By reducing your speed you have a larger contact patch, more traction and the tyre's tread channels more water out from under your tyres. Be aware of other road users such as pedestrians, cyclists and motorcycles. The first thing to do on wet roads is to slow down and reduce the risk of hydroplaning. Hydroplaning occurs when you travel so fast that the tyre is literally riding on the water and not the road surface. As your car slows, your tyres will come back into contact with the road and the steering feel will return.
Roads are most slippery right after the rain starts.
The combination of oil, dirt and sand make roads slick until it washes away. So exercise extreme caution. Remember that no matter how good your tyres are, water on the road acts as a lubricant and increases the distance required for stopping. Watch out for other motorists. What is a safe speed for you could be a very dangerous speed for the car next to you with worn tyres.