Why does increasing temperature generally increase the rate of a chemical reaction?

If the temperature is increased: the reactant particles move more quickly. More particles have the activation energy or greater. The particles collide more often, and more of the collisions result in a reaction.

As you increase the temperature the rate of reaction increases. As a rough approximation, for many reactions happening at around room temperature, the rate of reaction doubles for every 10°C rise in temperature.

So the rate of reaction increases as we increase the temperature.