What should the time entries in column 2 of MF1M-10 reference?

The time entries in column 2 of the MF1M-10 form should reference UTC time. This is because UTC (Coordinated Universal Time) serves as a standard reference for timekeeping in meteorology, ensuring consistency and accuracy when recording and sharing weather data across different regions and time zones. By using UTC, meteorologists can coordinate observations and forecasts without confusion that might arise from local time differences.

Local time and Greenwich Mean Time are less standardized for the purposes of meteorological observations, as they can vary significantly depending on geographic location and local daylight saving time practices. No specific time would not provide the necessary context for the observations recorded in the MF1M-10, making UTC the best choice for uniformity in meteorological reporting.