Sekiu, Washington · field elev 355 ft
Density Altitude at Sekiu (11S)
Sekiu sits at 355 ft, and even a typical August afternoon (74 °F) only lifts density altitude to about 1,424 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 | 40.7 | −772 ft | 46.9 | −350 ft |
| February | 42.0 | −683 ft | 49.9 | −148 ft |
| March | 44.4 | −519 ft | 53.3 | 80 ft |
| April | 48.3 | −255 ft | 58.7 | 437 ft |
| May | 53.6 | 100 ft | 64.5 | 815 ft |
| June | 57.5 | 358 ft | 68.0 | 1,041 ft |
| July | 61.6 | 627 ft | 73.1 | 1,367 ft |
| August | 62.3 | 672 ft | 74.0 | 1,424 ft |
| September | 58.8 | 443 ft | 70.1 | 1,176 ft |
| October | 51.2 | −60 ft | 60.0 | 522 ft |
| November | 44.0 | −546 ft | 50.6 | −101 ft |
| December | 39.8 | −834 ft | 45.6 | −438 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 11S
DENSITY ALTITUDE
Field elevation 355 ft — the air behaves like 1,424 ft.
- PRESSURE ALT
- 356 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 Washington fields
- S18 — Forks
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- KUIL — Quillayute
Quillayute · elev 194 ft
- KCLM — William R Fairchild International
Port Angeles · elev 291 ft
- W28 — Sequim Valley
Sequim · elev 151 ft
- KFHR — Friday Harbor
Friday Harbor · elev 113 ft
- S31 — Lopez Island
Lopez · elev 209 ft
- 0S9 — Jefferson County International
Port Townsend · elev 110 ft
- KORS — Orcas Island
Eastsound · elev 35 ft
Frequently asked questions
How high does density altitude get at 11S in summer?
On a typical August afternoon — around 74 °F at the nearest NOAA normals station — density altitude at Sekiu reaches roughly 1,424 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 11S on an average day?
It swings with the seasons: from roughly −834 ft at the coldest month's average temperature to about 672 ft at the warmest month's — all from a constant field elevation of 355 ft. The month-by-month table above carries the full year.
What is the field elevation of Sekiu?
355 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 11S (FAA), in Sekiu, Washington.