sun shower       
noun [ C ] uk/ˈsʌn ˌʃaʊ.ər/ us/ˈsʌn ˌʃaʊ.ɚ/
 (一阵)太阳雨
a short period of rain that falls when the sun is shining
  To be out in a sun shower is thought to be good luck. 人们认为外出沐浴在太阳雨中会带来好运。 
 Sun showers are unusual weather occurrences. 太阳阵雨是不寻常的天气现象。 
 - More examples
 - Sun showers tend not to last and are usually light.
 - Some people believe that a sun shower means there will be a real downpour at the same time the following day.
 - Sun shower conditions often lead to the appearance of a rainbow.