At what temperature should I switch from summer shorts to thermal cycling pants?

Most riders switch to thermal pants when temperatures drop below 10-12°C (50-54°F). If you run warm or ride at high intensity, you may be comfortable in shorts with knee warmers down to 8°C. If you run cold, commute at lower intensities, or ride early mornings, you may want thermal pants at 12-14°C. The key test: if your knees feel cold in the first 10 minutes of riding, you need more coverage. Cold knees are not just uncomfortable—they reduce power and increase injury risk.