Why dew point increase after sunset?
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Today (not only today), my termomether in flat shows 31 Celzius and 30% humidity. After sunset, the temperature stay 31 Celzius, but humidity increase on 50%. This mean that dew point increase.
Why this happend? Not only today, all the summer is like this.
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@vujacicm ,its all about outside conditions,cold air is wetter than warm, and seeps in,cause yourse flat aint vacuum proof,therefore undulations in rel hum also inside, maybe your house should be better insulated ,easier to control environment. use a slingpsychrometer to rule out instrumental errors...
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@Ørjan-P-Stien I think is something like this. When outside is 35, in my flat is 30. When outside is 20 in my flat is 25. My walls maybe have 27,5. When outside is more hot then in my flat, dew point in my flat is low. When outside is cold, my flat has high dew point. When sun rises, something take my humidity out. After sunset, humidity is transported in.
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@Ørjan-P-Stien Maybe I found answear.
This is surface dew point
This is 1000mb dew point
During day, humidity goes from surface to 1000mb, after sunset goes from 1000mb to surface. Maybe here is the answear.
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The increase in humidity after sunset, while the temperature remains the same, is due to the cooling of the air, which causes the relative humidity to rise. As the temperature drops slightly or stays constant, the air can hold less moisture, so the relative humidity increases, even if the actual amount of moisture in the air (dew point) doesn't change significantly. This is a common occurrence during summer evenings, especially in warmer climates.
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@Shah-sahb Evaporative cooling means that air drops and relative humidity increase. But here the temperature stay constant, not decrease. But this happens in my flat, not outside. Outside temperature drops, but relative humidity increase. This means that dew point in flat increase, what means that something brings humidity in my flat.
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Increase in humidity inside your flat without a temperature drop indicates that moisture is being introduced from an internal source, such as cooking, showering, or a humidifier. This could be causing the dew point to rise, making the air feel more humid. You might want to check for any activities or appliances that could be adding moisture to the air inside your flat.
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@Shah-sahb This is also, what I have in mind. I need to check one afternoon without all activities, then I will now, if this is the reason. Maybe is really not from outside.
