details show TAT/OAT
Temperature rise is mach dependent. At low MN, characteristic of many of the WW2 bombers, it wasn't really a major concern. If it were, the equations were known and the answers could be obtained easily via the prayer wheel assuming a mod to model the particular equation. For example, on the CR, you have the temperature rise in one of the Huber scales. Alternatively, it would have been easy enough to provide some paper tables to achieve the same end.
Current jet traffic is well and truly fast enough for the rise to be noticeable.