Rain brings changes to the road surface and your visibility, so you need to adjust your riding technique and watch your speed.
The process of checking the road ahead and around you is called scanning. It’s how you will become aware of potentially dangerous situations up ahead so that you can react in time. Because new dangers present themselves in wet weather (standing water, manhole covers, etc), these should be in your sights.
Your foot pegs and brake pedal, especially if slightly worn, can become more slippery in wet weather. Some boots are worse that others. Try to keep your palms dry, too.
You should be wearing decent wet weather clothing so that you don’t get cold and uncomfortable. You visor can fog up in some conditions; you can use an anti-fogging product, or keep it open slightly. Being uncomfortable while riding makes riding more tiring, and also it can be distracting. If you are really uncomfortable then you might push on faster than is safe just to end the journey. If you get really wet then you can be at risk of getting really cold due to the wind chill.
Spray and visibility
If there is a lot of standing water and you are driving among other vehicles, especially large vehicle, spray can become an issue both in terms of you seeing out of your visor and other motorists seeing you. Choose your road position carefully so that you don’t ride in spray. This could mean dropping back further from the vehicle in front. Approaching heavy vehicles can kick up blinding spray onto your visor.
If it’s raining it is likely to be darker because it will be overcast. A high-visibility jacket is advised.
If the sun has come out after rain, glare from wet tarmac can be blinding.
Water decreases the available friction on the road’s surface, particularly just after it has rained after a long period of dryness. Deeper standing water can cause aquaplaning/hydroplaning when your wheel rides up on top of the water rather than disperse it, which is why you should ensure your tyre has enough tread on it.
Painted lines and metal covers will have much less grip.
It will be more easy to skid so make sure your braking is gentle and progressive. It’s also much easier to wheelspin – in wet weather you’ll get a slower and more progressive breakaway if you do overcook it with the throttle, but that doesn’t mean you’ll be able to catch the slide. Either of these scenarios could lead to a highside or lowside accident. If it’s really slippery, you shouldn’t be braking on your rear wheel if your clutch is in, and you’ll need to take care when changing down as extra engine braking could cause the rear wheel to lock up.
You will take longer to stop so increase your following distance to 4 seconds, and more if a vehicle behind you is tailgating you.
If it’s nighttime and wet it will be even more difficult for other drivers to judge how far you are from them, whether you are approaching towards them from a distance, or if you are riding alongside in their blind spot.