When do you think we'll get the last frost?!

Its all down to your own microclimate. On Saturday night there was a frost at the allotment, but not in my garden 2 miles away. So my french beans are hardening off nicely.

When I went to check my greenhouse in the morning there were frost flowers on it. My rain barrel had a nice layer of ice on it. But if all goes fine night temperatures should be improving later this week. Maybe i can even leave some seedlings out during the night. But not my precious tomatoes of course.

My delicate ones won't go out till the 1st of june.

A quick Google throws this up, but I've no idea how reliable it is:

NewSteve's map looks way too optimistic in general, and definitely so as far as Sheffield is concerned (already had a ground frost this May!)

It may be mapping air temperatures of 0C or below rather than the possibility of ground frosts in vulnerable areas at air temperatures as high as +4-5C, but the key doesn't make it clear which of those applies.

As has been stated elsewhere, particularly tender crops need conditions warmer than just frost-free.