# Velocity of Sound in Dry Air

Sound is a vibration that travels through an elastic medium as a wave. The speed of sound describes how far this wave travels in a given amount of time. In dry air at 20 °C (68 °F), the speed of sound is 343 meters per second (1,125 ft/s). This equates to 1,236 kilometers per hour (768 mph) or about one mile in five seconds. This figure for air (or any given gas) increases with gas temperature (equations are given below), but is nearly independent of pressure or density for a given gas. For different gases, the speed of sound is dependent on the mean molecular weight of the gas, and to a lesser extent upon the ways in which the molecules of the gas can store heat energy from compression (since sound in gases is a type of compression).

Although "the speed of sound" is commonly used to refer specifically to the speed of sound waves in air, the speed of sound can be measured in virtually any substance. Sound travels faster in liquids and non-porous solids than it does in air, traveling about 4.4 times faster in water than in air. - Wikipedia

Data only applies to dry air, with air being treated as a perfect gas.  See also Velocity of Sound in Various Materials.

 Temp°C 0m/s 1m/s 2m/s 3m/s 4m/s 5m/s 6m/s 7m/s 8m/s 9m/s 60 366.05 366.60 367.14 367.69 368.24 368.78 369.33 369.87 370.42 370.96 50 360.51 361.07 361.62 362.18 362.74 363.29 363.84 364.39 364.95 365.50 40 354.89 355.46 356.02 356.58 357.15 357.71 358.27 358.83 359.39 359.95 30 349.18 349.75 350.33 350.90 351.47 352.04 352.62 353.19 353.75 354.32 20 343.37 343.95 344.54 345.12 345.70 346.29 346.87 347.44 348.02 348.60 10 337.46 338.06 338.65 339.25 339.84 340.43 341.02 341.61 342.20 342.78 0 331.45 332.06 332.66 333.27 333.87 334.47 335.07 335.67 336.27 336.87 -10 325.33 324.71 324.09 323.47 322.84 322.22 321.60 320.97 320.34 319.72 -20 319.09 318.45 317.82 317.19 316.55 315.92 315.28 314.64 314.00 313.36 -30 312.72 312.08 311.43 310.78 310.14 309.49 308.84 308.19 307.53 306.88 -40 306.22 305.56 304.91 304.25 303.58 302.92 302.26 301.59 300.92 300.25 -50 299.58 298.91 298.24 297.56 296.89 296.21 295.53 294.85 294.16 293.48 -60 292.79 292.11 291.42 290.73 290.03 289.34 288.64 287.95 287.25 286.55 -70 285.84 285.14 284.43 283.73 283.02 282.30 281.59 280.88 280.16 279.44 -80 278.72 278.00 277.27 276.55 275.82 275.09 274.36 273.62 272.89 272.15 -90 271.41 270.67 269.92 269.18 268.43 267.68 266.93 266.17 265.42 264.66

Information from CRC Handbook of Chemistry and Physics, 51st Edition