Gleneden Beach, Oregon · field elev 69 ft
Density Altitude at Siletz Bay State (S45)
Siletz Bay State sits at 69 ft, and even a typical August afternoon (72 °F) only lifts density altitude to about 965 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 | 43.1 | −963 ft | 48.5 | −596 ft |
| February | 44.6 | −861 ft | 51.5 | −395 ft |
| March | 47.0 | −698 ft | 55.1 | −154 ft |
| April | 49.7 | −516 ft | 58.6 | 77 ft |
| May | 54.0 | −228 ft | 63.2 | 378 ft |
| June | 57.4 | −2 ft | 66.4 | 586 ft |
| July | 61.1 | 241 ft | 71.0 | 882 ft |
| August | 61.9 | 294 ft | 72.3 | 965 ft |
| September | 59.6 | 143 ft | 70.0 | 818 ft |
| October | 53.2 | −281 ft | 61.3 | 254 ft |
| November | 46.7 | −718 ft | 52.7 | −314 ft |
| December | 42.4 | −1,011 ft | 47.7 | −650 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 S45
DENSITY ALTITUDE
Field elevation 69 ft — the air behaves like 946 ft.
- PRESSURE ALT
- 70 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 Oregon fields
- 5S4 — Toledo State
Toledo · elev 12 ft
- KONP — Newport Municipal
Newport · elev 160 ft
- KPFC — Pacific City State
Pacific City · elev 10 ft
- R33 — Wakonda Beach State
Waldport · elev 41 ft
- KTMK — Tillamook
Tillamook · elev 39 ft
- 7S5 — Independence State
Independence · elev 180 ft
- KCVO — Corvallis Municipal
Corvallis · elev 250 ft
- KMMV — Mc Minnville Municipal
Mc Minnville · elev 163 ft
Frequently asked questions
How high does density altitude get at S45 in summer?
On a typical August afternoon — around 72 °F at the nearest NOAA normals station — density altitude at Siletz Bay State reaches roughly 965 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 S45 on an average day?
It swings with the seasons: from roughly −1,011 ft at the coldest month's average temperature to about 294 ft at the warmest month's — all from a constant field elevation of 69 ft. The month-by-month table above carries the full year.
What is the field elevation of Siletz Bay State?
69 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is S45 (FAA), in Gleneden Beach, Oregon.