South Bend/Raymond/, Washington · field elev 13 ft
Density Altitude at Willapa Harbor (2S9)
Willapa Harbor sits at 13 ft, and even a typical August afternoon (73 °F) only lifts density altitude to about 928 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 | 40.5 | −1,211 ft | 47.9 | −706 ft |
| February | 41.5 | −1,143 ft | 50.5 | −531 ft |
| March | 44.3 | −951 ft | 54.0 | −297 ft |
| April | 47.6 | −727 ft | 57.9 | −38 ft |
| May | 53.1 | −357 ft | 63.3 | 316 ft |
| June | 57.0 | −98 ft | 66.7 | 537 ft |
| July | 61.1 | 172 ft | 71.4 | 839 ft |
| August | 61.6 | 205 ft | 72.8 | 928 ft |
| September | 57.9 | −38 ft | 70.2 | 762 ft |
| October | 50.1 | −558 ft | 60.5 | 133 ft |
| November | 43.4 | −1,012 ft | 51.7 | −451 ft |
| December | 39.5 | −1,280 ft | 46.6 | −795 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 2S9
DENSITY ALTITUDE
Field elevation 13 ft — the air behaves like 941 ft.
- PRESSURE ALT
- 14 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
- 14S — Westport
Westport · elev 14 ft
- KHQM — Bowerman Field
Hoquiam · elev 18 ft
- W04 — Ocean Shores Municipal
Ocean Shores · elev 15 ft
- 7W1 — Port Of Ilwaco
Ilwaco · elev 13 ft
- S16 — Copalis State
Copalis · elev 1 ft
- 8W9 — R & K Skyranch
Rochester · elev 149 ft
- KCLS — Chehalis-Centralia
Chehalis · elev 177 ft
- KOLM — Olympia Regional
Olympia · elev 208 ft
Frequently asked questions
How high does density altitude get at 2S9 in summer?
On a typical August afternoon — around 73 °F at the nearest NOAA normals station — density altitude at Willapa Harbor reaches roughly 928 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 2S9 on an average day?
It swings with the seasons: from roughly −1,280 ft at the coldest month's average temperature to about 205 ft at the warmest month's — all from a constant field elevation of 13 ft. The month-by-month table above carries the full year.
What is the field elevation of Willapa Harbor?
13 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 2S9 (FAA), in South Bend/Raymond/, Washington.