I am simply looking for the humidity accuracy of the Wyze sensor.
I am asking this because 2 sensors I have in close proximity (1 foot) are NOT reading the same humidity. They are 6% apart. Temperature looks fine. Humidity is an issue.
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It’s pretty common to see a 5–10% difference between two sensors (I’m talking about for any brand, not Wyze specifically), even if they are sitting right next to each other.
The main reasons why:
- Manufacturing Tolerance: Most consumer-grade sensors have a rated accuracy of +/- 3%. If one sensor is reading 3% high and the other is 3% low, you get a 6% total gap while both are still technically “within spec.”
- Calibration Drift: Over time, the chemical film inside humidity sensors can “drift” due to dust, off-gassing from plastics, or exposure to extreme humidity. This is why many high-end smart home users (like those on Home Assistant) use “offsets” to calibrate them.
- Microclimates: Humidity isn’t perfectly uniform. Even a one-foot gap can put one sensor closer to a subtle draft, a cold exterior wall, or a heat source (like a power outlet, wires in the wall, or even its own internal batteries), which changes the local relative humidity.
- Response Time: Different brands or models have different “poll rates” And it’s possible that even ones from the same brand, like in this case have their refresh interval alternating at different times. If the humidity in the room is changing, one sensor might be reporting data from X seconds or minutes ago, while the other just updated, leading to a temporary discrepancy.
The test: If you want them to match, I have heard you can perform a “Salt Test” (sealing the sensors in a bag with a damp salt slurry, which creates a fixed 75% humidity environment) to see which one is more accurate. The downside is that as I recall, Wyze doesn’t give us any offset option to calibrate the difference, but at least you’ll know.
One test I would try just swap their position and leave them there for a while and see if they still maintain their difference or not.
I’m guessing the most likely answer is that the truth is an average of both of them… That one is high by 3% and one is low by 3%.