Speed is speed. Doesn't matter whether it's average, peak, minimum, or instantneous.
(Any unit of length or distance)/(any unit of time) is a fine unit of speed.
A few of the more popular ones include
speed =distance/speed .units to express speed are m/s and km/hr.
metre
Any speed is distance covered/time to cover the distance .Whenever you calculate a speed using this definition, the answer you getis the average speed during the time it took to cover the distance.The same units are used to describe any speed, whether it's average orinstantaneous speed.(any unit of length)/(any unit of time) is a perfectly good unit of speed.
joules
You can express or determine the speed of wind using the Beaufort Wind Scale.
tanga
liter and cubic centimeter
liter and cubic centimeter
cubic or cubed
The most common units used to express the volume of gas are liters (L) and cubic meters (m³). Other units such as milliliters (mL) and cubic centimeters (cm³) are also used for smaller volumes.
nanometers
It is usually meters per second. But it can vary if that is not a suitable unit to use.