I have a LaCrosse WS2310 weather station. I have my temp/hum sensor sitting on a side wall of my house at a height of about 3 meters (10 feet). On my website i also use the metar data of a nearby airforce base. What i noted is that my humidity reading is always 6-7% under the airforce base reading. Also, my humidity only gets to 92-93% in thick fog. The airforce base is about 15 kilometers away, so i am curious to know if i can change my humidity reading with a change in offset.
I understand that there is a lot of stuff that influences the values measured. One of these is probably the way my sensor is fixed to the wall, while it should be in open air. Perhaps even the height is wrong.
I don’t really care too much about that, it doesn’t have to be dead on, as long it is fairly accurate and not 6-7% off.
If i were to offset my humidity value in WD by say 6%, woudl that be ok overall? Or would that be a stupid thing to do?
[quote author=henk99 link=topic=6274.msg41405#msg41405 date=1100689383]
Hi all,
I have a LaCrosse WS2310 weather station. I have my temp/hum sensor sitting on a side wall of my house at a height of about 3 meters (10 feet). On my website i also use the metar data of a nearby airforce base. What i noted is that my humidity reading is always 6-7% under the airforce base reading. Also, my humidity only gets to 92-93% in thick fog. The airforce base is about 15 kilometers away, so i am curious to know if i can change my humidity reading with a change in offset.
I understand that there is a lot of stuff that influences the values measured. One of these is probably the way my sensor is fixed to the wall, while it should be in open air. Perhaps even the height is wrong.
I don’t really care too much about that, it doesn’t have to be dead on, as long it is fairly accurate and not 6-7% off.
If i were to offset my humidity value in WD by say 6%, woudl that be ok overall?
Your problem sounds just like mine. Every weather station, airport, Air Force Base, everybody was reporting 100% humidity, except me. My weather station never went above 93 or 94%. It was so humid at my place that my deck looked like it had rained
I use the Davis WMII and it has a cal factor for the humidity. It was set at 0000% as shipped from Davis. I ended up adjusting it to 0010% giving me 99% on the console. But, WD was not picking up the new value for whatever reason. Most likely it’s a problem with the console and how it reports the data to WD.
So, I went into WD under Setup – Control Panel – Barometer offset and at the top of that screen is a humidty offset. I set that to match the console cal factor of 10%. Now both WD and my WMII console agree on the humidity.
BTW, I did not tick either “Set xx% as 100%” and I left the slope factor at the default of 5. I also did not tick the box for “Use prop. offset in inc. the value more when lower humidity” as I have no idea what that is for…
My personal feelings are that if all stations near you are reporting 100% humidity, and everything at your house is covered with condensastion making it look like it just rained, then chances are pretty good that the humidity is at or close to 100%.
I think my station is closer to the actual humidity reading than it was before I made the adjustment.
my WMR928N humidity readings always hit the sensor’s max of 98% when I had the temp/hum sensor out in the open under a makeshift solar radiation shield. Since I put the sensor in a proper Stevenson screen (to make the temp reading more accurate) the reading has never gone above 91% yet - I could set an offset to read higher but that would make all readings too high, so I guess I have to put up with it.
I think in my case the humidity is correct on dry days as it is always close to readings from a local airport - but when it rains or is misty it levels out at 90% or so and does not go higher even when other local readings do. Must be the Stevenson screen not letting moist air circulate effectively.
