Engine oil for lawnmowers is recommended based on the average outdoor temperature at the time of use. Colder temperatures turn the oil viscous. For non-freezing weather where the temperature rarely falls below 40 degrees Fahrenheit, SAE 30 or 10W-30 oil is recommended. For colder temperatures, 5W-30 is recommended.Continue Reading
Another consideration is synthetic oil, which is more expensive but offers the best protection and tolerance for temperature variance. Synthetic 5W-30 is recommended for temperatures varying from -20 F to 120 F.
Even though it is initially more expensive, synthetic 5W-30 is the best choice, primarily due to longer life and because there is no need to change oil due to temperature.Learn more about Outdoor