I mean, maybe a few showers but I'm willing to bet that it still doesn't amount to much. Maybe ~0.1-0.25" of rainfall over the next week unless you find yourself under a brief convective downpour.
A whole lot of complaining over a tenth of inch of rain that you have no control over but to each their own!
I would say that the market is already correcting based on those charts. Do you know how big of a lag is there between the listing price monitors/your charts above and the official home price surveys/indexes? I assume the official ones have to wait for closing + some amount of time to actually show up in the local govt database.
He might not be happy with the outcome of the next few days though afterwards. Instead of one big rain event and nice weather afterwards it’s a week of on and off rain showers which I’m willing to bet he probably likes even less.