Jeff Bezos, Lauren Sanchez Caught in Rain, Thunderstorms at Pre-Wedding Bash

Jeff Bezos and Lauren Sanchez made it crystal clear no grumpy locals were gonna rain on their parade ... but Mother Nature had other plans, literally soaking them before their big "I do."

Catch the clip ... Jeff and Lauren got hit with a serious downpour after their Italian rehearsal dinner bash Thursday -- the billionaire holding onto his bride-to-be with one hand and sporting an umbrella in the other as they scrambled to a water taxi.

There were a bunch of security guards hovering to make sure the soggy dash went off without a hitch -- but all good, Jeff and Lauren looked totally chill as they kept the party going.

Other videos from the area show lightning ripping across the night sky as Jeff and Lauren kept busy with their ultra-luxe festivities -- and it's unclear how much the storm wreaked havoc on their plans.

Luckily for them, the worst of the storm has passed -- and the forecast’s lookin' fab for days ahead.