Bethesda didn't spend much time on the weather that blankets the wasteland.  It's pretty basic and bland at a stock level.  But, the community has seen fit to correct that lack of attention.  Enter Nevada Skies, a complete weather overhaul for New Vegas.  This mod features over 320 weather variants, special weathers like toxic storms, tieing into the games rads and sneaking systems, and much more.
Credits: Yossarian