Topic: Humidity values

[NHSA]

Hi,

As far as I know when it is raining the humidity is 100% ¿ or ?

If yes, why does my station not report 100% when it is raining ?

Thanks Rainer

[Jim_S]

As far as I know when it is raining the humidity is 100% ¿ or ?

If yes, why does my station not report 100% when it is raining ?

Your basic assumption, that the humidity is always 100% (at your station at ground level) when it's raining, isn't true. If you google the question you'll find lots of info on why this is the case.

However, most of the time clouds and saturated air lie above drier air at the ground (where we live). Measurements of relative humidity that you hear reflect the actual moisture content of the air at ground level — in drier air that is simply being invaded by rain from above.


Very nice telescopes in your avatar. I used to do some astronomy but haven't been very active in a long time.

[NHSA]

As far as I know when it is raining the humidity is 100% ¿ or ?

If yes, why does my station not report 100% when it is raining ?

Your basic assumption, that the humidity is always 100% (at your station at ground level) when it's raining, isn't true. If you google the question you'll find lots of info on why this is the case.

However, most of the time clouds and saturated air lie above drier air at the ground (where we live). Measurements of relative humidity that you hear reflect the actual moisture content of the air at ground level — in drier air that is simply being invaded by rain from above.


Very nice telescopes in your avatar. I used to do some astronomy but haven't been very active in a long time.

Hi Jim,

Thanks a lot. Will do a search.

regards Rainer

[mikemaps]

I don’t know the scientific answer, but I’ve always noticed with the Atlas & Davis stations I’ve had before, the humidity is almost always highest near sunrise & during rain storms will always be less than 100 percent, may be quite a bit less. Dew point tells you more than humidity, you should become familiar with dew point temps.

[NHSA]

I don’t know the scientific answer, but I’ve always noticed with the Atlas & Davis stations I’ve had before, the humidity is almost always highest near sunrise & during rain storms will always be less than 100 percent, may be quite a bit less. Dew point tells you more than humidity, you should become familiar with dew point temps.

Hi Mike,

Yes that is correct that the humidity is highest just before Sunrise. Check the ambient temperature and you will see that the time you mention will be the nearly the coldest of the last 24 hours.

That is also the reason why I set my garden sprinkler system to water the garden as the evaporation losses are the lowest.

Rainer

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