For most motorcycle riders the first time riding in the rain is normally not intentional. They take off on an all day ride when the sun is shining and by afternoon they realize they're going to get their first taste of wet asphalt, like it or not.
Riding a motorcycle in the rain has a natural progression for some riders. Many never ride in the rain the first year they're up on two wheels. They're timid about it the second year, feeling more confident by the third, and by the fourth year they're asking the question - "What Rain?"
Whether you get caught in an unexpected rain, of you are an experienced motorcycle rain rider going out in spite of the rain, there are a few things you should remember, and watch out for. Of course you need to follow the common sense rules whenever you are on a wet road; slow down, leave more space between you and the vehicle in front of you, allow yourself more time to stop, and take turns much slower.
Here's a list of critical rain hazards to watch for whether its your first time riding in the rain, or you ride your motorcycle in the rain often.
Painted Lines - Crosswalks can be slippery and unsafe for motorcyclists, particularly if you're turning and crossing the lines at an angle. Slow down more than usual and try to keep a constant speed - slowing or accelerating can cause the rear tire to break loose.
Lane Dividers can be dangerous in wet conditions. The biggest issue is when you are switching lanes to pass someone. Accelerating while crossing a lane divider can cause the rear tire to break loose, so cross the lane divider at a constant speed and then accelerate once in the new lane.
Diamonds in the HOV lanes. These can be very nasty when you lean into one. The diamond is shaped so you will just slide across it and continue to slide along it. Howerver you should not be riding in the center of the lane anyway, especially if it is wet.
Any painted line or surface is a hazard, and until the DOT addresses the issue and comes up with a less slippery texture, you're the one in control of your destiny.
Surface Textures - Many commercial and residential parking areas are paved with very slick concrete surfaces. Your wet entry into the gas station, local mall or condo complex can put you on the ground in a second. Again, ride slow and straight up and don't let the concrete bite you. The area around gas pumps is notoriously slippery from people spliiling gas and oil. Be sure to appraoch and leave the gas pumps very cautiously.
Rubber - How about that rubber they use around railroad tracks to decrease the sound as cars drive over them? Forget those little circles on the surface, these provide zero traction to you as you cross. Slow and straight up.
Steel - Manhole covers are enemy number one and railroad tracks rank a close second. Making a turn over the surface of them sets you up for trouble. Avoid them whenever possible, or keep the bike straight up and cross over them slowly.
Railroad tracks have a way of popping up on you just after a turn and you may still be into a lean when you reach them. Look for the crossing signs ahead of time, slow down and stay straight up when crossing.
Grated bridge crossings and metal plates are a nasty encounter in the rain. Look at where you want to ride, take it slow and don't try anything fancy, particularly a lane change.
Standing Water - Puddles/Pot Holes - It only takes one time to know how this one feels. You cruise through a puddle and after it's too late you realize you just went into a pot hole that wants to flip your bike. Or the puddle is deeper then you thought and hitting it at a fast speed can put enough resistance on your front tire to lift your back tire off the ground. Avoid puddles if you can, if you must ride through them...slow down and keep you bike straight up.
Oil - It's everywhere and very very hard to spot in advance. Try to ride in the car tire tracks on the left or right side of your lane. The center of the lane naturally has more oil and dirt. Those little red and blue rainbows on the ground mean danger. Ride slow and straight up. Remember the first rain after a dry spell is always the most dangerous. If you're caught in the first rain following a dry spell remember the roads are covered with lots of oil and dirt that will be lifted from the surface in the first 30-60 minutes of a new rain.
Lane Position - Avoid riding in the center of the lane, this is where most of the oil will be. Also avoid riding on the right side of the right-most lane, this is where you are most likely to encounter puddles and/or pot holes.
Tires - If you thought you might save some money by buying long lasting tires, think again. Such tires are typically not as tacky and have less traction when the rain comes out. If you find yourself riding in the rain often, look for more tacky tires with a tread pattern designed for wet roads.
Rain Gear - If there is even the slightest possibility of rain, bring your rain gear. Rain gear not only keeps you and your clothes dry, it can actually make you a better rider in the rain. If you are riding cold and wet, you will naturally tense up lessening the control you have over your motorcycle. There are many types of motorcycle rain gear out there and it is recommend that if you will be doing a lot of motorcycle riding in the rain to buy quality rain gear.
Note from the writer: I find the more rain gear you carry, the less chance of encountering rain :-)
Remember when riding in the rain, or in the best of conditions, a near disaster (such as sliding in a turn, or hitting a major pot-hole) will throw you off your game. Even after you recover safely, your nerves are shaken and you are out of sync with your bike. A good idea is to find a safe place to pull over, take a deep breath, and calm yourself before going on.