Pea seedlings can withstand temperatures of about 28F. They can handle as low as 20F with some potential damage. I have been able to get my peas through a cold snap by covering them with a layer of straw.
Spinach is one of the most cold hardy vegetables and can even be overwintered in many locations with good luck. This cool weather crop can withstand temperatures of 15F!
This cool weather crop will germinate in soil temperatures as low as 45. And once growing, the plants can withstand a cold frost.
Cabbage is a member of the brassica family and thrives in cool weather. You can start planting out as early as 4 weeks before your last frost date. Cabbages can handle freezing temperatures down to about 20F.
Broccoli is another member of the brassica family which loves the cold. Like cabbage, start your broccoli seeds indoors and transplant to the garden about 4 weeks before your last frost.