How rubbish is the weather? Sometimes you just have to find a gap in the weather get on with it. It is a bit drizzly here but I would still get on with it due to it still being humid and warm. Just don't hang about. Torrential rain is a different matter. Also, I would have thought it better to have performed a split previously, allow to raise emergency queen cells that you knock down, and then order a queen to put in a hopelessly queenless split. It may be a little early to introduce the queen if you haven't done this. I would have let the split raise their own queen and replace at a later date if needed