Patterson, Louisiana · field elev 9 ft
Density Altitude at Harry P Williams Meml (KPTN)
Harry P Williams Meml sits at 9 ft, and even a typical July afternoon (91 °F) only lifts density altitude to about 2,029 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 | 54.2 | −289 ft | 63.0 | 291 ft |
| February | 57.7 | −56 ft | 66.5 | 519 ft |
| March | 63.2 | 304 ft | 71.8 | 860 ft |
| April | 69.5 | 712 ft | 78.0 | 1,253 ft |
| May | 76.4 | 1,152 ft | 84.1 | 1,634 ft |
| June | 81.7 | 1,485 ft | 88.9 | 1,931 ft |
| July | 83.4 | 1,591 ft | 90.5 | 2,029 ft |
| August | 83.3 | 1,585 ft | 90.4 | 2,023 ft |
| September | 80.5 | 1,410 ft | 87.9 | 1,869 ft |
| October | 72.4 | 898 ft | 81.1 | 1,447 ft |
| November | 62.5 | 259 ft | 72.0 | 872 ft |
| December | 56.6 | −129 ft | 65.6 | 461 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 KPTN
DENSITY ALTITUDE
Field elevation 9 ft — the air behaves like 2,060 ft.
- PRESSURE ALT
- 10 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 Louisiana fields
- 2R1 — Le Maire Meml
Jeanerette · elev 14 ft
- L83 — Thibodaux Municipal
Thibodaux · elev 9 ft
- KARA — Acadiana Regional
New Iberia · elev 24 ft
- KREG — Louisiana Regional
Gonzales · elev 14 ft
- KHUM — Houma-Terrebonne
Houma · elev 9 ft
- KIYA — Abbeville Chris Crusta Meml
Abbeville · elev 16 ft
- KLFT — Lafayette Regional/Paul Fournet Field
Lafayette · elev 41 ft
- KAPS — Port Of South Louisiana Exec Regional
Reserve · elev 7 ft
Frequently asked questions
How high does density altitude get at KPTN in summer?
On a typical July afternoon — around 91 °F at the nearest NOAA normals station — density altitude at Harry P Williams Meml reaches roughly 2,029 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 KPTN on an average day?
It swings with the seasons: from roughly −289 ft at the coldest month's average temperature to about 1,591 ft at the warmest month's — all from a constant field elevation of 9 ft. The month-by-month table above carries the full year.
What is the field elevation of Harry P Williams Meml?
9 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KPTN (ICAO) / PTN (FAA), in Patterson, Louisiana.