St Thomas, North Dakota · field elev 839 ft
Density Altitude at St Thomas Municipal (4S5)
St Thomas Municipal sits at 839 ft, and even a typical July afternoon (81 °F) only lifts density altitude to about 2,474 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 | 7.7 | −2,522 ft | 15.5 | −1,948 ft |
| February | 12.6 | −2,160 ft | 21.0 | −1,550 ft |
| March | 26.4 | −1,165 ft | 34.4 | −604 ft |
| April | 42.8 | −26 ft | 52.5 | 625 ft |
| May | 57.3 | 942 ft | 68.4 | 1,662 ft |
| June | 68.0 | 1,636 ft | 78.7 | 2,312 ft |
| July | 71.3 | 1,846 ft | 81.3 | 2,474 ft |
| August | 69.6 | 1,738 ft | 80.2 | 2,406 ft |
| September | 60.6 | 1,158 ft | 71.3 | 1,846 ft |
| October | 45.1 | 129 ft | 53.9 | 718 ft |
| November | 28.7 | −1,002 ft | 35.8 | −507 ft |
| December | 14.0 | −2,057 ft | 21.0 | −1,550 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 4S5
DENSITY ALTITUDE
Field elevation 839 ft — the air behaves like 2,456 ft.
- PRESSURE ALT
- 840 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 North Dakota fields
- D29 — Drayton Municipal
Drayton · elev 798 ft
- 2C8 — Cavalier Municipal
Cavalier · elev 892 ft
- KGAF — Hutson Field
Grafton · elev 825 ft
- Y37 — Park River - W C Skjerven Field
Park River · elev 1,104 ft
- D06 — Minto Municipal
Minto · elev 820 ft
- KPMB — Pembina Municipal
Pembina · elev 796 ft
- 96D — Walhalla Municipal
Walhalla · elev 953 ft
- D55 — Robertson Field
Langdon · elev 1,608 ft
Frequently asked questions
How high does density altitude get at 4S5 in summer?
On a typical July afternoon — around 81 °F at the nearest NOAA normals station — density altitude at St Thomas Municipal reaches roughly 2,474 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 4S5 on an average day?
It swings with the seasons: from roughly −2,522 ft at the coldest month's average temperature to about 1,846 ft at the warmest month's — all from a constant field elevation of 839 ft. The month-by-month table above carries the full year.
What is the field elevation of St Thomas Municipal?
839 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 4S5 (FAA), in St Thomas, North Dakota.