... but not as great as it is farther north.  

For example at latitude 80 degrees north (for instance Spitzbergen), the sun is out of sight for 4,5 months in the winter, but in the summer, it stays above the horizon for 4 months. 

In midsummer, Finland gets a lot of radiation energy - even a bit more than equatorial regions - because we have so long days in summer.
 

The amount of ultraviolet radiation is nowadays quite big because the ozone laye winter when only a small amount of radiation reaches the north.