I always take rain pants, and they are the last line of defense. If it gets too cold even with them, time to crawl into the sleeping bag! There is really little difference in weight or bulk between wind pants (which aren't waterproof) and lightweight rain pants (which are).

Of course I live in an area where even during the dry season, there is waist-high dew-saturated brush to contend with.
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May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey