The sky above Zhoushan city in eastern China turned blood-red at night on May 23rd.

This phenomenon sparked discussions among numerous locals, with some expressing astonishment, "Half the sky has turned red, what's going on?" while others speculated, "Is there a ship on fire?"

On May 24th, the local meteorological bureau indicated that upon preliminary investigation, the red sky was not a result of natural causes but rather likely due to the local squid-fishing boats testing their lights. The local town government also confirmed this, stating that indeed, the lights were being used to attract squid.

The Zhoushan Meteorological Bureau explained that May 23rd had foggy weather, with high moisture content in the air and a greater number of liquid droplets, similar to a phenomenon observed in 2022.

They noted that the red lights from the offshore fishing vessels, with their longer wavelengths and stronger penetration, combined with the scattering effect of liquid droplets in the atmosphere, resulted in the unusual red glow across the sky.

The video was provided by local media with permission.

5月23日晚，浙江舟山，定海区的居民突然被眼前的天空给震惊到了。因为在他们面前的天空，不再是之前那样漆黑同时带有几颗零星的星星。而是整片天空都变成了血红色，场面看起来异常的吓人。此现象引发众多市民热议，有市民惊奇地发问，“红了半边天，这是什么情况”。也有市民猜测，“是不是船起火了”。
5月24日，当地气象局也回应了这件事情。对方表示经过初步了解，这次天空变红并非是大自然的原因，应该是当地的钓鱿船在调试灯光所导致的。而当地镇政府也是回应了这件事情，表示确实是钓鱿船在调试灯光，这种灯光是用来吸引那些鱿鱼的。
舟山市气象局解释，23日是有雾的天气，空气中水汽含量比较高，液滴比较多，光的折射就会比较多一点，2022年也有类似现象。因为远洋渔船灯光为红色，红光波长较长、穿透力强，同时在大气中液体微滴的散射作用下，会将红光散射到较远范围，于是呈现出一片天区的异常红光现象。
资料显示，2022年5月7日，舟山市上空也曾出现红色天空。舟山气象部门的工作人员曾表示，天空呈现红色是属于光的折射和散射现象，当天气条件较好时，大气中水分较多形成气溶胶，光源或为港口的船舶灯光。