Handling Afternoon chance of rain

In my area, during the summer, we pretty much have a 10-20% chance of thunderstorms. They are almost always scattered. (For example, I went to dinner last night two miles from my house. Left in pouring rain. Drove home and I never got even one drop.)

Luckily either one of the storms eventually pans out or it finally gets forecast for so little that the system will water, but there have been times where I’ve had to manually water my drip systems because the plants are wilting. I’ve been wondering if the forecast chance of rain is 20% or lower and it’s for those possible afternoon thunderstorms if it would be better if Rachio would just ignore it and think it’s going to be zero precip. It would be a nice addition if it were an option for the user to choose to ignore the forecast under those conditions by zone…

I’d like the option by zone as my lawn seems to be able to go under my MAD for a day or two without really hurting it, but my drip zones seriously suffer (I see plants start wilting) when they don’t get the needed water.

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Or have the Rachio run 80% of the time that there is a 20% chance of rain?


It would be nice to program rain skips based on % chance of rain reported from weather stations. I live in Florida and scattered thunderstorms is the norm during the summer. I’ve actually experienced rain across the street and not a drop on my side of the street.


Hopefully these pics will show why this is so critical. We’ve had a 20-30% chance of rain EVERY afternoon for the last week, and here is my moisture graph:

The zone didn’t water yesterday, went drier than the MAD, and then based on the forecast, decided not to water again today – it’s now 7pm, and the rain appears to be missing me yet again.

Here’s how my hydrangeas looked this morning. From what I’ve been able to research, it’s not bad if it wilts a bit during the day but recovers by the morning. This one (along with all my other hydrangeas) did not recover overnight. Luckily I was home to observe this, and I was able to run the zones manually. But I’m soon going to be out of the country, 5 time zones away, with spotty internet service. I am just hoping that everything will survive.

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Can you ping me when this happens again (before the next day)? I want to review the POP (percent of probability).


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@franz, as my luck would have it, last night my weather station (2.5 miles from my house) got .19 inches of rain and I got nothing at my house!!!

I’m traveling right now so will try and monitor as I can. Good news is that my rain sensor activated so I finally got rain at my house.

I have wondered about rain skip as well. I had a situation where i got a skip due to a good chance of rain that day, and it did not rain (either at home or my weather station). Instead of then watering the next day, it waited until the next scheduled watering. I theorized that with the current logic one could get several rain skips, no participation, and you could unduly stress your turf.

It seems it would be an easy programing change to adjust the schedule in such an event: Skip due to chance of participation. Did it rain? YES: then wait till next scheduled. NO: adjust schedule to water the next day.


Flexible daily schedules do work this way, they adjust one day out. Fixed or flexible monthly schedules do not self correct. I’d like to add this feature but it becomes quite complex with restrictions, etc.

Forecasting is hard :wink: in general, but I fully understand the issue.

Thoughts on weighting forecasting less? It currently works in that if POP (probability of precipitation ) is > 50% we take the full forecasted value, and if the POP is < 50% we talk half the forecasted value.

POP is difficult because it consists of multiple variables that are not exposed.


Would be great to have some weather experts chime in.


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OK, changed to flex daily from fle monthly. Next question…

I made 3 schedules. A single zone that has mister heads (separated it so the smart cycle will work for all other zones), the rest of the front yard, and the back yard. the back gets more sun than the front.

How do I best stagger start times? Do I have to? If I schedule them to start at the same time how will the controller react?

Ok great, do note that you might have to make some adjustments if it isn’t working as you expect, it’s a highly sophisticated watering algorithm that only works as well as the data it has at hand :wink:

Here is a concise overview of the documentation. We also have some great community members that can help out a lot with initial settings.

If you have created different flex daily schedules (in order to get cycle soak for non-mister zones) you don’t need to worry about staggering times, etc. The controller will just queue everything up :wink:


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