Fort Madison, Iowa · field elev 722 ft
Density Altitude at Fort Madison Municipal (KFSW)
Fort Madison Municipal sits at 722 ft, and even a typical July afternoon (85 °F) only lifts density altitude to about 2,566 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 | 24.8 | −1,425 ft | 32.8 | −861 ft |
| February | 29.2 | −1,113 ft | 37.5 | −535 ft |
| March | 40.8 | −308 ft | 49.9 | 307 ft |
| April | 52.4 | 474 ft | 62.2 | 1,118 ft |
| May | 63.1 | 1,176 ft | 72.3 | 1,766 ft |
| June | 72.5 | 1,779 ft | 81.5 | 2,344 ft |
| July | 76.3 | 2,019 ft | 85.1 | 2,566 ft |
| August | 74.7 | 1,918 ft | 83.8 | 2,486 ft |
| September | 67.1 | 1,434 ft | 77.1 | 2,069 ft |
| October | 54.7 | 626 ft | 64.2 | 1,248 ft |
| November | 41.3 | −274 ft | 49.7 | 294 ft |
| December | 30.2 | −1,043 ft | 37.6 | −528 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 KFSW
DENSITY ALTITUDE
Field elevation 722 ft — the air behaves like 2,560 ft.
- PRESSURE ALT
- 723 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 Iowa fields
- KBRL — Southeast Iowa Regional
Burlington · elev 699 ft
- KEOK — Keokuk Municipal
Keokuk · elev 672 ft
- KMPZ — Mount Pleasant Municipal
Mount Pleasant · elev 731 ft
- 6K9 — Keosauqua Municipal
Keosauqua · elev 580 ft
- KFFL — Fairfield Municipal
Fairfield · elev 801 ft
- KAWG — Washington Municipal
Washington · elev 754 ft
- KMUT — Muscatine Municipal
Muscatine · elev 547 ft
- 4K6 — Bloomfield Municipal
Bloomfield · elev 888 ft
Frequently asked questions
How high does density altitude get at KFSW in summer?
On a typical July afternoon — around 85 °F at the nearest NOAA normals station — density altitude at Fort Madison Municipal reaches roughly 2,566 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 KFSW on an average day?
It swings with the seasons: from roughly −1,425 ft at the coldest month's average temperature to about 2,019 ft at the warmest month's — all from a constant field elevation of 722 ft. The month-by-month table above carries the full year.
What is the field elevation of Fort Madison Municipal?
722 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KFSW (ICAO) / FSW (FAA), in Fort Madison, Iowa.