As a former engineer and manager at Waymo I can say with the confidence and sincerity of firsthand experience that this is not the case. People at all levels of the company think deeply about how different locations have present different challenges, including different weather.

Also it's not like we never have flooded roads here in the valley.

Whatever is going on, I'm confident it's not a result of straightforward parochialism in the way that you say you're comfortable assuming.