Copalis, Washington · field elev 1 ft
Density Altitude at Copalis State (S16)
Copalis State sits at 1 ft, and even a typical August afternoon (70 °F) only lifts density altitude to about 754 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 | 40.0 | −1,261 ft | 45.4 | −891 ft |
| February | 40.6 | −1,220 ft | 47.5 | −748 ft |
| March | 43.0 | −1,055 ft | 51.2 | −499 ft |
| April | 46.3 | −830 ft | 55.1 | −239 ft |
| May | 51.8 | −459 ft | 61.3 | 170 ft |
| June | 55.6 | −205 ft | 64.4 | 373 ft |
| July | 59.6 | 59 ft | 69.4 | 696 ft |
| August | 60.1 | 92 ft | 70.3 | 754 ft |
| September | 56.7 | −132 ft | 67.0 | 541 ft |
| October | 49.4 | −620 ft | 57.9 | −53 ft |
| November | 42.8 | −1,068 ft | 49.3 | −627 ft |
| December | 39.1 | −1,323 ft | 44.4 | −959 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 S16
DENSITY ALTITUDE
Field elevation 1 ft — the air behaves like 734 ft.
- PRESSURE ALT
- 2 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
- W04 — Ocean Shores Municipal
Ocean Shores · elev 15 ft
- KHQM — Bowerman Field
Hoquiam · elev 18 ft
- 14S — Westport
Westport · elev 14 ft
- 2S9 — Willapa Harbor
South Bend/Raymond/ · elev 13 ft
- KSHN — Sanderson Field
Shelton · elev 273 ft
- S18 — Forks
Forks · elev 299 ft
- 8W9 — R & K Skyranch
Rochester · elev 149 ft
- KUIL — Quillayute
Quillayute · elev 194 ft
Frequently asked questions
How high does density altitude get at S16 in summer?
On a typical August afternoon — around 70 °F at the nearest NOAA normals station — density altitude at Copalis State reaches roughly 754 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 S16 on an average day?
It swings with the seasons: from roughly −1,323 ft at the coldest month's average temperature to about 92 ft at the warmest month's — all from a constant field elevation of 1 ft. The month-by-month table above carries the full year.
What is the field elevation of Copalis State?
1 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is S16 (FAA), in Copalis, Washington.