San Antonio, Texas · field elev 1,040 ft
Density Altitude at San Geronimo Airpark (8T8)
San Geronimo Airpark sits at 1,040 ft, and even a typical August afternoon (99 °F) only lifts density altitude to about 3,765 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 | 53.9 | 967 ft | 65.1 | 1,697 ft |
| February | 58.0 | 1,236 ft | 69.7 | 1,991 ft |
| March | 64.5 | 1,658 ft | 76.0 | 2,389 ft |
| April | 71.4 | 2,099 ft | 83.3 | 2,843 ft |
| May | 78.1 | 2,521 ft | 89.1 | 3,199 ft |
| June | 83.7 | 2,868 ft | 94.8 | 3,544 ft |
| July | 85.8 | 2,997 ft | 97.1 | 3,681 ft |
| August | 86.4 | 3,034 ft | 98.5 | 3,765 ft |
| September | 81.4 | 2,726 ft | 92.7 | 3,417 ft |
| October | 73.1 | 2,207 ft | 84.5 | 2,917 ft |
| November | 62.7 | 1,542 ft | 74.3 | 2,282 ft |
| December | 55.0 | 1,039 ft | 65.7 | 1,735 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 8T8
DENSITY ALTITUDE
Field elevation 1,040 ft — the air behaves like 3,795 ft.
- PRESSURE ALT
- 1,041 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
- KCVB — Castroville Municipal
Castroville · elev 774 ft
- KSKF — Kelly Field
San Antonio · elev 691 ft
- 5C1 — Boerne Stage Airfield
San Antonio · elev 1,384 ft
- KSAT — San Antonio International
San Antonio · elev 809 ft
- T94 — Twin-Oaks
San Antonio · elev 873 ft
- KSSF — Stinson Municipal
San Antonio · elev 578 ft
- 74R — Horizon
San Antonio · elev 551 ft
- KHDO — South Texas Regional At Hondo
Hondo · elev 930 ft
Frequently asked questions
How high does density altitude get at 8T8 in summer?
On a typical August afternoon — around 99 °F at the nearest NOAA normals station — density altitude at San Geronimo Airpark reaches roughly 3,765 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 8T8 on an average day?
It swings with the seasons: from roughly 967 ft at the coldest month's average temperature to about 3,034 ft at the warmest month's — all from a constant field elevation of 1,040 ft. The month-by-month table above carries the full year.
What is the field elevation of San Geronimo Airpark?
1,040 ft MSL, from the FAA NASR airport record (28-day cycle effective 2026-08-06). The identifier is 8T8 (FAA), in San Antonio, Texas.