What weatherproofing rating do I need for an outdoor smart plug?

Look for an IP-rated enclosure: IP64 (dust-tight, splash-resistant) covers most covered-patio uses, while IP65 adds protection against low-pressure water jets for more exposed installs. Several picks here, including the Kasa EP40 (IP64) and TP-Link Tapo P400M (IP65), publish these ratings; verify the temperature range too if you run holiday lights in freezing weather.