夏季小知识：为什么湿度大会让我们以为更热？
三伏天是一年中最忧伤的日子，不仅是由于三伏天气温高，还由于三伏天湿度大。氛围中的湿度大为什么会让我们以为更热呢？
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Humidity refers to the amount of water contained in the air. As the air’s temperature changes, so does the amount of water the air can hold.
湿度指的是氛围中所含的水分。随着气温厘革，氛围中的水分含量也会厘革。
One of the ways your body cools itself is by sweating. The sweat then evaporates from your skin, and it carries heat away from the body as it leaves.
肢体自我冷却的办法之一就是出汗。汗水从你的皮肤外表蒸发时，会带走肢体的热量。
However, humidity throws a wrench in that system of evaporative cooling. As relative humidity increases, the evaporation of sweat from your skin slows down. Instead, the sweat just drips, which leaves you with a damp T-shirt and none of the cooling effect. When the humidity spikes, we effectively lose a key tool that would normally cool us down.
但是，湿度却会让蒸发冷却机制失灵。随着氛围中的相对湿度增大，汗水从皮肤外表蒸发的速率则会减慢。停留在皮肤外表的汗水会把你的T恤浸湿，并且一点也不会让你感受凉快。当湿度很高时，我们实践上丢失了一个自我降温的宝贝。
When we think of wind on a hot day, we think of a nice, cooling breeze. That’s the normal state of affairs, but when the weather is really, really hot—think high-90s hot—a dry wind actually heats us up. When it’s that hot out, wind actually draws sweat away from our bodies before it can evaporate to help cool us down. Thanks to this effect, what might have been a cool breeze acts more like a convection oven.
当我们想到热天里的风，我们想到的是清冷怡然的和风。正常情况下是云云的，但是当天气十分十分热的时分（好比高于32摄氏度时），干枯的风但是会让我们更热。在天气很热时，风会在汗水尚未蒸发时就将其吹干，从而让我们无法借助汗水蒸发来降温。也正因云云，大热天里的风不仅不克不及带来凉意，反而更像是烤箱的对流加热。
However, being in the shade can make quite a big difference. Direct sunlight can add up to 15 degrees to the calculated heat index.
不外，在阴凉处则会有很大不同，由于阳光直射会让炎热指数上升15度之多。
英文泉源：Mental Floss
翻译&编纂：丹妮
泉源：中国日报网
