Distribution of Flight Rules

I took a quick look at the distribution of flight rules today, focusing on Part 139 airports in the lower 48 (CONUS). Not surprisingly, most airports are VFR or MVFR, making up more than 97% of all flight rules. IFR airports made up 2.23% of the sample. Note that this is just one observation! Currently, the weather in the CONUS is pretty good, with only 3% of Part 139 airports reporting rain, and 22% reporting broken or overcast ceilings.