Infinite Design and Development, Hagerstown, Maryland
This page shows live weather from a personal weather station in Hagerstown, Maryland. The readings are measured on site, saved every minute, and published here as they come in. Records go back to January 2017.
The station
- Weather instruments: a Peet Bros Ultimeter 2000, wired to the computer for near-instant readings (temperature, humidity, pressure, wind and rain). Temperature and humidity sit in a naturally ventilated radiation shield, and rain is measured by a drip-counting gauge.
- More sensors: two extra outdoor sensors, one in the Orchard and one at the Observatory. Each one measures temperature, humidity and lightning strikes. Their temperature and humidity are shown at the top of the readings tile, and their strike counts feed the lightning tile.
- Lightning: two AcuRite lightning detectors count strikes within about 25 miles. Electrical noise (from power lines, appliances or radio interference) can look like a strike, so the two detectors check each other. The first detector to report a strike leads, and the other confirms it: a strike is counted when both report it within a couple of minutes. A detector that is picking up too much interference sits out the lead and only confirms. When one detector is offline, the other counts on its own. A strike that the other detector does not confirm waits for a repeat before it is counted, a lone unconfirmed strike is thrown away, and a very close first strike after a quiet spell without confirmation is treated as noise. The count can therefore lag behind a storm or miss a distant strike.
- Software: WeeWX 5.5.2 with the Belchertown skin 3.0.0
- Computer: a Raspberry Pi 3, shared with the second station. Its own health (CPU temperature, load, memory, power) is shown on the Solar page.
- Power: the equipment runs on solar power. Four 100-watt solar panels (400 watts in all) charge a 300 amp-hour, 12-volt battery bank, made of two 100 amp-hour lithium iron phosphate (LiFePO4) batteries and a 100 amp-hour AGM deep-cycle battery, through a 40-amp MPPT charge controller. The same solar system is shared with amateur radio equipment, phone and battery chargers and other equipment, and it is also a backup power source during power outages. The weather equipment (computer, radio receiver and sensors) draws minimal power around the clock, so the battery carries the night.
- Solar monitor: a small, custom-programmed ESP32 microcontroller reads the charge controller over an RS485 serial link and reports the solar, battery and load voltage, current and power to the weather computer every minute. These are the readings in the solar and battery tiles on the home page, and they are saved with the weather records.
- Sun and moon: the Sky Almanac on the home page is calculated for this location.
- Updates: the main readings refresh about every 10 seconds. Rain, wind, freeze, record and storm events are also published as an RSS feed.
A second station
A second station, run by amateur radio station KB3ISG (a National Weather Service storm spotter, call sign WAC046), has its own page. The two kinds of station run side by side on purpose, because each has strengths the other lacks:
- Wired and wireless: the wired Ultimeter reports almost instantly, which suits fast-changing wind. The AcuRite sends its readings by radio, so its sensors can sit much farther from the computer than a cable would allow.
- Two ways to shield the thermometer: the AcuRite temperature and humidity sensor sits in a solar-powered, fan-aspirated shield, which keeps air moving over it, and the Ultimeter's sits in a naturally ventilated radiation shield. In still, sunny air the two can disagree, which shows how much the shield matters.
- Two ways to measure rain: the Ultimeter counts drips from its collector, and the AcuRite uses a tipping bucket, so each rain total can be checked against the other.
Both stations share the computer and the Orchard and Observatory sensors shown on both pages. Comparing them with each other, and with the nearby airport, is how the history was checked. See the AcuRite station.
Data notes
- Charts and records on this site come from this station's own database, so they will not match other stations exactly.
- In October 2026 the history since January 2017 was reviewed. Gaps were filled and obvious glitches (single bad readings and stuck values) were corrected, using the nearby second station and the Hagerstown Regional Airport (KHGR) observations as a check.
- The Observatory sensor does not have a radiation shield yet. In direct sun its temperature reads warm and its humidity reads low until one is fitted.
Uptime: this computer has been running for 2 days, 6 hours, 22 minutes, and the weather software for 1 day, 15 hours, 35 minutes.