Yes the demand goes way down during a heavy thunderstorm, however there are always some who will expect to use the monrails during a storm. As for the shutdowns in my experience they were almost always due to lightning causing power outages.You mean when it's pouring rain and nearby thunderstrikes, there *isn't* a huge demand for for people to walk to train stations or hang out under tiny bus ports to use the transportation system?!!
On a side note those heavy storms were my absolute favorite times to drive! There’s nothing quite like driving a train at 40 mph while you literally can’t see anything at all.