So the Bay Area is incredibly mountainous for such a densely populated place. There are numerous 1000 meter peaks ringing the bay, and even more only-slightly-lower peaks and ridges that are right in some of the towns in question. When you combine this with the ocean and a huge estuary that drains most of the water in California out through a small channel, you get very dynamic, very localized weather patterns. There are lots of places in the bay area where moving a few blocks produces significant changes in climate.
There's an narrow altitude band in the Berkeley and Oakland hills where a nearly constant temperature inversion creates a literal "banana belt" (you can actually grow bananas). 100ft lower or higher, you get frosts and can't.
There are places in Woodside with two adjacent houses, one of which is in dense fog nearly every afternoon and the other never is, because there's only a small channel in the ridge that allows the fog to spill in, and it drains nearly straight downhill.
If you get lucky in January, you can hike Black Mountain in Los Altos and go from 75 degrees at the base to a couple inches of snow at the top.
Anyone who's lived in San Francisco can tell you all about the numerous bizarre little micro-climates from neighborhood to neighborhood. They can be exceedingly different, and it's not unusual for the temperature to drop 15 degrees as you cross the city from east to west.
So yes, Redwood City is two towns over from Palo Alto, but two towns can mean vast differences in an area where the weather changes drastically when you go around the block.