Richmond, Michigan · field elev 650 ft
Density Altitude at Robertson Field (D99)
Robertson Field sits at 650 ft, and even a typical July afternoon (83 °F) only lifts density altitude to about 2,349 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 | 23.2 | −1,629 ft | 30.1 | −1,140 ft |
| February | 24.4 | −1,544 ft | 32.8 | −951 ft |
| March | 33.5 | −902 ft | 42.1 | −309 ft |
| April | 45.8 | −58 ft | 56.2 | 637 ft |
| May | 57.9 | 748 ft | 68.5 | 1,436 ft |
| June | 68.0 | 1,404 ft | 78.4 | 2,063 ft |
| July | 72.5 | 1,691 ft | 83.0 | 2,349 ft |
| August | 69.7 | 1,512 ft | 80.0 | 2,162 ft |
| September | 62.5 | 1,049 ft | 73.1 | 1,729 ft |
| October | 50.7 | 272 ft | 60.3 | 906 ft |
| November | 39.1 | −515 ft | 46.5 | −11 ft |
| December | 29.3 | −1,196 ft | 35.4 | −770 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 D99
DENSITY ALTITUDE
Field elevation 650 ft — the air behaves like 2,349 ft.
- PRESSURE ALT
- 651 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 Michigan fields
- 76G — Marine City
Marine City · elev 614 ft
- KPHN — St Clair County International
Port Huron · elev 650 ft
- 2E2 — Sharpe'S Strip
Emmett · elev 781 ft
- 57D — Ray Community
Ray · elev 632 ft
- 39G — Avoca
Avoca · elev 726 ft
- D98 — Romeo State
Romeo · elev 738 ft
- D20 — Yale
Yale · elev 815 ft
- 4Y8 — Para Field
Yale · elev 800 ft
Frequently asked questions
How high does density altitude get at D99 in summer?
On a typical July afternoon — around 83 °F at the nearest NOAA normals station — density altitude at Robertson Field reaches roughly 2,349 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 D99 on an average day?
It swings with the seasons: from roughly −1,629 ft at the coldest month's average temperature to about 1,691 ft at the warmest month's — all from a constant field elevation of 650 ft. The month-by-month table above carries the full year.
What is the field elevation of Robertson Field?
650 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is D99 (FAA), in Richmond, Michigan.