Precipitation Not Accurate


I am running a Rachio 3. The standard options for weather intelligence are in effect (I do NOT have the system tied to one PWS, but to the recommended option of allowing WU to provide the data from a cross section of PWS’).

I have noticed that the precipitation added to my zone soil moisture balance sheet is not always accurate. For example on June 20 the system added 0.12" of precipitation when none had occurred at my home (this is not the first occurrence). I’m still trying to figure out Flex schedules, but the addition of precipitation when none has occurred is throwing things off.

In the past I had a PWS reporting to Weather Underground, but have deleted it a few months ago (I had broken the sensor suite when installing an antenna). So I am relying on your API interface to WU to predict and report rain.


  1. Is there a way for me to manually back out added precipitation from the balance sheet? Is the only way to Fill/Empty (all or nothing)?
  2. Would the addition of an inexpensive rain sensor override the WU provided precipitation? I hate to have to buy another PWS and attach it to WU to improve the precipitation reporting. Looking for an effective but low cost option to better report rain at my location.

Pat Koss


On my gen 2 my PWS is used for the actual rainfall (after the fact). Somehow the gen 2 can forecast, from my PWS, and historical records, the forecasted rainfall going forward, but once a day is over it updates the rainfall with the actual rainfall from my PWS. Having a PWS on my property makes the Rachio system work much better. I have read that the main difference in gen 2 and 3 is that the 3 does weather from many more weather stations, and can average several stations, but nothing beats having the info from a PWS on your property.


Unfortunately not. All or nothing at this time.

No. A rain sensor is a very binary “should we run schedules or not?” tool.

My recommendation is to find a nearby WU PWS. The interpolated data we have (at least for now) just won’t be as accurate as a reliable, close by station. Here are my current thoughts:

Gen 3 does have much better weather intelligence than Gen1/2. We give the user two distinct options now.

Interpolated weather data that you don’t have to worry about stations going down or not reporting precipitation which takes the burden off the homeowner of making sure they have an accurate reporting station. Interpolated data is great but won’t be exactly the measured amount that a PWS would give you near the house.

The ability to choose from over 250,000 PWS stations (Gen 1/2 has about 40,000 PWS stations). I’m also wrapping up a WI plus feature that will self “heal” a chosen station, always making sure you are using one that is online, automatically choosing the next closest station.

I hope this helps. Please let me know if you have any other questions.



Yes it does help. I checked some local (within a mile or so) stations and they had rain. But I know we did not.

I’m going to look into what PWS’s work well with WU these days (i see some of the cheap ones have software problems with WU), but don’t cost a fortune.