Mid-latitude continental interiors have greater extremes in temperature than coastal areas because large areas heat up and cool off more quickly than oceans. Therefore, in the winter, the interiors of continents will be much colder than along the coast. Similarly, in the summer, the interiors heat up much more than the coastal areas. The colder winter temperatures and warmer summer temperatures of the interior result in a greater range of temperature. Oceans provide both cold and warm currents.
Oceans moderate air temperatures rather than causing extremes. The Intertropical Convergence Zone does not move far enough north or south to reach the mid-latitudes. Coastal storms can and do cause much damage, but the extremes of temperature are still greater in the interior. I hope this will help you, also, continental climates are further away from the equator:)