Mild-temperature cycling pants (rated for 10-20°C / 50-68°F) fill the gap between summer shorts and winter tights. They use slightly heavier fabric or come in a 3/4-length "knicker" style that covers your knees, providing just enough warmth for chilly morning starts and shoulder-season rides without overheating you once you're warmed up.
They're especially useful for spring and fall conditions when temperatures fluctuate during a ride—starting cool but warming up later. The extra coverage over your knees also helps protect your joints from cold air, which can feel stiff and uncomfortable even at moderate temperatures.
Keep in mind that mild-temp pants can feel too warm above 22°C (72°F), so they're not ideal for warmer days. But if you regularly ride in variable shoulder-season weather, they're a versatile addition that can extend your riding season comfortably.