What does 0w20 mean for engine oil?

[VonHaley]

0W-20 is the viscosity grade of engine oil. Here is some introduction about automotive engine oil: 1. Engine oils are specifically classified into 4 types for summer use, 6 types for winter use, and 16 types for all-season use. 2. The summer oil grades are: 20, 30, 40, 50. The larger the number, the higher the viscosity and the higher the maximum applicable temperature. The winter oil grades are: 0W, 5W, 10W, 15W, 20W, 25W. 3. The letter W stands for Winter. The smaller the number before W, the lower the low-temperature viscosity, the better the low-temperature fluidity, and the lower the minimum applicable temperature. 4. All-season oils have the following grades: 5W-20, 5W-30, 5W-40, 5W-50, 10W-20, 10W-30, 10W-40, 10W-50, 15W-20, 15W-30, 15W-40, 15W-50, 20W-20, 20W-30, 20W-40, 20W-50. The smaller the number representing the winter part, and the larger the number representing the summer part, the higher the viscosity and the wider the applicable temperature range.