At least for a lone paddler it is really important to have a paddle float and to actually know how to use it to climb back into the kayak. A paddle float can be made of closed cell foam, but usually it is inflatable. And in emergency situation, you could probably make one from your life jacket, although undressing it is generally not a good idea.
Note that if the weather is rough, climbing back into the kayak is a task even if you know the tricks. And if you have not practised at all, your changes of succeeding would be slim even in calm weather. There are some variations to the paddle float re-entry, but we will learn the one that works well on all kayaks.
If the weather is windy get to the upwind side of the kayak so that your legs will not go under the kayak when the wind pushes it.
Take your paddle float, put a little bit of air into it and secure it onto your paddle blade. Then fill the float until it is full.
– you also need to flip your kayak back upright and try to remove most of the water from the cockpit. See more at tutorial Emptying Kayak by Self.
Place the other paddle blade on to the rear deck of your kayak right behind the cockpit coaming. Some people say it is a good idea to secure the paddle under the deck ropes, but it could make things difficult later. Therefore you should first try to do the re-entry without securing the paddle, and only if it fails, use the ropes to make a fixed floating support.
Stay at the stern side, so that the paddle is between you and the cockpit. Grab the paddle and the cockpit coaming and place your arm over the paddle. Grab your other hand to deck ropes or what ever that gives you a good grip. Check that the paddle and kayak are in 90 degrees angle to each other and sort of forms a letter T, if looked from up. This way the paddle will give you the best possible support.
Jump up and pull your upper body to the rear deck. Quickly raise your other leg and hook it over the paddle. Then raise also the other leg over the paddle and try to keep the paddle and kayak in 90 degrees angle.
Slide your body more onto the rear deck while keeping your weight slightly on the paddle floats side. Move your other leg into the cockpit. Check again that the paddle and kayak are roughly in 90 degrees angle.
Move the other hand to the paddle, hold tightly and swing also your other leg into the cockpit. If there are waves, be prepared to lean quite intensely to the paddle float.
Flip your self back to sitting position and remember to keep the balance slightly on the paddle floats side.
After you are successfully got back in, you can swing the paddle to your front side, but don't remove the paddle float yet. Try to empty the kayak from remaining water and secure the spray skirt while using the paddle float as a support.
– In bad weather, climbing back to your kayak can be a difficult task. If you know how to do an eskimo roll, but have failed for some reason, a good idea might be to try doing a re-entry and roll with extra support from paddle float.