Island Pond, Vermont · field elev 1,194 ft
Density Altitude at John H Boylan State (Island Pond) (5B1)
John H Boylan State (Island Pond) sits at 1,194 ft, and even a typical July afternoon (77 °F) only lifts density altitude to about 2,621 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 | 12.0 | −1,756 ft | 25.1 | −812 ft |
| February | 12.4 | −1,727 ft | 27.5 | −643 ft |
| March | 21.9 | −1,040 ft | 36.0 | −50 ft |
| April | 38.4 | 115 ft | 49.9 | 892 ft |
| May | 52.0 | 1,031 ft | 64.0 | 1,815 ft |
| June | 60.0 | 1,556 ft | 71.8 | 2,313 ft |
| July | 65.3 | 1,899 ft | 76.7 | 2,621 ft |
| August | 63.5 | 1,783 ft | 75.6 | 2,553 ft |
| September | 55.9 | 1,289 ft | 68.2 | 2,085 ft |
| October | 43.4 | 455 ft | 54.8 | 1,216 ft |
| November | 31.4 | −369 ft | 41.0 | 292 ft |
| December | 19.6 | −1,205 ft | 29.8 | −481 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 5B1
DENSITY ALTITUDE
Field elevation 1,194 ft — the air behaves like 2,640 ft.
- PRESSURE ALT
- 1,195 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 Vermont fields
- KCDA — Caledonia County
Lyndonville · elev 1,188 ft
- KEFK — Northeast Kingdom International
Newport · elev 934 ft
- KMVL — Morrisville-Stowe State
Morrisville · elev 733 ft
- KMPV — Edward F Knapp State
Barre/Montpelier · elev 1,166 ft
- KFSO — Franklin County State
Highgate · elev 228 ft
- 2B9 — Post Mills
Post Mills · elev 696 ft
- 0B7 — Warren-Sugarbush
Warren · elev 1,470 ft
- KBTV — Patrick Leahy Burlington International
Burlington · elev 335 ft
Frequently asked questions
How high does density altitude get at 5B1 in summer?
On a typical July afternoon — around 77 °F at the nearest NOAA normals station — density altitude at John H Boylan State (Island Pond) reaches roughly 2,621 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 5B1 on an average day?
It swings with the seasons: from roughly −1,756 ft at the coldest month's average temperature to about 1,899 ft at the warmest month's — all from a constant field elevation of 1,194 ft. The month-by-month table above carries the full year.
What is the field elevation of John H Boylan State (Island Pond)?
1,194 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 5B1 (FAA), in Island Pond, Vermont.