Agreed! Engine oil takes time to respond with the engine. Since the viscosity of the oil takes time to grade higher, it will depend upon the weather as well. If you are driving you car in a cold weather, then you may feel some junks at the first, but there is nothing to worry about , because engine oil takes time to enrol in the engine completely if the weather is cold. In a hot weather, the engine oil responds faster compared to other seasons. So just give it a day or two, it will be fine.