I am probably preaching to the choir here, but just in case I'd like to mention that Relative humidity at room temperature is not
the same as Relative Humidity in your incubator.
Humidity is the effect of the water vapour that exists in the air. The method of expressing this is most commonly Relative Humidity.
What this means is that the number you see as a percentage is the actual water vapour that is present expressed as a percentage
of the total possible water vapour that the air can hold. so if for example the air is 50% full (so to speak) you report it as 50%
RH.
Now the problem is that the hotter the air the more water vapour it can hold so for example, if the air is 50% full at room temperature
it may only be 25% full at incubator temperature because the hotter air in the incubator has the capability of holding more water vapour
than the cooler room temp air.
For this reason even if you have 80% RH in your room at say 72 degrees when it gets sucked into the incubator and heated up
to 100 degrees the RH readout will be much lower. This is why you see that number fall when you close up the incubator
after opening it. The temp of the air is increasing so the RH is decreasing.
The term Absolute Humidity simply refers to the amount of water vapour in the air and does not change with temperature.
sorry if I am boring you guys but I do think many have a misconception that the high RH at room temp is thwarting their incubator
control when really it has less influence than you might think.
i got this image from the wiki page but it kind of shows what i mean.
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Indeed, however, here with the humidity, if the incubator is upstairs, it will spike up to a 20 degree difference on the most humid days. This is why they stay downstairs and use the dry hatch method.