In southern California, you don't really need a rain gauge because it always reads...ZERO! Still, it's a "nice to have" to geek out in the garden, and when I say "geek out" in the garden, I mean this toy is for serious gardening freaks, like my Mom.

The Honeywell TC150 Alarm Clock and Wireless Rain Gauge displays the rainfall, has a programmable rain "alarm," and stores up to 7 days of rain history. Not only does it "do rain," but it also has a quartz clock with an alarm (not sure for what you need an alarm on a garden clock, but ...), and humidity monitoring.

Like I said, gardening geek.