Knee warmers cover the knee and part of the thigh and end just below the kneecap. They are the smallest option and made for exactly the temperatures where leg warmers would be too warm and bare knees too cold.
When knee warmers are the right choice
The rule of thumb among cyclists is: below 18°C, cover the knees. In exactly this range, between about 12 and 18°C, knee warmers show their strength. The knee joint gets little blood flow and cools quickly, while calves and thighs stay warm from muscle work.
A silicone band at the top hem holds them in place, and it sits under the leg of the shorts. The order of dressing is important: the knee warmer goes under the leg hem of the cycling shorts, not over it. That way nothing slips, and no cold gap appears.
Knee warmers fit in any jersey pocket. If you ride in spring or fall, take them along even when it looks warm at the start. On the descent, the math looks different.
