What is the difference on these? 多云VS阴天

多云 = many clouds
so you're describing there's lots of clouds and it's cloudy
阴天 = gloomy dim sky
so it's overcast

Both 多云 and 阴天 can be seen clouds in the sky.
1. 多云 more means the weather is a little sunny with some clouds but not to shining brightly, and the color of the sky is a little blue or brightly white.
2. 阴天 means you can not see the sun, there are some clouds in the sky, and the color of sky is dim white or gray, 阴天 is gloomier than 多云, sometimes it is like going to rain.

云量在0%至10%为晴天；
10%至30%为少云；
30%至70%为多云；
大于70%为阴天
说明阴天时,云很多, 太阳光无法穿透云层,就会很暗.
多云,云没有那么多,阳光不太足,但是我们还是能透过云的缝隙看到光

阴天是乌云全覆盖，多云是偶尔有太阳

多云 It's sunny but with clouds in the sky from time to time.
阴天 Clouds cover the whole sky.

都有云，但是阴天光线更暗一些，多云光线更亮一些。

多云未必是阴天，但是阴天也可能根本看不见云朵，是白天的空中是乌乌的。

多云和阴天是差不多的意思，但是多云一般是还有太阳，云很多遮住了太阳。阴天一般指看不到太阳而且有要下雨的迹象。

我不知道😄