Is it more humid before, during, or after a rain/storm?

Question

Please include references if possible.

Answer 1

There was a thunderstorm at the Lambert-St. Louis Int'l airport on Aug 25, 2006. Let's look at the observations before, during, and after the thunderstorm.

This is the raw observation code, and I've edited values out to save space and for the sake of clarity.

Start of thunderstorm & rain...temperature is 26C, dewpoint is 19C--yields an relative humidty of 65%.
SPECI KSTL 251743Z 7SM -TSRA 26/19

Rain is getting ready to stop, it has rained for more than an hour at this point...temperature is 24C, dewpoint is 22C--yields a relative humidity of 89%.
METAR KSTL 251851Z 5SM -RA 24/22

Rain has stopped for 100 minutes or so...temp is 26C, dewpoint 21C--yields a relative humidity of 74%
METAR KSTL 252051Z 9SM 26/21

Now, this was an example during the middle of the day and afternoon. Relative humidity goes through a diurnal cycle and increases at night because the air temperature cools down to near the dew point.

Answer 2

Hmm.. I think it depends on your point of reference. From the ground: Humidity rises as the storm approaches. During the storm/rainfall humidity will be around 100%. After the storm the humidity will still be high, but will wane as the storm moves away or the sun dries it out. From the sky: Humidity in the cloud will rise and reach a critcal mass, then condense into rain. As the cloud drops its rain, the humidity will lessen, until the rain stops. The cloud floats over a body of water, reabsorbing moisture to create the same process.

Answer 3

If you're judging by relative humidity, it would be 100% or close to it as it rains. Typically the humidity is highest DURING rainfall. Other times, say, if there's fog before or after it rains, the humidity may still be near 100%.

As far as FEELING humid, typically before the storm, especially if you're talking about a summer thunderstorm during a hot, humid day. The HEAT INDEX would be the highest beforehand.

Answer 4

because relative humidity cannot go above 100%, it might well be equally humid before, during, and after a storm

it depends on several things including the type and height of clouds

WHILE it is raining, the relative humidity somewhere has to be 100%

water condenses when the relative humidity is 100% so that is the humidity in place where the droplets are formed, but not necessarily at ground level where they are hitting

generally, you can be more confident of a very high humidity when it is raining

before or after, maybe as high, maybe not

Answer 5

Well, before it rains, when the wind is blowing in ahead of it, and the temperature is cooling down, the humidity is fairly low. Then of course while it's raining, I guess you could say the humidity is 100%, but you're generally not out in it so you probably don't work up a sweat. But after it blows through and the sun pops out and things heat up and the rain starts to evaporate, then the humidity really sticks to you.

Answer 6

It can be just as hot during the storm and after it, depending on the temperature of the ground. But the humidity is usually highest after the storm has passed the area, because the sun causes the water to evaporate.

Answer 7

If the rain is caused by warm wet air moving in and riding over the top of cold dry air then it is more humid after.
If the rain is caused by cold dry air moving in under the warm wet air then it is more humid before.

Answer 8

Here in south Florida it always feels miserable after the cool rain has stopped. Then the sun comes out and bakes the rain and it evaporates almost immediately and up it goes again.
ref: my body sez so

Answer 9

Well over here in Southwest Florida, it doesnt matter, its always humid here day, night, when ever.

Answer 10

before