We are currently in Oslo (January 2025) and finding walking in the city a bit difficult because most of the sidewalks are extremely icy. We are from the U.S (St. Louis area) where ice in winter is a normal thing and we are still having trouble. So wear shoes with good treads (my husband’s hiking boots are surprisingly slick, while my tennis shoes are a bit more stable) and be very mindful. Good luck and be safe!
Added note: at the time of our visit, the streets in Oslo are pretty clear. Driving shouldn’t pose a problem to those familiar with winter driving. It’s the sidewalks that are a bit dicey.