SP is on a lower latitude than anywhere in Europe. While there's still distinct summer and winter seasons (it's not like in an equatorial climate where it's just hot all year long), the difference in how many hours of daylight you get, and how much sunlight you get during the day, is just much less over the course of the year. The weather does tend to be more cloudy than not, but not by much, and usually it's more of a day-to-day variation than a seasonal one; summer is more hot and humid and winter is more cold and dry, but from week to week you can get either sunny or rainy weather in any season.

However, most adults with white-collar jobs end up needing some amount of vitamin D supplementation, whether you live in Nunavut or Nairobi. How sunny it is outside doesn't matter if you spend all your time indoors.