too many words by laura lemay

weather geekery

Becoming deeply interested in gardening means also becoming deeply interested in the weather. Perhaps not so much as in if its going to be sunny or rainy on any particular day, but more the cycles of temperature and sunlight over the course of the year.

I have a fairly large vegetable garden, and I need to know a bunch of weather facts. I need to know exactly when the last frost is going to happen so that I can get the tomatoes in at the right time. When I lived in the suburbs I could just read the newspaper and the gardening section would say “Plant your tomatoes now!” but up here in the mountains the weather is different; it snows, it gets colder and stays colder and we get more rain. I have to pay closer attention to what actually happens. I also need to know how many hours of sunlight there are going to be every day, which is important for growing onions. I have an Old Farmer’s Almanac that will tell me that. And one other thing I need to know is the number of chill hours we get — chill hours are the total number of hours in the winter below 45 degrees. Lots of fruit like apples is dependent on chill hours and you can’t grow some varieties if you don’t get enough chill.

For a while I had a $10 Target thermometer which measured maximum and minimum temperatures, and for an entire year I would get up in the morning and write down the max and min on a post-it. Every month or so I would enter those values into a spreadsheet and plot elaborate graphs. Sometimes I would forget to write down the numbers and sometimes I would lose a post-it so there would be big gaps in the data but mostly it was OK.

Now you would think that a gadget geek as big as I am would have found a more efficient solution than writing down numbers on a post-it every day. You would think that I would be all over computerized weather stations. You would think. And I have no real excuse for that, other than that I did the research and I couldn’t find a weather station that knowledgable people didn’t dismiss as totally sucky or that wasn’t completely insanely expensive. Also: in the realm of geekery weather geeks seem to be way over the line geeky. scifi geeks…computer geeks…train geeks….weather geeks. Way over the line. I had some kind of weird mental block going over the whole thing. And so I continued to scribble temperatures on post-its.

And then Eric got me a weather station this last Christmas. Its an Oregon Scientific, which knowledgeable people dismiss as entirely sucky. It seems to work entirely fine. It has a bunch of wireless sensors we put up in the yard outside, which send data to the box indoors. It measures indoor and outdoor temperature, barometric pressure, indoor and outdoor humidity, wind speed and direction, rain rate and total rainfall.

Holy freaking shit this is so darn cool.

It comes with a little box that lets you press buttons on a touch screen and see all this data, or you can connect it to a PC with a serial cable and it’ll spit out the data for processing there. Unsurprisingly, there is a lot of open source software to read the data and generate complicated graphs. Eric set it up on our main linux box so that we can obsessively look up complicated graphs on our internal web server that tell us its sunny outside. Eventually I’ll get around to setting up a cron job to upload the graphs to And, of course, with all the weather data busily being stored and graphed soon I will have enough data to be able to write some scripts to generate the chill hours and other data I need for my gardening. In this household there’s no such thing as a hobby that doesn’t require programming.

We also send the data regularly to Weather Underground, one of about 40,000 online weather sites but probably one of the geekiest. Its not a pretty site and its not an ultra-serious weather science site, but for weather geekery its right up there. We are the Above Lexington Reservoir weather station on the wunder site; you can go there and see our data graphed BY THE MINUTE. Look! The barometric pressure is falling as we speak!