Honestly you can catch on a crawler in 32degree water. Why would a walleye care about water temp in relation to a worm? It is about speed and action. I am in no hurry to break out the worms and spinners. cranks usually catch the biggest anyways. Worms can sometimes catch the most but not always. If I can catch on cranks I will not bother with the expense, mess, hassle, trash fish issues etc with the spinners.