Port Mansfield, Texas · field elev 10 ft
Density Altitude at Charles R Johnson (T05)
Charles R Johnson sits at 10 ft, and even a typical August afternoon (92 °F) only lifts density altitude to about 2,110 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 | 59.0 | 31 ft | 67.7 | 598 ft |
| February | 62.8 | 280 ft | 71.0 | 810 ft |
| March | 68.0 | 617 ft | 75.6 | 1,103 ft |
| April | 73.6 | 976 ft | 80.8 | 1,430 ft |
| May | 79.0 | 1,317 ft | 85.3 | 1,710 ft |
| June | 83.1 | 1,573 ft | 89.6 | 1,975 ft |
| July | 84.1 | 1,636 ft | 90.5 | 2,030 ft |
| August | 84.7 | 1,673 ft | 91.8 | 2,110 ft |
| September | 81.1 | 1,449 ft | 88.5 | 1,908 ft |
| October | 76.0 | 1,128 ft | 84.1 | 1,636 ft |
| November | 68.0 | 617 ft | 76.4 | 1,153 ft |
| December | 61.2 | 175 ft | 70.3 | 765 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 T05
DENSITY ALTITUDE
Field elevation 10 ft — the air behaves like 2,122 ft.
- PRESSURE ALT
- 11 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
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Edinburg · elev 75 ft
- KBRO — Brownsville/South Padre Island International
Brownsville · elev 22 ft
- KMFE — Mc Allen International
Mc Allen · elev 107 ft
- KBKS — Brooks County
Falfurrias · elev 112 ft
- 07R — Bishop-Windham
Bishop · elev 55 ft
Frequently asked questions
How high does density altitude get at T05 in summer?
On a typical August afternoon — around 92 °F at the nearest NOAA normals station — density altitude at Charles R Johnson reaches roughly 2,110 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 T05 on an average day?
It swings with the seasons: from roughly 31 ft at the coldest month's average temperature to about 1,673 ft at the warmest month's — all from a constant field elevation of 10 ft. The month-by-month table above carries the full year.
What is the field elevation of Charles R Johnson?
10 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is T05 (FAA), in Port Mansfield, Texas.