"冒着"在这里的意思是"不顾并不好的天气; 不顾那细雨"， (他仍然走在街上………)。 冒着就是不顾恶劣的环境、危险等; 顶着。例: 冒着风雨，冒死，冒着危险。

it means to risk, brave (danger, harsh condition, etc.) 冒险 run the risk 冒雨 brave the rain

For this sentence that means under the rain There is other one 他从水里冒了出来。means he is getting out of water. this word has some meanings in different sentences.

冒着 at the risk of 冒着波浪 ship a sea 冒着暴风雨 to brave storm ; to venture a storm 冒着枪林弹雨 braving the storm of shots and shells; under enemy's heavy fire; under a rain of bullets

i support the answer above, it's 冒雨 的 冒