You’re a bee with a personal hive, Richard!
I took a slightly different approach and looked at a fairly large sample of observing nights from a dark site (i.e. not at home) in February vs. total nights under a dark sky. That came out to 41/622 = 6.6%, compared to 7.7% of the days of the year that occur in February – not a large difference. But that includes two February trips I made to Costa Rica (4 nights) and Texas (4 nights). If I throw those two months out, I’m left with 33/571 = 5.8%, which sounds pretty similar to the figure you came up with. In other words, February is a below average month due to the weather conditions, but there’s still plenty of observing done.
Steve