Against my better judgment, I saw a quick opportunity to go fishing in late December. The weather had warmed up and was pushing 50 degrees, so I figured it would not be tooooo miserable out there. Besides, even if I could just do a recon in anticipation of fairer weather, I would be a winner for the day.
Once I made the decision to go, I had to decide how to dress. We all know that layers are the ticket, and I remember a miserable month in the Army in Alaska in winter that confirmed that wisdom. The additional challenge is that when fishing, you may be stationary in very cold water for extended periods of time. After all, casting does not generate a lot of body heat. Finally, you do not want to wear too many layers as that will inhibit your ability to both walk and cast.
In the "olden days", we used hand warmers to solve this problem. These were small appliances that would burn lighter fluid to generate heat. The issue with these is that they are a hassle to light, you have to find some lighter fluid and the heat level is hard to control. They also are bulky - which pretty much limits you to using only one.
Thankfully, technology has come to the rescue. You can buy chemical heat packs like the one shown below at any Walmart or sporting goods store. The heater is activated by exposure to air. All you do is break the seal, shake and then put in a pocket. In a few minutes time, you will feel a nice warm glow of heat. They are small enough and cheap enough that you can use multiple packs to match your exposure to the cold.
In fact, you should put some of these in your car in case you break down on a cold road!