I ride in the rain and have found a major benefit from changing lubes in the winter. My winter lube is less waxy and more viscous, It really stays almost fluid as opposed to the summer lube.
AND I clean and re-lube when the grit becomes palpable (usually about 3 rainy rides. I make every attempt to stay out of the cinders and dust garbage on the shoulders too.
Some soils are red. Is the dust and color of the soil in your area red. After all red soil is iron oxide too!