Hunt the auroras: I mention this first as this was what brought me to the city for the first time. It was the September of 2021 when I saw news of a period of high solar activity that may bring in good auroras. Oulu is one of the southernmost locations in Finland with frequent auroras. Unfortunately, the weekend we travelled to Oulu was cloudy and we got no show. However, it was during another trip later that year, I finally managed to see the aurora in Oulu. The Facebook group Oulu Aurora Spotters has a map that tells the best locations in Oulu to see auroras. The group also has active members who post about aurora sightings almost immediately.
Winter cycling: Oulu is the winter cycling capital of the world and home to the Winter Cycling Federation. It has the most extensive network of cycling routes in Finland covering the entire city and also the neighbouring municipalities. Not just that they have the routes, but most of them are well maintained and kept illuminated even through the cold dark winters which is basically about half the year. The real thrill of cycling does come when the temperatures go as low as -20°C.
Meet the Toripolliisi: Be it sun or snow, the policeman is on duty overseeing the Oulu's market square. The bronze statue sculpted by Kaarlo Mikkonen was unveiled in September 1987. It is dedicated to the market police officers who patrolled the area between 1934 and 1979. The Toripolliisi is probably the most recognisable and photographed landmark in the city. So don't forget to get yourself clicked with the officer.