I'm not questioning your logic here, but how do you keep intimate knowledge of the seasonal vagaries of shift changes at every department of your local hospital?
If you’ve been to that hospital you can easily take note. And most places have a shift change between 5-7am. This one is almost universal, as far as I have observed, even in different countries.
You can probably make a good guess, but at this point I wouldn't be surprised to find websites or Facebook groups dedicated to tracking this information for hospitals in any given area.
