The chances of lambs freezing are severely reduced. That's not to imply that adverse weather won't occur during the spring, it does, but the extreme cold is less likely to occur. Spring lambing has an advantage in that the breeding and lambing seasons are shorter and more condensed. Breeding ewes in late October through early December ensures that all ewes of any merit are fertile. Rams are also more fertile in this time period.
Spring lambing can also offer more management flexibility.
Leaving some wool on the ewes for the winter period allows for outside wintering on crop residues, pasture overgrowth or poorer quality hay. Using large round bales can decrease labor and cost of winter feeding. Ewes can be lambed inside barns as with winter lambing programs or with the right type of ewe, they can be lambed on pasture. Ewes and lambs can be kept in mixing pens around barns or can be moved to pasture shortly after birth. Lambs can be raised on grass with their mothers, offered creep grazing or offered creep feed.