Based on themicap s data, the three rare rainy and snowyweather p rocesses occurred onMarch 5 2005, February 1 2007 and
January 27 2008 in L incang of Yunnan p rovince, were analyzed and compared from the circulation features, characteristics of cold air
and physical quantity fields. Results showed that the three weather p rocesses occurred in favorable weather situations, the strong or
weak cold air and differentwater vapor sources, and different distribution ofwater - vapor flux divergence, vertical velocity and p seudo
- equivalent potential temperature resulted in less ormore p recip itation during the three rainy and snowy weather p rocesses.