Morningfox is right about "the heat is spread over a large area". And to give you an idea, hold a flashlight and shine it against a wall in the dark. Stay at about half a meter away from the wall. Hold the flashlight horizontally to the ground. You will see a circular spotlight on the wall. Now, bend your wrist a little upwards. You will see the spotlight taking a new shape of an "oval" (elongated circle), and not a perfect circle anymore. What will this say? The amount of light (in this case heat from the sun) that was hitting the wall first is the same as the amount of heat it is hitting the wall now. BUT...the area is somewhat larger. This means, like during the winter in any place on the globe, the temperature is spread to a larger zone thus decreasing the heat you get on the surface where you are per same unit of area. And don't forget that the rays of the sun, at this extreme angle at the poles, will pass through more atmosphere than anywhere else, hence with more dispersion of the temperature before it reaches the soil.