Does ACTUAL rainfall today affect whether to water tomorrow?
I live in central Florida, where the weather is what I'd call hyper-local. Due to the very narrow rain bands, it can be pouring rain in my neighborhood, while five miles away it's dry.
As a result of this pattern, I've opted to use Wunderground with a PWS located <1km away to use with my RainMachine. This is the ONLY weather source I have set (even turned NOAA off).
I have my rain machine set to water every four days, but I'm having trouble figuring out what determines whether it will skip a day or not. Yesterday's forecast was for a tiny amount of rain, at 0.12", but due to some strong rain bands that ended up coming through, we actually received 1.24".
Even though we received this large amount of rain yesterday (and it's reflected by the PWS data accessible through WUnderground), my RainMachine wanted to water the lawn today. I had to manually pause the watering to get it to skip the cycle.
I guess this has me wondering what goes into the decision to water or not? Is ACTUAL rainfall taken into account at all, or is everything just based on forecast amounts?
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How much it wanted to water in percentage ? If the large rain even was "yesterday" it means that the data from WU PWS is already available "today" (this is how WU gives observed data) in which case RainMachine will calculate what we call "Forecast correction" which means it had a QPF (forecast) of 0.12" but actual RAIN (PWS) was 1.24" which gives a 1.12" extra water. If the zone field capacity can soak 1.12" or water this is the water that will be available for the future. If not then this is reduced to zone field capacity + a certain surface accumulation (depending on slope and other parameters).
After this it will look if this extra water is enough for the next 4 days if yes, it won't water, if no but below a beneficial threshold it will postpone to next cycle after 4 days (8th day), if no it will water reduced percentage.
I have a feeling that the WU PWS report was not quite reliable. This seems to happen lately pretty often with WU and it's something we want to address in the next update.
Can you please check the actual data received from WU in Web UI > Settings > Weather > Rain Observed ?
Can you also check the graphs for Available Water on one of the zones that it wanted to water ?
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It wanted to water 103% today. Below is the chart for one of my zones. (In my previous post I reported the forecast incorrectly for yesterday, the 12th. The forecast was actually LOWER, at 0.04", not 0.12"):
Below is the summary for today. Note that it's only reporting 0.35" since last run, even though we had 1.23" just yesterday.
Below is the chart showing how much rain was actually received. I don't understand how it seems to "know" about the 1.23" of actual rain in the chart below, but this isn't reflected in the summary in the chart above, where again, it only thinks there has been 0.35" since last run.
Is there something I'm missing here? Thanks for any help or advice!
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OK, looking at the temperature data reported by the PWS, it looks like recently it's been reporting the high about 10 degrees higher (F) than actual. Could this be throwing things off enough to cause what I'm seeing? I can switch to a different PWS if that will help. It's a bit farther away, but seems to at least give more accurate temp data.
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Yes, that would impact but I think the main problem with your setup is that you have a very small Field Capacity (0.22"). I'm not sure why your zones are set to Sand as this is the lowest field capacity. There is no way such a big rain even will be completely taken into account with such a small Field Capacity because from RainMachine point of view it doesn't have where to be stored. If you wish to keep Sand I would at least increase the field capacity by the +/- signs in Web UI.
I looked at the cached data and indeed all your rain events were correctly taken into account but limited by the Field Capacity.
As for reporting, we only show QPF not RAIN although we should but the current UI is targeted to default setup that doesn't use PWS. It's something that we'll be improving.
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