Hoopa, California · field elev 356 ft
Density Altitude at Hoopa (O21)
Hoopa sits at 356 ft, and even a typical July afternoon (92 °F) only lifts density altitude to about 2,543 ft — heat still trims performance, but the field rarely turns high-and-hot.
Typical density altitude by month
| Month | Avg temp °F | DA at avg temp | Afternoon high °F | DA on a typical afternoon |
|---|---|---|---|---|
| January | 43.4 | −586 ft | 49.6 | −166 ft |
| February | 47.0 | −342 ft | 54.9 | 187 ft |
| March | 51.4 | −46 ft | 61.8 | 641 ft |
| April | 55.8 | 247 ft | 68.3 | 1,062 ft |
| May | 62.3 | 674 ft | 76.7 | 1,596 ft |
| June | 67.6 | 1,017 ft | 83.1 | 1,996 ft |
| July | 74.4 | 1,451 ft | 92.0 | 2,543 ft |
| August | 73.4 | 1,387 ft | 91.0 | 2,482 ft |
| September | 68.7 | 1,087 ft | 85.8 | 2,163 ft |
| October | 58.6 | 431 ft | 70.9 | 1,228 ft |
| November | 48.8 | −220 ft | 55.6 | 234 ft |
| December | 42.5 | −647 ft | 47.9 | −281 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 O21
DENSITY ALTITUDE
Field elevation 356 ft — the air behaves like 2,543 ft.
- PRESSURE ALT
- 357 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
- KACV — California Redwood Coast-Humboldt County
Arcata/Eureka · elev 222 ft
- O19 — Kneeland
Eureka · elev 2,741 ft
- KEKA — Murray Field
Eureka · elev 11 ft
- H47 — Hyampom
Hyampom · elev 1,277 ft
- O33 — Samoa Field
Eureka · elev 20 ft
- S51 — Andy Mc Beth
Klamath Glen · elev 42 ft
- D63 — Dinsmore
Dinsmore · elev 2,393 ft
- KFOT — Rohnerville
Fortuna · elev 393 ft
Frequently asked questions
How high does density altitude get at O21 in summer?
On a typical July afternoon — around 92 °F at the nearest NOAA normals station — density altitude at Hoopa reaches roughly 2,543 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 O21 on an average day?
It swings with the seasons: from roughly −647 ft at the coldest month's average temperature to about 1,451 ft at the warmest month's — all from a constant field elevation of 356 ft. The month-by-month table above carries the full year.
What is the field elevation of Hoopa?
356 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is O21 (FAA), in Hoopa, California.