It is more effective during a dry spell ::)
In this weather, you may need a few more applications. When digging make sure that you get out as much root as you can otherwise it can regenerate if the weedkiller hasn't thoroughly penetrated.
This rain will have softened the ground nicely, making digging easier (as long as its not waterlogged)
I've never tried this but in this weather it might work. Can you get hold of any clear plastic sheeting? if so, after the next application, cover the ground with the plastic, keeping off the rain and letting the Glyo do its thing.
Happy weeding ;)