To blow in means
A) to be carried towards you in the air
Example sentence:
- A cool breeze is blew in from the lake.
B) for windows to be broken and the peaces fall inside the building
- The hurricane would blow in most of the windows if it weren't for the hurricane shutters.
C) to arrive unexpectedly (informal use) for a visit
- It's ok to blow in for a visit as long as you're not expecting to be catered to.
A question about C for the native speakers. How common is it in your country? It's not part of my active vocabulary possibly because I haven't heard or seen it used at least for a long time. I hear about 1-2 hours of English spoken every day and not any particular local variant.