Converting Pressure Measurements from Pascals to mb/hPa for PWSWeather and Weather Underground

Hello Weather Watch forum,

I have a question regarding my Sparkfun Arduino and Raspberry Pi-based weather station. My station’s config.txt file measures pressure in metric, but when I upload the data to sites like PWSWeather and Weather Underground, they require the measurements in mb or HPa. Based on your experience, how can I resolve this issue?

Thank you.

I think your starting point needs to be finding out what value your weather station is outputting for pressure. Then you can work out how to convert it appropriately.

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To answer the question in the title, 1 hPa = 100 Pa

Maybe hPa x 10 uncorrected for elevation of 658 m (76.7 hPa)?

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Your pressure in Pa seems correct for your altitude of 660 meters.
It is in-line with other stations in your area.
But you have to device your station value by 10 to get the correct value for uploading in mb.


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I found the line of code to calculate and convert the pressure measurement in my Arduino code. I’ll update the system in the coming days when I go up to the roof. Thank you all for your responses and help. Even if I don’t fix the system, I can understand the pressure value by moving the decimal point two places to the left on the displayed number, but I won’t be lazy and will update the system anyway. :smiley:

By the way my pressure seems correct approximately 933 hPa
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I think you only need to move it one place. You’re displayin 9333hPa when it should be 933hPa.

Yes, but 933 hPa is the actual pressure at your station. To convert to sea level pressure you need to add about 77 hPa.