Presidio, Texas · field elev 4,250 ft
Density Altitude at Big Bend Ranch State Park (3T9)
From a field elevation of 4,250 ft, a typical June afternoon at Big Bend Ranch State Park (94 °F) raises density altitude to about 7,389 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 | 46.2 | 4,424 ft | 61.9 | 5,432 ft ▲ |
| February | 51.5 | 4,768 ft | 67.5 | 5,783 ft ▲ |
| March | 58.0 | 5,185 ft | 74.7 | 6,227 ft ▲ |
| April | 66.7 | 5,733 ft | 82.3 | 6,688 ft ▲ |
| May | 74.5 | 6,215 ft | 89.5 | 7,118 ft ▲ |
| June | 80.7 | 6,592 ft | 94.1 | 7,389 ft ▲ |
| July | 79.9 | 6,544 ft | 91.8 | 7,253 ft ▲ |
| August | 78.8 | 6,477 ft | 90.4 | 7,171 ft ▲ |
| September | 73.8 | 6,172 ft | 85.8 | 6,898 ft ▲ |
| October | 65.9 | 5,683 ft | 80.1 | 6,556 ft ▲ |
| November | 54.6 | 4,968 ft | 69.3 | 5,895 ft ▲ |
| December | 46.3 | 4,430 ft | 62.1 | 5,445 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 3T9
DENSITY ALTITUDE caution
Field elevation 4,250 ft — the air behaves like 7,383 ft.
- PRESSURE ALT
- 4,252 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
- T89 — Lajitas International
Lajitas · elev 2,630 ft
- KPRS — Presidio Lely International
Presidio · elev 2,938 ft
- 1E2 — Terlingua Ranch
Alpine · elev 3,769 ft
- KMRF — Marfa Municipal
Marfa · elev 4,849 ft
- E38 — Alpine-Casparis Municipal
Alpine · elev 4,514 ft
- 6R6 — Terrell County
Dryden · elev 2,323 ft
- KFST — Fort Stockton-Pecos County
Fort Stockton · elev 3,011 ft
- KVHN — Culberson County
Van Horn · elev 3,957 ft
Frequently asked questions
How high does density altitude get at 3T9 in summer?
On a typical June afternoon — around 94 °F at the nearest NOAA normals station — density altitude at Big Bend Ranch State Park reaches roughly 7,389 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 3T9 on an average day?
It swings with the seasons: from roughly 4,424 ft at the coldest month's average temperature to about 6,592 ft at the warmest month's — all from a constant field elevation of 4,250 ft. The month-by-month table above carries the full year.
What is the field elevation of Big Bend Ranch State Park?
4,250 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 3T9 (FAA), in Presidio, Texas.