Weather Station Comparison
RainWise MkIII vs Davis Vantage Pro 2
As time permits, and wet fall weather sets in, I will include on this page photographs and comparisons of two popular weather stations - the RainWise MkIII and the Davis Vantage Pro 2. In the meantime, here are charts (updated every four hours) that compare the measurements reported from these two stations.
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Overnight temperatures typically match exactly between the RainWise and Davis. During the day, when the stations are heated by the sun, the RainWise tends to exaggerate temperatures by 4 to 6 degrees. The Davis uses a (solar powered) fan to move air across the temperature and humidity sensors, which minimizes the impact of solar heating. Note the characteristic "bump" in dew point reported by the RainWise as morning temperatures first exceed the dew point. |
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The RainWise barometer is mounted on the outdoor unit, and is subject to ambient temperature variation. When temperatures rise, the RainWise barometer drops; when temperatures fall, it rises. I've adjusted the RainWise reading so that at about 50 degrees, the two barometers match. For each 10 degrees F above (or below) 50F, the RainWise barometer will read about 0.03 inHg below (or above) the Davis. The RainWise barometer is problematic, and offers poor agreement with the MADIS quality control checks. The Davis barometer is typically spot on the MADIS QC checks. |
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The RainWise uses a propeller to measure wind; the Davis uses wind cups. While peak readings typically agree closely between the two, the RainWise appears to be more sensitive at measuring light breezes at less than 5MPH. |
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Both stations uses .01" tipping cups to measure rain. Neither have been changed from their factory adjustment. The Davis typically reads about 5% higher than the RainWise. |