Sussex, New Jersey · field elev 422 ft
Density Altitude at Sussex (KFWN)
Sussex sits at 422 ft, and even a typical July afternoon (84 °F) only lifts density altitude to about 2,108 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 | 27.0 | −1,644 ft | 36.0 | −1,013 ft |
| February | 29.4 | −1,475 ft | 39.3 | −785 ft |
| March | 37.5 | −909 ft | 47.7 | −212 ft |
| April | 48.8 | −138 ft | 60.9 | 664 ft |
| May | 59.2 | 552 ft | 71.4 | 1,341 ft |
| June | 67.7 | 1,104 ft | 79.5 | 1,852 ft |
| July | 72.2 | 1,392 ft | 83.6 | 2,108 ft |
| August | 70.8 | 1,303 ft | 82.0 | 2,008 ft |
| September | 62.7 | 781 ft | 74.6 | 1,544 ft |
| October | 51.9 | 69 ft | 63.5 | 833 ft |
| November | 41.2 | −654 ft | 51.4 | 36 ft |
| December | 32.3 | −1,271 ft | 40.7 | −688 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 KFWN
DENSITY ALTITUDE
Field elevation 422 ft — the air behaves like 2,133 ft.
- PRESSURE ALT
- 423 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 New Jersey fields
- 12N — Aeroflex/Andover
Andover · elev 583 ft
- 4N1 — Greenwood Lake
West Milford · elev 790 ft
- N07 — Lincoln Park
Lincoln Park · elev 181 ft
- 1N7 — Blairstown
Blairstown · elev 372 ft
- KCDW — Essex County
Caldwell · elev 172 ft
- N05 — Hackettstown
Hackettstown · elev 670 ft
- KMMU — Morristown Municipal
Morristown · elev 187 ft
- KTEB — Teterboro
Teterboro · elev 8 ft
Frequently asked questions
How high does density altitude get at KFWN in summer?
On a typical July afternoon — around 84 °F at the nearest NOAA normals station — density altitude at Sussex reaches roughly 2,108 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 KFWN on an average day?
It swings with the seasons: from roughly −1,644 ft at the coldest month's average temperature to about 1,392 ft at the warmest month's — all from a constant field elevation of 422 ft. The month-by-month table above carries the full year.
What is the field elevation of Sussex?
422 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KFWN (ICAO) / FWN (FAA), in Sussex, New Jersey.