Marston Mills, Massachusetts · field elev 103 ft
Density Altitude at Cape Cod (2B1)
Cape Cod sits at 103 ft, and even a typical July afternoon (77 °F) only lifts density altitude to about 1,311 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 | 29.3 | −1,881 ft | 38.2 | −1,258 ft |
| February | 30.9 | −1,768 ft | 39.9 | −1,141 ft |
| March | 36.0 | −1,411 ft | 44.6 | −819 ft |
| April | 45.8 | −737 ft | 55.3 | −99 ft |
| May | 55.8 | −66 ft | 65.0 | 537 ft |
| June | 63.8 | 459 ft | 71.2 | 937 ft |
| July | 70.1 | 866 ft | 77.1 | 1,311 ft |
| August | 68.6 | 770 ft | 75.7 | 1,223 ft |
| September | 62.4 | 368 ft | 70.2 | 873 ft |
| October | 52.2 | −306 ft | 60.7 | 257 ft |
| November | 43.4 | −901 ft | 52.1 | −312 ft |
| December | 35.5 | −1,446 ft | 43.9 | −866 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 2B1
DENSITY ALTITUDE
Field elevation 103 ft — the air behaves like 1,305 ft.
- PRESSURE ALT
- 104 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 Massachusetts fields
- KHYA — Cape Cod Gateway
Hyannis · elev 54 ft
- 5B6 — Falmouth Airpark
Falmouth · elev 41 ft
- KCQX — Chatham Municipal
Chatham · elev 64 ft
- KPYM — Plymouth Municipal
Plymouth · elev 148 ft
- KMVY — Martha'S Vineyard
Vineyard Haven · elev 67 ft
- 1B2 — Katama Airpark
Edgartown · elev 18 ft
- KPVC — Provincetown Municipal
Provincetown · elev 8 ft
- KEWB — New Bedford Regional
New Bedford · elev 79 ft
Frequently asked questions
How high does density altitude get at 2B1 in summer?
On a typical July afternoon — around 77 °F at the nearest NOAA normals station — density altitude at Cape Cod reaches roughly 1,311 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 2B1 on an average day?
It swings with the seasons: from roughly −1,881 ft at the coldest month's average temperature to about 866 ft at the warmest month's — all from a constant field elevation of 103 ft. The month-by-month table above carries the full year.
What is the field elevation of Cape Cod?
103 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 2B1 (FAA), in Marston Mills, Massachusetts.