Portsmouth, New Hampshire · field elev 100 ft
Density Altitude at Portsmouth International At Pease (KPSM)
Portsmouth International At Pease sits at 100 ft, and even a typical July afternoon (81 °F) only lifts density altitude to about 1,521 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 | 24.4 | −2,234 ft | 32.6 | −1,652 ft |
| February | 26.6 | −2,076 ft | 35.6 | −1,442 ft |
| March | 34.3 | −1,533 ft | 43.3 | −911 ft |
| April | 45.3 | −775 ft | 55.8 | −70 ft |
| May | 55.4 | −96 ft | 66.1 | 605 ft |
| June | 64.5 | 501 ft | 75.0 | 1,175 ft |
| July | 70.3 | 875 ft | 80.5 | 1,521 ft |
| August | 69.1 | 798 ft | 79.4 | 1,452 ft |
| September | 61.7 | 319 ft | 71.8 | 971 ft |
| October | 50.1 | −450 ft | 59.7 | 188 ft |
| November | 39.7 | −1,158 ft | 48.1 | −585 ft |
| December | 30.0 | −1,835 ft | 37.8 | −1,290 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 KPSM
DENSITY ALTITUDE
Field elevation 100 ft — the air behaves like 1,552 ft.
- PRESSURE ALT
- 101 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 New Hampshire fields
- 7B3 — Hampton Airfield
Hampton · elev 93 ft
- KDAW — Skyhaven
Rochester · elev 322 ft
- KMHT — Manchester Boston Regional
Manchester · elev 266 ft
- KCON — Concord Municipal
Concord · elev 342 ft
- KASH — Boire Field
Nashua · elev 200 ft
- KLCI — Laconia Municipal
Laconia · elev 545 ft
- 8B1 — Hawthorne-Feather Airpark
Hillsboro · elev 600 ft
- 4MB — Moultonborough
Moultonborough · elev 576 ft
Frequently asked questions
How high does density altitude get at KPSM in summer?
On a typical July afternoon — around 81 °F at the nearest NOAA normals station — density altitude at Portsmouth International At Pease reaches roughly 1,521 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 KPSM on an average day?
It swings with the seasons: from roughly −2,234 ft at the coldest month's average temperature to about 875 ft at the warmest month's — all from a constant field elevation of 100 ft. The month-by-month table above carries the full year.
What is the field elevation of Portsmouth International At Pease?
100 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is KPSM (ICAO) / PSM (FAA), in Portsmouth, New Hampshire.