Is PWS used for evapotranspiration?

I’m also curious about using a near by PWS. If a PWS is used, does Rachio use the PWS data to calculate the evapotranspiration? If so, is the actual data used or is it forecasted?

No. We use forecasted data for ET and then use the closest National station.

Here are more details on how the sausage is made and why. :wink:


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My ET in Rachio is always much less than what my PWS says and I trust my PWS more as it is very well sited (I was an atmospheric science major and weather stations are kinda my thing) and the nearest national station (ASOS) does not reflect the conditions at my exact location well due to ocean influences, especially in the Spring.

I am using flex schedules, so what is my best course of action to make sure my lawn/plants are getting enough water? What setting would you suggest I tweak first?


If you want to increase frequency (ET is higher than what we are reporting) than the easiest dial is your crop coefficient (how fast it is burning ET). The closer to 100% the closer to full ET realization. I’d maybe start by increasing it 5%-10% and then looking at your moisture graph to see what the simulator for the next two weeks is showing.


Thanks so much for the info!!

When I reset the defaults to my zones in advanced settings, the crop coefficient for both cool season grass and annuals is the same 80%. Is that correct?

On the page you linked to above, in the example it says the CC for cool season grass is .85, but in the chart immediately below on that same page, it says it is .7 for cool season grass.

I am so confused, can you please clarify what the CC is for cool season grass and annuals?

The article has been updated. Cool season grass is 80% default crop coefficient.


Perfect, thanks again!!