About

What the equipment is, how the data gets here, and what the numbers do and don't mean.

Equipment

A Davis Vantage Pro2 integrated sensor suite — anemometer, tipping-bucket rain gauge, and a radiation-shielded temperature and humidity sensor — transmits on 902–928 MHz to a Davis Weather Envoy indoors. A WeatherLink USB logger passes records to a Linux server on the local network.

Software

WeeWX polls the logger, stores every archive record in a local SQLite database, and generates these pages. The station pages use the Belchertown skin. Nothing is uploaded to a commercial weather network, and the server accepts no connections from the internet — it pushes finished pages outward instead.

Reading the numbers

Pressure is corrected to sea level, so it can be compared against regional forecasts. The raw station pressure at this elevation runs about one inch of mercury lower.

Rainfall comes from a tipping bucket, which systematically under-catches in strong wind — by a few percent in light breezes and considerably more in a gale. Storm totals are a lower bound.

Wind direction is corrected for magnetic declination and reported relative to true north.