How to Hive packaged bee in the rain:
Place an empty deep body over the ten frame brood box that has at least one frame feeder in it--full, thats 9+1. Remove the queen cage, pop the cork, and place midway between the feeder and the middle frames. Place two slats across the frames (use those unused entrance bars) and place the opened package upside down on the slats. No shaking. put on inner and outer tops and return when the weathers better or 5-7 days and it's done. The bees will take it from there.
I use a Nuc box mounted on a magritory top with a 4" hole in the top for this and feeding and a few other things. I haven't shaken bees into a hive in over 30 years and have hived packaged bees in nearly every kind of weather except hurricanes, blizzards, and tornados.