Big Lake, Texas · field elev 2,706 ft
Density Altitude at Reagan County (E41)
From a field elevation of 2,706 ft, a typical August afternoon at Reagan County (95 °F) raises density altitude to about 5,575 ft — solidly into the range where performance charts deserve a close read.
Typical density altitude by month
| Month | Avg temp °F | DA at avg temp | Afternoon high °F | DA on a typical afternoon |
|---|---|---|---|---|
| January | 46.9 | 2,563 ft | 60.4 | 3,443 ft |
| February | 51.1 | 2,840 ft | 65.3 | 3,755 ft |
| March | 58.8 | 3,340 ft | 72.9 | 4,233 ft |
| April | 66.6 | 3,837 ft | 81.5 | 4,763 ft |
| May | 74.1 | 4,307 ft | 87.7 | 5,139 ft ▲ |
| June | 80.6 | 4,708 ft | 92.6 | 5,432 ft ▲ |
| July | 82.7 | 4,836 ft | 94.3 | 5,533 ft ▲ |
| August | 82.5 | 4,824 ft | 95.0 | 5,575 ft ▲ |
| September | 75.8 | 4,413 ft | 88.6 | 5,193 ft ▲ |
| October | 66.9 | 3,856 ft | 80.1 | 4,677 ft |
| November | 55.7 | 3,140 ft | 69.1 | 3,995 ft |
| December | 48.2 | 2,649 ft | 61.2 | 3,494 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 E41
DENSITY ALTITUDE caution
Field elevation 2,706 ft — the air behaves like 5,575 ft.
- PRESSURE ALT
- 2,708 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 Texas fields
- 49F — Rankin
Rankin · elev 2,543 ft
- 2F0 — Iraan Municipal
Iraan · elev 2,200 ft
- KOZA — Ozona Municipal
Ozona · elev 2,377 ft
- E48 — Upton County
Mc Camey · elev 2,433 ft
- E13 — Crane County
Crane · elev 2,555 ft
- 27R — Eldorado
Eldorado · elev 2,448 ft
- 7T7 — Skywest Inc
Midland · elev 2,805 ft
- KSJT — San Angelo Regional/Mathis Field
San Angelo · elev 1,919 ft
Frequently asked questions
How high does density altitude get at E41 in summer?
On a typical August afternoon — around 95 °F at the nearest NOAA normals station — density altitude at Reagan County reaches roughly 5,575 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 E41 on an average day?
It swings with the seasons: from roughly 2,563 ft at the coldest month's average temperature to about 4,836 ft at the warmest month's — all from a constant field elevation of 2,706 ft. The month-by-month table above carries the full year.
What is the field elevation of Reagan County?
2,706 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is E41 (FAA), in Big Lake, Texas.