Rainy day at the feeders

Why do birds flock (pardon the pun) to feeders when the weather is miserable? Whether it's rain or snow, we are almost guaranteed to have visitors at the feeders when we have precipitation. We've had many visitors today, this Purple Finch was at the feeders about just before noon. As you can see, male Purple Finches are not purple - more of a raspberry colour.
Here's a view of our weather...