In terms of precipitation, rainfall in Oulu ranges from 0.4 - 2.4 inches per month. August is typically the wettest month, when rainfall can reach 2.4 in. April is typically the driest time to visit Oulu when rainfall is around 0.4 in.
If weather is an important factor for your trip to Oulu, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 60.8 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 14.0 F).