The only worm I've ever seen in mid winter at the surface and active are redworms. They are also called manure worms and red wigglers, but they really dont wiggle once you've held an Alabama Jumper. During the summer they are deep under ground doing hibernation. Once it gets cold and we've had a first frost the redworm has its action time. I kick any pile of horse manure in the pasture and there are redworms swarming inside, even when snow surrounds the horse manure. But once it gets 85° Fahrenheit they are gone. I am with the others, the red worm ( manure worm, red wiggler) is the only really cold hardy one. During late spring nightcrawlers come up to breed right on the surface. You can see them stuck together by the head rings with their tales still in their tunnel in the ground. This happens on the rare nights when things are just right. Old timers used to know when the nightcrawlers mated by the signs. During the cool wet mating nights you can snatch up bucket fulls of them. I saw it happening last May 15 2026. Nightcrawlers never go into horse manure. No earthworms do except the red worms. During summer since at least the 1800s the Alabama Jumpers are the hot weather summer earthworms. They are the best fish bait because they are firm bodied to hold on a hook and wiggle better to entice fish to bite. They can be found at the surface under piles of tree leaves in the woods all over the southest usa. I used to sell them for bait in 1970 in Pensacola, and my grandpa in 1920s in Galveston. They wont survive cold so dont even think about them, theyve had 200 years to prove that. Now the news changed their name to Asian for sensationalism and fearmongering. You wont find an all around ,all season earthworm. They each have their own seasons. There is two species of NATIVE Alaskan earthworms you might look into but I have zero experience with these two. I bet they are hardy as they obviously survived ice ages up there on the arctic circle. Everyone seems to agree Red Worms for the win! The redworms are small but they are your cold hardy earthworms. I am in usda zone 7b and we get around 0° Fahrenheit but the winter red worms dont even notice.