Why Did My Rachio 3 Water For 4 Hours Before Tropical Storm Beryl?


I’m in Tomball, Texas, and I’m trying to understand how the Rachio 3 weather intelligence works. Despite an imminent tropical storm, my Rachio watered the yard for nearly 4 hours last night. We are expecting significant rainfall due to Tropical Storm Beryl, with forecasts predicting up to 4 inches of rain today and tomorrow. I’ve attached some weather forecasts for context. What’s going on?

According to current forecasts, Tropical Storm Beryl is expected to bring heavy rainfall and potentially flash flooding to our area, with up to 2 inches tonight and an additional 3-4 inches tomorrow oai_citation:1,Tropical Storm Beryl LIVE Tracker, Updates & Forecast | Zoom Earth oai_citation:2,National Weather Service oai_citation:3,Tomball Rainfall Forecast, TX 77375 - WillyWeather.

Please consider adding a screenshot of your soil moisture graph and data for the zone that ran, which can help provide additional insight as to why the zone hit the allowed depletion floor despite the forecast.

Sure thing, I added them to my post. Thank you.

Thanks for adding the graphs! Please also consider adding the data, which can be seen by clicking “More Detail” below the graph. This will help show which graph movements came from irrigation, and which came from rain.

Okay, done. Sorry about that.

No problem! Thanks for the additional detail. I agree, it does look suspicious, and it’s probably worth connecting to an official Rachio support rep or power user. I imagine they will chime in on this thread tomorrow during business hours.

In the meantime, here are a few thoughts from my perspective as a regular user that come to mind as I review your screenshots:

  1. It’s possible that the zone watered because at the moment the zone ran, the forecasted rain was insufficient to overcome the required trigger for the rain skip feature. For example, your screenshot showing the weather precipitation forecast on your phone shows .12 in of rain, and your weather skip setting shows 1/8", which calculates to 0.125 in of rain. Obviously you ended up getting a lot more actual rain, but the system will only respond to what is forecasted at the moment the irrigation starts (or leading up to it). Someone from the official Rachio team can correct me if I’m wrong, but I recall reading somewhere in another post that the actual rainfall for the day doesn’t update until the end of the day. If you want the system to skip for any rain at all, you do have the option to consider lowering the rain skip threshold to 1/16", although I think the default 1/8" is probably reasonable in most cases and is not really the core issue.

  2. It seems to me like the core issue might have been an underestimated rain forecast, which could potentially be an issue with the weather source you’re using to predict rain. Obviously you’ll want to make sure you have the right address and weather source selected. The Rachio team has provided some addtional troubleshooting tips for when the system appears to not properly skip rain in the forecast. You can read more about rain skip, including FAQ and troubleshooting tips here: Weather Skip FAQ

  3. It looks like you’ve adjusted your allowed depletion from the default 50% up to 60%. Just for awareness, this raises the “floor” upon which your watering frequency is calculated, and makes the system more sensitive to needing irrigation sooner. This could potentially impact your system’s perceived need for water sooner than what the rain might provide. In my early days using Rachio, I ran into some similar issues with rain. From what I’ve read in other posts and used in my own system, increasing the Crop Coefficient or using Dynamic Crop Coefficient might be a better approach than raising the allowed depletion to achieve more frequent watering, without the potential impact to depletion sensitivity.

I’ll let the official support team chime in further, just sharing my perspectives as a user. Hope that helps!

Or, the entire process of adjusting watering according to ‘forecast’ rain is highly suspect. There are multiple threads on this forum of folks (like me) complaining of watering being delayed due to forecasting. Where I live, the forecast may say rain, but there’s a high probability it will NOT rain exactly where I am. Not watering (in 100 plus degree heat) will kill or severely damage some plants in just one day. Watering based on actual rainfall is the only way to avoid this. So all of my delays (except freezing) are turned off. I’d rather over-water than the opposite.