Posted: 25/11/2017 at 15:35
Frost doesn't affect crocus - they come from all sorts of habitats including alpine conditions, so don't worry about that affecting growth, or the flowers
As Philippa says - where you are and what your own climactic conditions are like will dictate a lot in the garden. Everything I grow will be several weeks later than where you are on the south coast, but even here, crocus will start poking through in December.
Most crocus flower from around February, but different varieties will cause a variation. If it's milder just now, lots of bulbs will have foliage growing, but as the temps get lower, most of those will slow down. I'm not a fan of these mixed plantings in pots, because you can end up with a lot of foliage from the previous flowering bulb obscuring the emerging flowers of the next one. You have to be quite careful about how you layer them, and usually two or three types is the maximum to ensure a decent display.
Take photos through the flowering time, and see whcih bulbs are successful for you, and then you can always alter your plan next year to give the best display for your requirements. Be objective if you can, or ask someone else to give an opinion