> Seattle/Vancouver are so far up north that in December, the sun rises at 10 AM, and it starts getting dark at around 3 PM
That's a bit of an exaggeration. Even on the shortest day of the year in Vancouver, the sun rises at shortly after 8am and sets just after 4pm, which is a full 3 hours more of sunlight than you're giving it credit for.
Yes, if you want to be pedantic, and you define sunrise as the "bottom of the sun" touching the horizon -- as a meteorologist would -- instead of the much more practical definition of the sun is "sufficiently above the horizon for it to no longer be dark outside."
I came in to work at 10 AM every day, and that's when it would start getting light outside (9 AM, still dark out).
Then, I struck a deal with my boss to work later and run my daily 5 kilometers midday at 2:00-2:30 PM instead of after work because by 3 PM, it would be too dark outside to feel safe from cars while exercising.
That's a bit of an exaggeration. Even on the shortest day of the year in Vancouver, the sun rises at shortly after 8am and sets just after 4pm, which is a full 3 hours more of sunlight than you're giving it credit for.