The Northern Gardener Magazine still exists as I recently received the January/February 2022 publication.  The magazine is a bi-monthly benefit of the Minnesota State Horticultural Society.  For information on the types of membership, costs of each, and joining or renewing your membership click here: Northern Gardener Membership Benefits.  Note the digital membership does not include a copy of the magazine.  If you believe you have an existing membership you may want to contact the organization to find out your status by calling<personal data hidden>.  
Winter is a great time to spend curled up with a good gardening book or magazine.