You would expect that St. Paul will be colder in the winter.
This is because St. Paul, being landlocked and situated away from the moderating effects of the ocean, tends to experience more extreme temperature variations, leading to colder winter temperatures. In contrast, Salem, being near the Pacific Ocean, benefits from the ocean's moderating influence, which helps to keep winter temperatures milder.
In summer, St. Paul may get warm as well, but the question specifically concerns winter temperatures.