If you're looking for a dependable warm shoe cover this can do the job to around 35 degrees. The difference in reviewers comments might be because some wear summer highly breathable shoes with these covers while others are wearing shoes with a less breathable fabric. The difference I've experienced in midwestern windy and cold temps is the shoes. Feet will freeze in wind chill if I wear summer shoes even with these covers. Get warmer inserts (use your Ugg inserts if you're not racing or training) to keep the cold off the bottom of your feet. These covers aren't magical. They're built well enough to endure the season(s) without breaking down in any way but can't keep frigid air from eventually attacking your feet. The holes for your pedal and heel let the air through to chill the soles of your shoes. If you're riding in mild to no wind they're great. Windy? Better have some warmers.