft
- O19 — Kneeland
Eureka · elev 2,741 ft
Frequently asked questions
How high does density altitude get at T42 in summer?
On a typical July afternoon — around 95 °F at the nearest NOAA normals station — density altitude at Ruth reaches roughly 5,671 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 T42 on an average day?
It swings with the seasons: from roughly 2,100 ft at the coldest month's average temperature to about 4,374 ft at the warmest month's — all from a constant field elevation of 2,781 ft. The month-by-month table above carries the full year.
What is the field elevation of Ruth?
2,781 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is T42 (FAA), in Ruth, California.