Rain levels not matching local

[dsj]

@GaryFunk

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.

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:

@WFmarketing

Regarding the need to mount your SKY way up on the roof… actually, it is not imperative that users mount their SKY up in some scary or HOA non-compliant location. Sure, if you can access a location free of physical obstructions that impact the wind fetch you will get cleaner wind readings. And yes, there are meteorological standards for professional installation sites for government networks. But, let’s be real here, this is your home, your data, your choice to mount your SKY wherever you feel comfortable.

At WeatherFlow we’ve been measuring wind for over 20 years. (We got so good at it that folks like the US Navy, Dept of Homeland Security, and the America’s Cup hire us as special wind consultants.) To do it correctly is a highly involved process that combines excellent siting (that can take months of scouting locations) in addition to quality equipment. You’ve got the quality equipment, but your siting is limited to your house and yard. Most likely, even if you mounted your SKY exactly 10 meters off the ground (WMO standard for surface winds), your wind speed measurements would still suffer due to your surroundings.

So, our advice is: don’t worry about it too much. Wind is the one parameter that is extremely difficult to normalize from a home installation. You should optimize the siting of your SKY for personal utility rather than to meet difficult government standards.