Sequim, Washington · field elev 151 ft
Density Altitude at Sequim Valley (W28)
Sequim Valley sits at 151 ft, and even a typical August afternoon (70 °F) only lifts density altitude to about 944 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 | 39.2 | −1,129 ft | 46.2 | −650 ft |
| February | 39.9 | −1,081 ft | 47.8 | −542 ft |
| March | 42.9 | −875 ft | 51.3 | −306 ft |
| April | 46.8 | −610 ft | 55.8 | −7 ft |
| May | 52.9 | −199 ft | 61.5 | 369 ft |
| June | 57.1 | 79 ft | 65.4 | 622 ft |
| July | 60.8 | 323 ft | 70.0 | 919 ft |
| August | 60.7 | 316 ft | 70.4 | 944 ft |
| September | 56.0 | 7 ft | 65.9 | 655 ft |
| October | 48.7 | −481 ft | 57.5 | 106 ft |
| November | 42.5 | −902 ft | 50.4 | −367 ft |
| December | 38.8 | −1,157 ft | 45.9 | −671 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 W28
DENSITY ALTITUDE
Field elevation 151 ft — the air behaves like 919 ft.
- PRESSURE ALT
- 152 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
- KCLM — William R Fairchild International
Port Angeles · elev 291 ft
- 0S9 — Jefferson County International
Port Townsend · elev 110 ft
- KOKH — Delaurentis
Oak Harbor · elev 193 ft
- S31 — Lopez Island
Lopez · elev 209 ft
- KFHR — Friday Harbor
Friday Harbor · elev 113 ft
- W10 — Whidbey Air Park
Langley · elev 271 ft
- 13W — Camano Island Airfield
Stanwood · elev 145 ft
- 74S — Anacortes
Anacortes · elev 246 ft
Frequently asked questions
How high does density altitude get at W28 in summer?
On a typical August afternoon — around 70 °F at the nearest NOAA normals station — density altitude at Sequim Valley reaches roughly 944 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 W28 on an average day?
It swings with the seasons: from roughly −1,157 ft at the coldest month's average temperature to about 323 ft at the warmest month's — all from a constant field elevation of 151 ft. The month-by-month table above carries the full year.
What is the field elevation of Sequim Valley?
151 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is W28 (FAA), in Sequim, Washington.