Today’s newsletter podcast is a special treat for readers and listeners of the Beyond the Garden Basics newsletter/podcast who might also be weather nerds…and what gardener isn’t? It’s an interview with climate scientist Daniel Swain, who, besides being a University of California Ag and Natural Resources employee at the California Institute for Water Resources, is well known on social media. Swain runs the Weather West website as well as his frequent presentations talking about extreme weather conditions in California and the west on YouTube, Bluesky, and other social media outlets. The interview focuses on how gardeners can measure weather conditions more accurately in their own yards. We discuss the limits of simple thermometers and the value of weather stations that measure temperature, humidity, wind, rainfall, soil temperature, and other variables, emphasizing that equipment placement is important for getting readings that reflect actual garden conditions. Swain explains that temperature measurements depend heavily on location. A thermometer in direct sun, near asphalt, dirt, or a house wall can read much hotter or colder than the standard shade temperature used by weather services. He says the official comparison temperature is usually taken about two meters (78 inches) above the ground, in shade, and that exposed thermometers can produce misleading highs and lows. The conversation then turns to frost protection in gardens and orchards. Swain says the relevant temperature depends on the plant and its height, because vertical microclimates can differ significantly within a few feet. He explains that cold air can settle near the ground, while higher air may be warmer, and that this matters for citrus, vineyards, tomatoes, and fruit trees. He also notes that irrigation and soil moisture can change daytime and nighttime temperatures. Discussing wind measurement, Swain says rooftop-mounted wind sensors often do not measure ambient wind well because the house creates turbulence and eddies. He explains that spinning-cup anemometers are vulnerable to dirt, rust, and wear, while sonic anemometers have fewer moving parts and can be more reliable. For wind, he recommends placing sensors away from tall obstacles and in open areas. Among the main points in the podcast: * Don’t rely on a thermometer mounted outside your kitchen window; it won’t reflect real conditions in your garden or orchard, which can differ by 6–8°F or more. * Test any temperature sensor in several yard locations before committing to a permanent spot; look for where it runs coldest and where it gets the most sun. * Keep thermometers out of direct sunlight and off dark, heat-absorbing surfaces (asphalt, concrete, bare dirt). These cause false highs by day and false lows at night. * For frost/freeze protection on citrus, hang the sensor at the height you’re actually trying to protect (e.g., ~2 feet, in the canopy shade), not high on a wall or pole. * Remember that a few feet of vertical height can matter more than many feet of horizontal distance, since cold air pools near the ground at night (temperature inversion). * If protecting a ground crop vs. a citrus tree, measure separately near the canopy top and under the canopy. Conditions differ significantly. * Use inexpensive multi-sensor stations (one indoor display, several remote probes) to monitor several yard zones at once rather than a single point. * Consider planting on gentle slopes or hillsides when possible. Cold air drains downhill, giving lower spots more frost risk and slopes a degree or two of protection. * Irrigated soil and plant tissue hold heat longer than dry soil, so damp areas will show a different (often milder) temperature swing than dry ones. Factor this into sensor placement and expectations. * Don’t mount wind gauges (anemometers) on the roofline. House edges create turbulent eddies that produce inaccurate, artificially chaotic wind readings. * For accurate wind data, mount the anemometer on a freestanding pole away from buildings, trees, and other obstacles, as high as practical. * If your station combines wind and temperature sensors in one unit, know that the ideal siting for each conflicts. Consider separating sensors and placing them independently. * Favor sonic anemometers over spinning-cup types if buying new. No moving parts means less error from dust, spiderwebs, or rust, and prices have dropped into the hundreds of dollars. * Clean and periodically recalibrate wind and temperature sensors. Even good instruments degrade and drift with age and grime. * Before designing a garden layout, spend a year observing your yard’s actual sun, shade, drainage, and temperature patterns month to month rather than guessing. Paid subscribers get extra editions of Beyond the Garden Basics, as well as access to over 300 previous editions of this podcast and newsletter. Home Weather Stations Podcast Transcript (originally aired on the Garden Basics with Farmer Fred podcast in May 2025) Farmer Fred: [0:00] If you’re a longtime gardener, well, you just might be a weather nerd. You may want to know what’s happening, especially around your garden area and greenhouse, about many things, such as what’s the high temperature, what’s the low temperature, what about humidity, wind, soil temperature, rainfall, evapotranspiration rate, chill hours, growing degree days, heat index, UV radiation, and a lot more that can be affecting you and your plants. And your meteorological equipment right now may be as simple as a thermometer hanging outside your kitchen window, which may not be the best idea. We’ll have more about that in a minute. Or it could be as complex as a really nifty weather station that set you back $1,000 or $2,000 that sends a myriad of data to your computer or phone or your in-house monitor. So if you’re considering upgrading your backyard weather equipment, you also need to consider the placement of those various devices in your yard to get more accurate readings about what is really happening in your garden area, especially near your food crops. Today, we’re going to get some answers to those questions from Daniel Swain. If that name sounds familiar, you may know him as the man behind weatherwest.com. He’s a climate scientist focused on the dynamics and impacts of extreme events, including droughts, floods, storms, and wildfires. Daniel holds joint appointments as a climate scientist within the California Institute for Water Resources, within the University of California Ag and Natural Resources, the Institute of the Environment and Sustainability at UCLA. And he’s a research fellow at the NSF National Center for Atmospheric Research. He’s an alumnus of Davis and Stanford, and he completed postdoctoral work at UCLA. And again, his Weather West blog is excellent reading wherever you might be on social media, especially Twitter, Blue Sky, and YouTube, where he does presentations all the time about upcoming weather events. I’ve been a fan of his for years. Daniel, I’m finally glad to be able to talk to you in person. Welcome to the Garden Basics podcast. Daniel Swain: [2:15] Yeah, so thanks for the invitation to be here today. It’s great to be on the show. Farmer Fred: [2:19] All right, let’s talk about, I’d be curious about your own home weather setup. What’s that like? Daniel Swain: [2:26] Yes. Well, you know, today where I live, I actually am based physically in Boulder, Colorado these days because of that NCAR appointment, despite the primary one with the University of California. So we don’t own a home here. So I’m somewhat limited when I can personally install on this side of the Rocky Mountains. But back in California, I actually, back when I was in high school, believe it or not, installed a weather station on my parents’ home in the North Bay. And that is something that I have maintained over the years on their roof. It’s still there. It still gets maintained. And I’m still trying to use, to the best extent possible, best practices for meteorological station siting on that one. Farmer Fred: [3:08] I understand completely. I think when I bought my first large parcel of land, I got myself a Davis Instruments weather station, which was at the time one of the best you could buy. And that let me know a lot of things like wind direction, the high temperature, the low temperature, rainfall amounts, things like that. But it has gotten so much better over the last 20 or 30 years. And the data is much easier to comprehend as well because of either in-house monitors or the data is shot straight to your phone or your computer. It makes it a lot easier. As they say in the computer world, garbage in, garbage out. So where you put that home station, no matter where, what kind it is, where you put it in your yard is very important, isn’t it? Daniel Swain: [3:55] Oh, it’s incredibly important. And this is actually something that I think is not always as obvious for a lot of folks as it might be to some meteorologists, although perhaps not even to all the meteorologists in the world who haven’t worked a lot with, actual physical instrumentation. And I think this is because, you know, as you say, exactly where you put these devices and where they are relative to other things that might be, in the immediate vicinity can make a huge difference into the numbers of the data you’re actually seeing in front of you. And, you know, as you mentioned, there’s any number of different ways. Companies that manufacture weather instrumentation or packages of weather stations. For my part, just as was the case with you, the one I installed was indeed, I think it was one of the Davis Vantage Pro stations, sort of the best consumer grade ones that they offered for many years. And it’s still there. It’s still chugging along. It’s been recalibrated a couple of times over 20 years at the factory. But it is still the same origi
