Madison, Wisconsin · field elev 920 ft
Density Altitude at Blackhawk Airfield (87Y)
Blackhawk Airfield sits at 920 ft, and even a typical July afternoon (82 °F) only lifts density altitude to about 2,623 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 | 19.4 | −1,563 ft | 27.0 | −1,021 ft |
| February | 23.0 | −1,305 ft | 31.2 | −726 ft |
| March | 34.4 | −503 ft | 43.6 | 128 ft |
| April | 46.3 | 311 ft | 56.9 | 1,016 ft |
| May | 58.1 | 1,095 ft | 69.0 | 1,799 ft |
| June | 68.0 | 1,735 ft | 78.6 | 2,405 ft |
| July | 71.9 | 1,984 ft | 82.1 | 2,623 ft |
| August | 69.7 | 1,844 ft | 79.9 | 2,486 ft |
| September | 62.0 | 1,349 ft | 72.9 | 2,047 ft |
| October | 49.7 | 539 ft | 59.6 | 1,193 ft |
| November | 36.7 | −343 ft | 44.8 | 210 ft |
| December | 25.3 | −1,141 ft | 32.3 | −649 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 87Y
DENSITY ALTITUDE
Field elevation 920 ft — the air behaves like 2,617 ft.
- PRESSURE ALT
- 921 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 Wisconsin fields
- KMSN — Dane County Regional/Truax Field
Madison · elev 887 ft
- 6P3 — Waunakee
Waunakee · elev 954 ft
- 58C — Jana
Edgerton · elev 843 ft
- C29 — Middleton Municipal/Morey Field
Middleton · elev 928 ft
- 61C — Fort Atkinson Municipal
Fort Atkinson · elev 800 ft
- KRYV — Watertown Municipal
Watertown · elev 833 ft
- 94C — Gilbert Field
Rio · elev 927 ft
- 5Y3 — Gutzmer'S Twin Oaks
Whitewater · elev 821 ft
Frequently asked questions
How high does density altitude get at 87Y in summer?
On a typical July afternoon — around 82 °F at the nearest NOAA normals station — density altitude at Blackhawk Airfield reaches roughly 2,623 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 87Y on an average day?
It swings with the seasons: from roughly −1,563 ft at the coldest month's average temperature to about 1,984 ft at the warmest month's — all from a constant field elevation of 920 ft. The month-by-month table above carries the full year.
What is the field elevation of Blackhawk Airfield?
920 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 87Y (FAA), in Madison, Wisconsin.