Standard atmosphere
The ICAO standard atmosphere (Doc 7488, the same as ISO 2533) from −5 to 80 km, or one of the database's older models: temperature, pressure, density and speed of sound at any altitude.
At 0 ft pressure altitude
The ICAO standard atmosphere
| Pressure altitude (geopotential) | 0 ft | 0.0 m | |
|---|---|---|---|
| Height above sea level (geometric) | 0 ft | 0.0 m | |
| Temperature | 15.00 °C | 288.15 K | θ = 1.0000 |
| Pressure | 1,013.25 hPa | 29.92 inHg · 14.696 psi | δ = 1.00000 |
| Density | 1.22500 kg/m³ | σ = 1.00000 | |
| Speed of sound | 661.5 kt | 340.29 m/s | |
| Dynamic viscosity | 1.7894E-5 Pa·s | ||
| Kinematic viscosity | 1.4607E-5 m²/s | ||
| Gravity | 9.8067 m/s² |
Profile
The standard levels as a table
| Altitude (ft) | Temperature (°C) | Pressure (hPa) | Density (kg/m³) | σ | Speed of sound (kt) |
|---|---|---|---|---|---|
| -2,000 | 18.96 | 1,088.66 | 1.29831 | 1.0598 | 666.0 |
| 0 | 15.00 | 1,013.25 | 1.22500 | 1.0000 | 661.5 |
| 2,000 | 11.04 | 942.13 | 1.15490 | 0.9428 | 656.9 |
| 4,000 | 7.08 | 875.11 | 1.08791 | 0.8881 | 652.3 |
| 6,000 | 3.11 | 812.00 | 1.02393 | 0.8359 | 647.7 |
| 8,000 | -0.85 | 752.62 | 0.96287 | 0.7860 | 643.0 |
| 10,000 | -4.81 | 696.82 | 0.90464 | 0.7385 | 638.3 |
| 12,000 | -8.77 | 644.41 | 0.84914 | 0.6932 | 633.6 |
| 14,000 | -12.74 | 595.24 | 0.79628 | 0.6500 | 628.8 |
| 16,000 | -16.70 | 549.15 | 0.74598 | 0.6090 | 624.0 |
| 18,000 | -20.66 | 506.00 | 0.69815 | 0.5699 | 619.2 |
| 20,000 | -24.62 | 465.63 | 0.65269 | 0.5328 | 614.3 |
| 22,000 | -28.59 | 427.91 | 0.60954 | 0.4976 | 609.4 |
| 24,000 | -32.55 | 392.71 | 0.56861 | 0.4642 | 604.4 |
| 26,000 | -36.51 | 359.89 | 0.52981 | 0.4325 | 599.4 |
| 28,000 | -40.47 | 329.32 | 0.49307 | 0.4025 | 594.4 |
| 30,000 | -44.44 | 300.90 | 0.45831 | 0.3741 | 589.3 |
| 32,000 | -48.40 | 274.49 | 0.42546 | 0.3473 | 584.2 |
| 34,000 | -52.36 | 249.99 | 0.39444 | 0.3220 | 579.0 |
| 36,000 | -56.32 | 227.29 | 0.36518 | 0.2981 | 573.8 |
| 38,000 | -56.50 | 206.46 | 0.33199 | 0.2710 | 573.6 |
| 40,000 | -56.50 | 187.54 | 0.30156 | 0.2462 | 573.6 |
| 42,000 | -56.50 | 170.35 | 0.27392 | 0.2236 | 573.6 |
| 44,000 | -56.50 | 154.74 | 0.24881 | 0.2031 | 573.6 |
| 46,000 | -56.50 | 140.56 | 0.22601 | 0.1845 | 573.6 |
| 48,000 | -56.50 | 127.67 | 0.20530 | 0.1676 | 573.6 |
| 50,000 | -56.50 | 115.97 | 0.18648 | 0.1522 | 573.6 |
| 52,000 | -56.50 | 105.34 | 0.16939 | 0.1383 | 573.6 |
| 54,000 | -56.50 | 95.69 | 0.15386 | 0.1256 | 573.6 |
| 56,000 | -56.50 | 86.92 | 0.13976 | 0.1141 | 573.6 |
| 58,000 | -56.50 | 78.95 | 0.12695 | 0.1036 | 573.6 |
| 60,000 | -56.50 | 71.72 | 0.11532 | 0.0941 | 573.6 |
Dry air as a perfect gas: R = 287.05287 J/(kg·K), κ = 1.4, g₀ = 9.80665 m/s², sea level 288.15 K and 101,325 Pa; viscosity by Sutherland's law. Altitudes are geopotential (the altimeter's) unless marked geometric. An ISA deviation changes the temperature and the density, not the pressure at a pressure altitude. Source: ICAO Doc 7488/3, Manual of the ICAO Standard Atmosphere (1993). The database's standard atmospheres use their own layer rows: their base temperatures and pressures as their tables gave them (rounded in some), with the same constants; a row without a geopotential altitude uses the altitude of its geometric column. Their layers can be read and corrected in the database (Standard atmosphere layers).