The aim will be to see how the vehicle's sensor suite -- which includes lidar, cameras and radar -- hold out during Florida's hurricane season. "Heavy rain can create a lot of noise for our sensors. Wet roads also may result in other road users behaving differently. Testing allows us to understand the unique driving conditions, and get a better handle on how rain affects our own vehicle movements, too," wrote Waymo in a blog post.

Waymo will be testing the cars for several weeks in a closed course in Naples. Human drivers will then test the vehicles on public roads in Miami. The vehicles will then take to the highways between Orlando, Tampa, Fort Myers and Miami.

The whims of Mother Nature pose an obstacle for all self-driving cars. A study from Michigan State University found that even light rain can confuse the algorithms that self-driving systems use to detect pedestrians and other road users. Self-driving vehicles still don't know how to adjust to slippery road conditions in the same ways that human drivers do, taking extra steps like braking well in advance. Bad weather isn't the only factor keeping self-driving cars from being ready for prime time. The Verge reported earlier this year that Waymo cars in Arizona are still confounded by crowded parking lots and unprotected left turns. Hopefully, more aggressive rounds of testing can help get these vehicles ready for the road.