How close should a PWS be for it to be worth using

The Rachio app tells me there is a Personal Weather Station that is 2.7 miles from my house. Should I use that or not? Is there a rule of thumb for how close a PWS should be for it to improve the accuracy of Iro?

Does the PWS info override the national weather info when the Iro makes a decision, or is it just one factor considered along with several others?

Hi @Ed3120, good morning. Great question!

Personal Weather Stations (PWS) are great if you know they are reporting accurate weather. Since anyone can set one up, we’ve seen the full spectrum in weather reporting. Some stations are very accurate, whereas others not so much. Please keep this in mind as your Iro is only as good as the information fed to it from said stations.

The PWS, if enabled, at this time will only be used for Weather Intelligence/Virtual Rain Sensor readings (for more information, please see: Due to the weather reporting issues mentioned above, we still use National Weather Stations (NWS) for all water budgeting and scheduling creation calculations (for more information, please see:

Hope this helps and you’re enjoying your Iro :blush:

Best, Emil

i live in ga where we have hill billy overload so i have noticed something (just an observation):

im currently analyzing weather data in my area to help me understand the most effective way to schedule the iro (and provide a base line i use to measure efficacy of the iro) and what i have found is that pws(es) that do not report pan evaporation levels seem to be the least accurate/most volatile. i assume because they carry a higher price tag and every yahoo in the state is not throwing these up to report to various weather services.

i have found this site to be useful in validating other pws(es).
my program discards and pws(es) that are more than 1 sigma out of standard deviation (where absent data gets the highest possible values) and the pattern that is beginning to emerge is the absence of pan evap data.

i hope this helps some, at first, the site i provided is un-intuitive but after you go 8 seconds on a link click rodeo, you will find all of the available court certified weather stations and then you can cross reference the pws(es) you desire with these highly maintained/calibrated weather stations.

sorry i cant tell you exactly how to determine the station you should use, but if it was explainable, these guys would have already coded an algorithm for it. hell my method is flawed as well, but i have given myself a false sense of security in my methods/data so i speak it as truth.

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@plainsane @emil @Ed3120 From what I’ve seen of most PWS data, my general rule of thumb is not to use one unless you trust and know the source.