Molecules move more slowly in cool air than in warm air.
They still travel randomly and they still collide with each other, but the impact of their collisions is not so great because they are moving slowly.
Because the impact of collision is minimal, the molecules don’t travel far (in fact, the atmosphere contracts in cold air), and have more of a chance of running into each other.
The frequency of their collisions is much greater than that of warm-air molecules. Since air pressure is determined primarily by the frequency of contact, rather than the force of contact, cold air produces high air pressure.
Slow-moving, low-impact, frequently colliding molecules = cool, high air pressure.