Before convincing ourselves, we must look at the risk of under-information; preliminary checks are only a starting point.
Even with the best information about the rainy season, weather conditions can change unexpectedly.
The mandate is to protect against unforeseen events, not just to inform, because last-minute weather can always disrupt plans.
For example, a traveler might check historical data and still end up with torrential rains due to an unforeseen climatic event, rendering their initial planning obsolete.