Sciatica occurs when the sciatic nerve which runs from your lower back down to your feet becomes compressed or irritated. While the cold weather doesn't cause  the underlying issue like a slipped disc, it could flare the symptoms for a few reasons. Muscle tightness:  As the temperature drops your muscles contract and tighten. If the muscles in your lower back or glutes like the piriformis seize up, they can put extra pressure on the sciatic nerve. Reduced blood flow:  In the cold, our bodies...