Setting up Personal Weather Station to integrate with rachio (gen 2) directly from internet


@MarkSanDiego, I also respectfully disagree. I live in the Charlotte, NC area and my favorite example is a day when I was watching the Panthers game on TV, just 14 miles away from my house. They were getting a deluge of rain so bad that there were waterfalls in the stadium and they had to empty the first row of seats. And I was looking outside seeing sunshine and I never got a drop of rain. And many of us in my town joke that it doesn’t rain in Mint Hill – everything around us will get rain and we miss it!

My closest Commercial weather stations are 10 and 15 miles from my house. The rain they record is almost always very different from what I get. I’ve been toying with setting up my own weather station, but in the meantime I use a PWS 2.5 miles from my house. Not perfection, but from my unscientific monitoring, it seems much closer to my conditions than the commercial weather stations.


There is no question that an onsite weather station will be more accurate than a nearby commercial weather station. The issue is really cost, reliability, and not fooling yourself to think that if you have more accurate weather information the Rachio will do a precise calculation of watering needs and you will not have do anything further.

The formulas used in Rachio are based on estimates of several variables, many of which are not precise. For example, soil type is estimated by the user, not generally analyzed by a lab. Moisture penetration (depth after watering) is not usually sampled by users, and if it is, it is not usually sampled in all areas of irrigation where many variables such as spray spacing, water pressure, pipe-sizing also play a role in how “even” the water is distributed. We have an efficiency coefficient in the Rachio that is an estimate of this water “eveness” of distribution. Drip irrigation systems are not uniform in their distrubition of moisture and are highly dependent on spacing of the drippers to determine an approximately equivalent precipitation rate. The use or non-use of mulch greatly affects the watering needs. The user has to estimate “root depth” of their plants. Each one of these parameters is subject to error in estimating the correct value.

With all of these variables, it is apparent that the Rachio calcualtion is a good first start, but some fine tuning is necessary to ensure you are getting the watering depth and frequency that is best for the plants. When you fine tune the end result, you will be taking into consider not only errors in estimates for soil type, root depth, efficiency coefficient, but also some errors between internet weather report and actual onsite weather.

I guess my point is that the fine tuning is necessary regardless of how good your weather reporting is, and the fine tuning will also compensate for some inaccuracy of the weather report. Given that you should be fine tuning the end irrigation solution, is spending money and time on a onsite weather station going to improve your results enough to be worth the effort?

Weather stations costs money. If you avoid spending money by tapping into your neighbors weather station, you don’t know if it wil be reliable and maintained as a commercial weather station will be and if errors in function will be detected. You will therefore have to monitor this weather station for accuracy, something you will not have to generally do with a commercial weather station.

There seems to be great enthusium for “very accurate weather” input into Rachio. But, you have to weight this against all the other factors that are only “estimates” of watering needs and the need to fine tune the final result regardless of weather accuracy. The fact that your weather from the internet may not be exactly what you are experiencing is probably not a very significant factor relative to all the other “estimate errors” that go into the calculation that Rachio and the user are making in setting up their irrigation system.

Certainly there is a “hobby interest” in setting up a weather station. It is an educational experience that in itself is often worth doing.


They will be shipping the air and hub portion soon, the sky unit was recently modified and hopefully will go into production soon after testing, fingers crossed. But I’ll post as much as I can as soon as I can. I’m being optimistic.


I have a Vantage Vue that works in conjunction with a Raspberry Pi ($35) running Weewx (free) to serve up my weather data to CWOP and Wunderground. You do need the Davis Datalink datalogger in the console but there is no need for their software and no need for the MAC.

WeeWX is a free, open source, software program, written in Python, which interacts with your weather station to produce graphs, reports, and HTML pages. It can optionally publish to weather sites or web servers. It uses modern software concepts, making it simple, robust, and easy to extend. It includes extensive documentation.

So no need to replace you Vantage Vue if it is working.


Your point seems based on the premise that the discrepancy between the nearest commercial weather station vs. what actually fell in the yard is small enough to be “tuned”.

I’m not sure how weather works in San Diego, but here in the Mid-Atlantic, pop-up summer thunderstorms regularly result in some areas getting drenched (1" of rain), whereas areas only a mile away get literally no rain.

That can take a yard from “empty” to “full” without Rachio being aware of it. Or worse-case, having Rachio think that rain filled the yard all the way up to “full” when it’s actually “empty”.

Have that happen to you a few times a month during the hot summer and see if you can fine-tune your way out of it… :slight_smile:


Thank you. Does this work with a Mac? Also, will it work without having my Mac running 24/7 by connecting directly to the internet? Also, is it plug and play? I am not a software developer and, therefore, have no experience messing with code etc. I just want something that ultimately can report to so my Rachio irrigation controller can see the rain information. Thanks very much for your reply.



You can run it on the MAC but you would need to have it running all the time. Much easier to let the Raspberry Pi do all the work since the Raspberry Pi can connect to your network. For administrative stuff on the Pi you can get to the Pi with a simple terminal window or use an old monitor, mouse and keyboard. Once running there is little need to get to the Pi.

It is not totally plug and play but you don’t need to be a programmer to set it up.

This is from the weewx user guide.

In the world of open-source hobbyist software, weeWX is pretty easy to install and configure. There are not many package dependencies, the configuration is simple, and this guide includes extensive instructions. There are thousands of people who have successfully done an install. However, there is no “point-and-click” interface, so you will have to do some manual configuring.

You should have the following skills:

The patience to read and follow this guide;
Willingness and ability to edit a configuration file;
Some familiarity with Linux or other Unix derivatives;
Ability to do simple Unix tasks such as changing file permissions and running commands;
No programming experience is necessary unless you wish to extend weeWX. In this case, you should be comfortable programming in Python.
If you get stuck, there is a very active User’s Group to help, but, please, try to solve the problem yourself before posting.

You will need the Weatherlink USB which rainmanweather sells for about $110.

Let me know if you need any help and we can get you going.


WeeWx is a great solution with the Raspberry pi. What is nice is it can sync with multiple services (Wundergound, any FTP location for your own website, as well as PWS). I’m using the Davis Vantage Pro2. The whole system has been very reliable. The only maintenance is upgrading WeeWx if you want from time to time and cleaning out the rain collector. Some of the stuff that gets into that can be pretty yucky. Here’s what it looks like from my web site:
My Neighbor and I are both linked in to my weather station and the lawns look good and are not overwatered. We’re really happy with the combination of Rachio and the Vantage/WeeWx.

Good Luck,


It really depends upon how much you want to babysit your irrigation system.

Regardless of which weather station used, Rachio will only consider weather that “has already happened”. That is, at some point prior to the start of your irrigation cycle (1 hour or possibly several hours, depending upon the type of irrigation schedule programmed), it will check for rainfall and if sufficient rainfall has occured will then block the irrigation cycle or reduce the irrigation cycle.

What are you likely to do if the weather report is for “heavy rain tonight” but it has not yet occured? If you are inclined to monitor the system closely, you would probably manually intervene and delay irrigation until you know how much rain occured during the night. If so, then you would also probably also intervene if it just started raining cats and dogs and Rachio doesn’t know that because it checked weather 1 hour before your irrigation cycle started.

I recognize that it can rain at your house and not be raining 1-2 miles away where an internet weather station is. However, does that really happen often enough to warrent the extra expense and complexity of a local weather station? It might, but I suspect there are only a small percentage of users that are in this category.

Also, consider the consequences of of a rain discreptancy occurring. If your location gets the rain but the weather station does not, then an unnecessary watering occurs. For most homeowners this is not a big deal if it seldom occurs as daily watering expense is relatively low compared to a commercial farm operation. If the weather station gets rain and you do not, then you will not get the irrigation you need. But, you will also get notices that irrigation has been blocked by rainfal, so you will still be able to take action by triggering a manual cycle the following day.

It really all depends upon how much time and effort you want to put into continuously monitoring your system to get it as close to perfection as possible. I think the majority of Rachio users want to set the system, fine tune it if estimates are not providng desired water, and then forget about the system thereafter. That is the strongest attraction for most users to buy the smart controller in the first place.

My comments are really directed to the majority of Rachio of users, rather than a few in special circumstances or with users that have a strong intersest in monitoring their system closely and optimizing it whenever possible. Most users will not get enough benefit from local weather stations to warrant the cost and time to learn how to correctly implement it compared to using internet weather reports. For those users that decide to tap into a neighbor’s weather station, they will also need to monitor the functioning of that weather station to ensure the weather station continues to function normally and that the neighbor takes corrective action if it fails. Many neighbors install a weather station out of educational interest, but do not necessarily have the interset to maintaining its accurate operation. This additional oversight obligation placed on a Rachio user using a neighbor’s weather station does not generally exist with commercial internet weather stations, which are independently monitored for correct operation and repaired promptly if found to not be reporting accurately.


Thank you Peterh. I have looked around and for this Raspberry pi. It looks like a circuit board with no housing. And, I have looked at the Weewx website. Remember I have an iMac (and not a pc)! And, in any event, I do not want anything that would require my iMac to run 24/7 to share data with services like Wunderground or With all due respect, unless I am not being told 100% of the truth, it was my understanding that I could purchase the Davis WeatherlinkIP for close to $200.00 and, though I would not be able to see the data being produced by my Vantage Vue (except on my console or on through a website that I go to on the internet) on my iMac (which is fine with me as I am not necessarily interested in saving weather data on my iMac for some esoteric functions such as graphing or historical data), with the Weatherlink IP I would ultimately be able to report my data to Wunderground and CWOP. For the purpose of Rachio, once on Wunderground and CWOP, wouldn’t I be able to have the data transferred to so that my Rachio would have access to data produced by my weather station? Is the solution you and our other colleague proposed (using Weewx with Raspberry pi) simply a means to avoid spending $200 (not that I want to waste money) or is it because it works better and/or more efficiently? I am a little reluctant, if unnecessary, to download software to my iMac if I am seeking a solution whereby my weather station can report directly through my router to the internet (i.e., Weather Link) and then to Wunderground and CWOP and hopefully ultimately Am I not understanding something about this set up? Thanks for your reply.



Rachio does look at future weather many days in advance. Not just the past.

There is no effort once a PWS is set up. At least if it’s a good one that’s set up correctly.

The Rachio + PWS will actually reduce the amount you have to babysit your system. That’s why I bought it.

I’ll save roughly $10 every day I don’t water. No doubt in my mind the rachio system and PWS will pay for themselves over time.

No one “has” to use a PWS. But no need to be told they shouldn’t either. It’s a choice they want to make. :smiley:


Mark, you don’t use the Flex Daily functionality, do you?


These days there are many solutions to every technical issue. It looks like their solution may be the easiest to set up for what you want to do.

The Raspberry Pi and WeeWx are fun for geeks, but can be frustrating. Now that it’s running, I can just forget about it mostly. Here’s what my setup looks like.
Enjoy all the technology.


Yes, I’m on Flex Daily for all zones.


It looks a maximum of 48 hours into the future, per their video on smart weather adjustments. But, not sure how a future 50% probability of rain will translate to delaying an irrigation cycle on the possibility that it might rain.


Oops. Deleted comment coz posted on wrong thread!


The flex daily moisture level graph shows expected precipitation and Evapotranspiration for the next 2 weeks, not 2 days. I haven’t seen the video you are referring to. These are based on future weather forecasts. They are adjusted each day, so in effect the future weather just up to to the next scheduled flex watering date is actually used to determine whether to water a zone on the current date. I have a flex schedule which can only run 3 days a week due to local watering restrictions, so the next 3 days of weather forecast is needed to determine whether to water each zone.


At 0.45 minutes: Rainskip only looks forward 48 hours. Others estimate are based only on historical rainfall.


I was curious how you haven’t run into the situation where the amount of moisture in your lawn differs greatly from Rachio’s calculation (due to a PWS reporting rain that never fell in your lawn).

For me, this happens regularly during the summer, and it throws Flex Daily calculations off indefinitely, not just for the “next cycle” that you keep talking about.

Looking at San Diego’s weather, this starts to make sense:
Average Rain:
Jun: 0.08
Jul: 0.04
Aug: 0.04
Sep: 0.16

Where I live in Virginia…
Average Rain:
Jun: 4.25
Jul: 5.16
Aug: 5.15
Sept: 4.76

It seems you live in an area where summer rainfall is literally irrelevant to Rachio’s calculations. On average, its such a low amount that if your lawn were to receive the entire average months worth on a single day, it would likely be less than what the lawn uses up in evapotransporiation for the day…

On the other hand, where many of us live, we can get several inches of rain on one day, and nothing for another week. If Rachio’s Flex Daily calculations get out of whack (due to what a PWS reports being different from what the lawn received), we cannot depend on evapotranspiration fixing the calculations the next day, like how it appears to work in San Diego.


With the amount of rainful you are receiving and the micro-climate nature of your location, I would agree that a PWS makes the most sense. I hadn’t considered how different your weather conditions are from mine!