1. clouds 永远是可数的，至少韦氏词典(merriam webster)是这样说，这是文化/语言差异
2. rain
指雨水天气、雨水时不可数
例: We've had a week of rain. 我们已经有了一星期的
下雨天; I love the sound of rain on the roof. 我喜欢雨水落在屋顶的声音 He was standing outside in the pouring rain. 他站立在外边的滂沱大雨中
指雨量、一场场雨的时候为可数
例:There has been some flooding due to the recent heavy rains. 因最近连场大雨引起了一些泛滥
There are heavy rains in the summer. 夏天的雨量十分多
3. wind
指一阵/道风时可数
例: A light wind. 一阵微风
The storm was accompanied by northerly winds. 风暴伴随著一道道北风
而单指风时不可数
The wind is blowing hard today. 今天的风儿有些喧嚣
4. snow...
其实说到这儿，LZ应该可以找出规律了吧
指天气时不可数 We haven't had much snow this year.
指雪本身或电视雪花不可数 She took a walk in the snow.
要加数量词的可数 A heavy snow was falling. 一场大雪
但指积雪时是例外，可不可数看风格，像Soon the
warm spring sun will melt the winter snows.
和The mountains were blanketed/covered with snow. 只要文法对了，积雪任数没问题
参考及例子来源: Merriam Webster (韦氏词典)