"across the street..., through the rain..., what logo?"
"the less likely that it will be instantly recognizable, through the rain, on the other side of the street, when you can???t read the words accompanying it."
You are less likely to see the 2-colors (or rather 1 color, and negative space) than if through the rain and across the street you may not even be able to see the shape, but you have a better chance of seeing something red in one corner, yellow in the opposite, blue in another corner and green in the last and recognize that as possibly the Windows (or Chrome, but that's another matter).
You actually have to have the logo WITH the words to tell it is Windows and not some European flag or something so this statement is completely unrealistic.