'Wet' snow vs. 'dry' snow. The size and make up of a snowflake depends on how many ice crystals group together and this will be determined by air temperatures. Snowflakes that fall through dry, cool air will be small, powdery snowflakes that don't stick together.
What is calibration? Calibration is the activity of checking, by comparison with a standard, the accuracy of a measuring instrument of any type. It may also include adjustment of the instrument to bring it into alignment with the standard.
1 1. INTRODUCTION TO STOPWATCH AND TIMER CALIBRATIONS This document is a recommended practice guide for stopwatch and timer calibrations. It discusses the types of stopwatches and timers that require calibration, their specifications and tolerances, and the methods used to calibrate them.