Home Weather Stations and Software

Our new house came with small 64 tree avocado orchard. I spent several days trying to answer what I thought was a very simple question. How much should I water the trees? I discovered that to correctly answer that question you need to know the current Evapotranspiration (ETo) for your area to plug into the CIMIS Water Requirements Calculator. The ETo for most areas within California can be found at the California Department of Water Resources CIMIS Data Page. A description of what ETo is and where it comes from can be found in the UC Cooperative Extension June 1999 newsletter. This seemed like a lot of manual work each week just to know how long to program a timer. This lead me down the path of looking into home weather stations. Any home weather station would need to be computer accessable and would preferably have a web interface. My search of the web did not reveal any single place that had links to most of the competitive products. I therefore decided to make up my own and post it for others.

Software

People much wiser than I have said to find a software solution for your problem, then buy whatever hardware it takes to run it. I have found this to be all too true. I therefore list the software first and indicate which hardware it supports.

All the software listed performed basic logging of weather data and provided some way to generate web pages. Most provided the ability to generate web pages and automatically upload them to your web site. Several of the commercial packages included the ability to download METAR data for your area to supplement the data gathered by your station. Other features included the ability to page/email you when parameters exceeded thresholds. This is potentially useful for warning you if your greenhouse is about to freeze.

SB Weather is windows based, supports the radio shack WX-200 weather station, is 20 dollar shareware and I did not look much further.
Virtual Weather Station is windows based, works with most common weather stations, costs 40 dollars and seems to have all the features of packages costing hundreds more. Upgrades are free.
Weather View 32 is windows based, works with most common weather stations, costs between 150 and 500 dollars based on options and will upload web pages to your web server. Upgrades are half the cost of the original package.
WX200D is the only Linux weather logger I have found. It only supports the Radio Shack WX200 weather station. It is available in full source and is under GPL (i.e. is free). Related scripts are used to generate and upload web pages.

Hardware

The following vendors appear to manufacturer standalone weather stations that offer computer interfaces

Colombia Weather Systems make a range of weather stations ranging fro ??? to 2250 dollars depending on features and options. Computer interface appears built in.
Davis Instruments make a range of weather stations ranging from about 200 to about 2000 dollars depending on options. They seem the most common station referenced by internet weather stations. Their prices are competitive and their accuracy seems better than most. Computer interface is a 150 dollar option.
Maximum Wind and Weather Instruments make a basic weather station for about 550 dollars. Computer interface seems built in.
Oregon Scientific made by Huger and sold by Radio shack offer a basic station for about 400 dollars (200 mail order?).
Peet Bros. Company makes a range of weather stations ranging from about 200 to about 600 dollars depending on features and options. There is some indication that they are popular with the amateur radio community. Computer interface seems built in.
RainWise makes a weather station for about 1000. Computer interface is a 300 dollar option.
Texas Weather Instruments make a range of weather stations ranging from about 1000 to about 2000 dollars.

I found a useful comparison of some of the weather stations at Virtual Weather Stations Stations Specification and Prices.

Conclusion

My interest is in a weather system to help program a sprinkler system. It would appear that the weather system component of this system is obtainable for between 500 and 1000 dollars. The sprinkler component is not such an obvious choice. I will update this page when I learn more about home weather systems.