Humidity level and climate

Ok so I have a question about humidity levels. I hatch hundreds of eggs a week on a small sort of hobby family hatchery. Im always doing research because we all obviously can learn even after doing something a long time. Humidity is always a big question and something your always tweaking. Over and over again you see comments about it depends on your climate, dryer, wetter ect... This makes zero sense to me. I fail to see how your climate plays into it at all so Im curious and maybe Im just missing an obvious point. I can completely understand how with the change of seasons and humidity you may need to add more water containers or take more out to hold a certain humidity in your incubator. What people make it sound like is that depending on your climate you have a different humidity level INSIDE your incubator. Thats the part that doesnt make sense to me. For example we hatch at 99.5 degrees, its does not matter how hot it is outside or cold or my climate, thats still the hatching temperature. So given that if the prime humidity lets say is 55% for the first 18 days why does it matter what your climate is. Yes you may have to tweek how much water you have in there to keep that 55% based on your climate but you dont change that 55% because your climate is different. Sorry its hard to explain in a story but it just baffles me. Also if people would like to chime in on what humidity levels they are having good success with Im always listening. I run about 50% then 70-80%+ the last 3 days.

I'm still trying to get a handle on this myself, so I'll be interested to see what the more learned folks chime in!

I can say, from what I've read, it's not the climate temperature so much as the climate humidity. Folks in the high desert will have to adjust things different that folks in the deep South.

My meter, sitting in my dining room right now reads 27%. Seems my ambient humidity runs 25-35%. I just ran my first incubation attempt, doing a dry hatch, and my humidity inside read around 10%. Makes me think I need more holes in my incubator, or to have water in there.

Local weather patterns affect how much water you need to add to the incubator.
Climate is the average of a bunch of measurements of weather over a period of time, usually 30 years.
The more humid your climate should indicate the use of less water in the incubator. However, if you experience a period of time below average, you have to add more.
Other than that, I'm not sure what you are asking, though elevation can change what humidity works best for incubation.

OK, let's see if I can explain my understanding in a while that makes sense.

There are a couple of reasons that the humidity of your climate makes a difference on the humidity in your incubator. (For better understanding, remember that humidity is caused by the level of water in the air. This is why humidity drops after a rain storm. The water has been removed from the air in the form of rain drops.)

While incubating, you need to have vents open for air circulation. Humidity, unlike temperature, will get "through" these vents and cause fluctuations in the humidity within the incubator. Also, many incubators being used are made of foam. Foam is a porous material and so humidity can "seep" through it and, again, affect the humidity within the incubator.

So, why is your climate important when adjusting humidity within your incubator? Because if you live in a highly humid environment, you have more humidity "seeping" into your incubator already. If you live in a drier climate, you'll need to add more water to up the humidity.

I completely understand all your explanations but they dont really address the question. I obviously know humidity is differenent all over the place and if its more dry you may have a harder time getting humidity where you want it and visa versa. The question though is many people say the humidity needs to be different based on your climate/humidity which makes no sense to me. Lets say the perfect humidity is 55%, yes it may be drastically different methods to get and hold that depending on your climate but the end game is the same 55%. Not 50% in one climate and 60% in another, does that make sense.

I think they must have been confused or expressed themselves badly as you are correct on that. There is a lot of debate as to the ideal humidity anyway, and then you need to factor inthat all egg shells are porous and lose moistures at different rates anyway (duck eggs particularly so) and you find that the 'ideal' humidity for one egg will not be ideal for another even within the same batch. I wouldnt worry too much as long ax the air cells are the right size and the hatches are working for you. You may find that people run their humidity a little higher in dry arid areas to compensate for when they have to open or the moisture lost from air vents etc