Had a good rain last night. Surrounding stations and a friends manual cup gauge all showed around 1.5". My sky reported .55". Not even close. Install images attached. Suggestions? Raincheck is enabled.
Well having it up on the roof you wont get accurite rainfall anyway, Even if it was a bucket system would be wrong far to high to get good rain measurement for any weather station
How long have you had the unit and is this the first rain event? Raincheck took a few weeks to significantly impact my totals but once it did I’ve had multiple storms move through where it was spot on or within a few hundredths.
Mind if I ask why that would be? The rain doesn’t dissipate between the roof and the ground. And being 6’ above the roof keeps anything from blocking the wind. Seems I would get the best accuracy up there, to me
I’ve Had the unit over a year but haven’t been comparing it. I knew it was off in the beginning. There was a lot of talk about it when they were all new. But WF was saying give it time they will make software adjustments. I was in no hurry
Ah I see. I believe raincheck went live sometime in early June but if you haven’t had much rain in the past few months then it probably hasn’t applied many calibrations. I know when it went live we went through a period of very dry weather for 2-3 weeks at a time with no rain and then we would get a week where it rained off and on several days. During those times of rain the accuracy seemed to improve each time and now it is right on the money for my past several rain events so it seems to have calibrated quite well. Maybe yours just needs a few more rain events so the calibration can start to kick in?
So, Catch 22. To get good wind the Sky must be placed high. To get good rain the Sky must be placed low.
As WFStaff has liked this post I take that as an endorsement. @dsj Please address this.
Since the SKY measures rain with a haptic rain sensor, it is possible that a device more exposed to winds and/or experiences any movement or vibration during a rain event could produce inaccurate readings as some have mentioned. However, it is probably too soon to say if that is an issue for yours or not as it only came back online a few weeks ago and yesterday was the first heavy event in that time. As @vtyler98 mentioned, it can take a few events for your mount-specific calibration to be determined.
Please note that we do have an ongoing program where you can submit reports like this so we can more effectively (1) evaluate performance of your SKY and the RainCheck efficacy at your location, (2) improve the calibration of your SKY and (3) provide feedback to the team at MetStat for potential improvement of the MetStorm Live product (which is a component of RainCheck). You can find more information on that here: Rain Update June 2019
Happy to! Yes, compromises in siting apply to any weather station that combines wind & rain (and other parameters) in one device.
While the average rainfall through a horizontal plane will be the same at all heights, the sampling of that rain with a small diameter sensor is more difficult the further you go up in elevation. That’s because rain gauges (haptic or bucket tippers) are designed to detect the rain falling vertically and, when you have more wind, the rain’s motion has a strong horizontal component to it. The more wind you have, the more uncertain your rain measurement (from any rain gauge). The WMO/CWOP ideal for rain gauge siting is 4 to 6 feet above the ground, at a horizontal distance of “4 times the height of the nearest obstruction.” That’s hard to do in your average backyard, so a good compromise is to get it as far away (horizontally) from obstructions as possible.
The anemometer will measure whatever wind it experiences but wind can be highly variable in a small area, influenced by both the height above ground and the distance downwind of obstructions. The WMO/CWOP ideal for a wind sensor is 10 meters above ground level at a horizontal distance of 10 times the height of the nearest obstruction. That’s really difficult for the average homeowner to achieve.
There’s more discussion about mounting location questions (mostly focused on wind) here: SKY didn't record strong winds
And here’s a statement we wrote a while back in a different thread that applies to this topic as well: