The combination of both too cool and too wet, will often rot corms that have no roots. If they are going to rot it will be when first planted, if they have roots developed before the excess water and cold soil are evident they usually will go through it with no problem. Al

Al is right.

If you can, don't soak them. Plant them into individual pots using damp mix combined with grit and place them in a warm area to sprout. Unless the mix dries out, don't water, or only lightly water, and keep them well-drained.

Ensure they 'grow up' in good sunlight otherwise they'll be leggy and floppy.

Or plant directly into the ground that you've 'pre-warmed' by using a cloche or grow-tunnel over the area for a few weeks before hand.

Good luck with the next batch (though you might not have enough growing time left before the heat signals 'it's time to go dormant' for them.)