Seattle, Washington · field elev 432 ft
Density Altitude at Seattle-Tacoma International (KSEA)
Seattle-Tacoma International sits at 432 ft, and even a typical August afternoon (78 °F) only lifts density altitude to about 1,746 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 | 42.8 | −532 ft | 48.0 | −180 ft |
| February | 44.0 | −451 ft | 50.3 | −25 ft |
| March | 47.1 | −241 ft | 54.2 | 235 ft |
| April | 51.3 | 42 ft | 59.3 | 571 ft |
| May | 57.5 | 453 ft | 66.3 | 1,026 ft |
| June | 62.0 | 748 ft | 71.1 | 1,334 ft |
| July | 67.1 | 1,078 ft | 77.4 | 1,733 ft |
| August | 67.4 | 1,097 ft | 77.6 | 1,746 ft |
| September | 62.6 | 787 ft | 71.6 | 1,366 ft |
| October | 53.8 | 208 ft | 60.5 | 650 ft |
| November | 46.5 | −281 ft | 52.1 | 95 ft |
| December | 42.0 | −587 ft | 47.0 | −247 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 KSEA
DENSITY ALTITUDE
Field elevation 432 ft — the air behaves like 1,771 ft.
- PRESSURE ALT
- 433 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
- KRNT — Renton Municipal
Renton · elev 32 ft
- KBFI — Boeing Field/King County International
Seattle · elev 22 ft
- 2S1 — Vashon Municipal
Vashon · elev 316 ft
- S50 — Auburn Municipal
Auburn · elev 63 ft
- S36 — Crest Airfield
Covington · elev 472 ft
- KTIW — Tacoma Narrows
Tacoma · elev 295 ft
- KPWT — Bremerton Ntl
Bremerton · elev 444 ft
- KPLU — Pierce County/Thun Field
Puyallup · elev 538 ft
Frequently asked questions
How high does density altitude get at KSEA in summer?
On a typical August afternoon — around 78 °F at the nearest NOAA normals station — density altitude at Seattle-Tacoma International reaches roughly 1,746 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 KSEA on an average day?
It swings with the seasons: from roughly −587 ft at the coldest month's average temperature to about 1,097 ft at the warmest month's — all from a constant field elevation of 432 ft. The month-by-month table above carries the full year.
What is the field elevation of Seattle-Tacoma International?
432 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KSEA (ICAO) / SEA (FAA), in Seattle, Washington.