Ah, fishing in the rain. You may not like the rain, but the fish love it! You may not believe it, but you may catch more fish while it is raining. It may not be exactly fun fishing in the rain at first, but after you get used to it and start reeling in those fish, you'll start liking it more and more. There are a few good logical reasons for this.
First, when it rains, the worms come out... and naturally, many of those worms along with other bugs get washed into the water. The fish know this and react by feeding. The underwater world erupts into a feeding frenzy, especially if it hasn't rained for a while.
Another reason is that oxygen levels rise from the rain hitting the water, which increases fish activity levels. There is so much oxygen in the water that it is easier for the fish to swim faster and longer without getting tired. When they see your nice tasty-looking lure, they're much more likely to go after it.
If you've ever been up on a high mountain, you know how much faster you lose your breath and get tired... that's because there's less oxygen up at the higher altitudes... come back down to sea-level, and you have more energy and can breathe easier. When it rains, for the fish, it is like coming down to sea-level after living high in the mountains.
A third reason has to do with what the fish can see (or maybe I should say "what they can't see"). Because of the clouds and all the ripples in the water, it is much more difficult for any fish to see you above the water. Believe it or not, under normal circumstances, fish can see you much better than you can ever see them. And when they do see you, more often than not, they're going to be gone in a heartbeat.
No matter how crazy and stormy it is on top of the water, everything is just about as calm underneath the surface of the water as it is on a normal day. So even though they aren't able to see out of the water as well, there is one thing that they can see just as well as any other time, and that's your bait!
There are quite a few reason's why fishing in the rain is probably better than fishing on a nice sunny day... and I am sure there are more reasons for this than what I have talked about. But the bottom line is that you'll probably catch more fish when it's raining... obviously, you might not catch as much, but experience has shown me that many times, fishing in the rain produces better results.
So, remember, next time you decide to go fishing and the weather reports call for rain, instead of canceling your trip, just smile, grab your rain gear, and get ready to have a great day of fishing... just remember, rain showers are fine, but don't waste a second scampering off the lake if you see lightning or hear thunder... not only do you put your life in danger, but it will spook the fish enough that they won't be feeding anymore anyways.