From the equality of the flow parameters on two different days  , measured values on one day can be corrected to those that would be measured on a standard day so,
     where  are measured values and 519 degR and 14.7lb/sq in are the standard day temperature and pressure.
The temperature and pressure correction factors are  and , so     
For speed the corrected value is     
Example: An engine is running at 100% speed and 107 lb of air is entering the compressor every second, and the day conditions are 14.5 psia and 30 deg F (490 deg R).
On a standard day the airflow would be  which is 105.2 lb/sec. The speed would be  which is 103%. These corrected values are what would appear on the compressor map for this particular engine.
This example shows that a compressor runs aerodynamically faster on a cold day and would be slower on a hot day. Since the day conditions are those at entry to the compressor an extremely hot day is produced artificially by the ram temperature rise at high Mach numbers. The aerodynamic speed is low enough, despite the engine running at its 100% rated mechanical speed, to get into the rotating stall region on the map so an engine operating at these Mach numbers needs the appropriate features. The General Electric J93 had variable inlet guide vanes and stators. The Pratt & Whitney J58 had inter-stage bleed from the compressor and 2-position inlet guide vanes. The Tumansky R-15 had pre-compressor cooling to reduce the air temperature and avoid low corrected speeds.