If the weather's not playing nicely, why not head to Parque Bicentenario Guanajuato? You'll be fascinated by just how much you can uncover about days gone by here.
This Silao collection of historical artifacts is an interesting place to kick off your day of sightseeing. There's plenty to explore in the vicinity, including Guanajuato Bicentennial Park, Silao Main Square, and Church of Santiago Apostol. Take your time at Parque Bicentenario Guanajuato before making tracks to these other fine attractions.