How Weather Station Sensors Work: Temp, Wind, Rain & More

A modern weather station like the Davis Vantage Pro2 or Vantage Vue is really a collection of independent sensors packed into one unit. Each sensor measures a different aspect of the weather, and together they build the complete picture you see on your console or website.

This guide explains how each of the main sensors works in plain language — and what affects the accuracy of the numbers they produce.

How does a weather station measure temperature?

A weather station measures temperature with a small electronic sensor: either a thermistor, whose electrical resistance changes with heat, or a digital silicon sensor that outputs a reading directly. The sensor sits inside a white, louvered radiation shield that blocks direct sunlight — an unshielded sensor measures sun-heated plastic, not air.

Current Davis stations use the digital type, and the published accuracy is good: ±0.3 °C (±0.5 °F) on the Vantage Pro2. The radiation shield around it is passive — stacked plates that let air flow through while blocking the sun — so it depends on a little wind for ventilation. On calm, sunny days even a well-designed shield reads slightly warm, which is why Davis also sells a fan-aspirated version that pulls air across the sensor continuously.

No sensor survives bad placement, though. A shield mounted over asphalt, against a sunlit wall, or above a heat-venting roof will read high no matter what is inside it. Our weather station siting guide covers where to mount the shield so the numbers reflect the actual air.

How does a weather station measure humidity?

Humidity is measured by a capacitive sensor: a thin polymer film absorbs water vapor from the air, which changes its electrical capacitance. The station converts that change into relative humidity. Capacitive sensors are accurate when new — Davis quotes ±2% RH — but they drift a little over the years, especially at the humid end of the scale.

The humidity element lives in the same radiation shield as the temperature sensor, and for good reason: relative humidity depends on temperature, so both must be measured in the same air. From the pair, the station also derives the dew point — arguably the more useful number for judging how the air actually feels. We compare the two in dew point vs humidity.

Because of that slow drift, humidity is one of the few readings worth sanity-checking every year or two against a trusted reference or a nearby official station.

How does a weather station measure wind speed and direction?

Wind speed is measured by the anemometer: cups that spin on a vertical axis, generating a magnetic or optical pulse with each rotation. The station counts the pulses — rotation speed is proportional to wind speed. Direction comes from a wind vane whose potentiometer or magnetic encoder reports the vane's angle from north, in degrees.

Direction is reported with 0° as north, 90° as east, and so on. Davis anemometers are known for their low starting threshold, so they register light breezes that cheaper cup sets miss. The station samples wind every few seconds: the brief peaks become your gust readings, while longer averages become the sustained wind you see on the dashboard.

Mounting matters enormously here. The meteorological standard is 10 meters (33 feet) above open ground, clear of buildings and trees — a rooftop compromise is fine for hobby use, but every obstruction steals speed and twists direction. Over months, those direction samples accumulate into a wind rose, the chart that shows your prevailing wind at a glance.

How does a weather station measure rainfall?

Rainfall is measured by a tipping bucket rain gauge. A funnel directs rain into one of two tiny buckets on a pivot. When a bucket fills with a calibrated amount — 0.2 mm of rain on metric Davis collectors, 0.01 inch on US ones — it tips, logs a pulse, and swings the empty bucket into place.

Total rainfall is simply the tip count multiplied by the tip size, and the rain rate is calculated from the time between consecutive tips. The design is mechanically simple and very reliable, but it has known quirks: some water is lost mid-tip during intense downpours, and a funnel full of leaves or insects silently blocks the whole measurement.

The mechanism, its failure modes, and how to keep it honest get a full article of their own: how weather stations measure rainfall.

How does a weather station measure barometric pressure?

Barometric pressure is measured by a MEMS sensor: a microscopic silicon diaphragm that flexes as air pressure changes, altering its electrical properties. The pressure sensor lives inside the console or sensor suite rather than out in the weather. The station converts raw station pressure to sea-level pressure so your readings match weather maps.

That sea-level correction is important. Air pressure drops as you go up, so a station at 300 meters elevation reads much lower raw pressure than one at the coast under identical weather. Adjusting to sea level makes readings comparable everywhere, which is why forecasts and weather maps always use it.

Pressure is the one sensor with genuinely predictive value on its own: steadily falling pressure usually signals an approaching system, while rising pressure suggests clearing weather. It is also entirely maintenance-free — there is nothing outside to clean or align.

How do solar radiation and UV sensors work?

Solar radiation and UV are measured by photodiodes, semiconductors that convert light into a tiny electrical current. The solar sensor reports total sun energy in watts per square meter (W/m²); the UV sensor responds only to the ultraviolet band and reports the UV Index, the standard measure of sunburn risk.

Both sensors need a completely unobstructed view of the sky, which is why they sit on top of the sensor suite. Even partial shading for part of the day produces misleading daily totals.

Solar data is more useful than it first appears: it feeds evapotranspiration calculations for irrigation, helps with solar panel planning, and explains those days that felt hotter than the thermometer suggested. On Davis stations, solar and UV are optional sensors — included on the Vantage Pro2 Plus, not supported on the Vantage Vue.

How does the AirLink measure air quality?

The Davis AirLink measures particulate matter with a laser particle counter. A small fan draws air through a chamber where a laser beam illuminates it; particles scatter the light, and a photodetector counts and sizes them. From those counts, the sensor reports PM1, PM2.5, and PM10 concentrations continuously.

The size categories matter for health: PM1 covers particles under 1 micrometer, PM2.5 (under 2.5 µm) is the standard health measure because those particles penetrate deep into the lungs, and PM10 (under 10 µm) captures coarser dust and pollen. Note that the AirLink measures particles only — it does not detect gases like ozone or nitrogen dioxide.

The raw concentrations are usually shown as an index: the US EPA AQI or the European EAQI, which apply different breakpoints to the same measurements. We unpack the differences in AQI vs EAQI.

How does the data get from the sensors to your website?

Each sensor reports to the station's integrated transmitter, which radios readings to your console or WeatherLink Live every few seconds. From there they upload to Davis's WeatherLink cloud, and any connected service — the WeatherLink app, or a hosted website — reads them through the WeatherLink API.

Knowing this chain helps when something looks wrong: a single flat-lined reading points at one sensor, all readings stopping points at the transmitter or its power, and stale data online points at the internet upload rather than the station itself.

Understanding how the sensors work also helps you interpret the data correctly — why temperature creeps high on a calm sunny afternoon, why rain totals run slightly low in a cloudburst, or why wind readings depend so much on mounting height. And if you want all of these sensors on one live, modern website, Pro Weather auto-discovers every sensor attached to your WeatherLink account — AirLink included — and builds the pages automatically. Start a free trial and see your own sensor data in a new way.

Common questions

How accurate are home weather stations?

Quality varies enormously between brands. Davis publishes ±0.3 °C (±0.5 °F) for temperature and ±2% for relative humidity on the Vantage Pro2, which is close to professional-grade; budget stations can be off by a degree or more. In practice, placement errors dwarf sensor errors — a well-calibrated sensor in a bad spot produces worse data than a mediocre sensor in a good one.

Why does my temperature read high in the sun?

On calm, sunny days a passive radiation shield cannot fully vent the heat building up between its plates, so readings can creep a degree or two above the true air temperature. It is almost never a broken sensor. Check what surrounds the shield — walls, paving, dark surfaces — and consider a fan-aspirated shield if your site is frequently sunny and still.

Do weather station sensors need calibration?

Most do not: pressure, solar, and wind sensors hold their calibration for years. The two worth checking are humidity, because the polymer film drifts with age, and the rain gauge, where an unlevel mount or shifted adjustment changes the tip volume. We walk through the checks and adjustments in how to calibrate your weather station's sensors.

How long do weather station sensors last?

Davis hardware routinely runs for a decade or more outdoors. The parts that age are predictable: the humidity element drifts, anemometer bearings eventually add friction (a spin test reveals it), sun-exposed plastics turn brittle, and the transmitter's supercap or battery wears out. All of these are replaceable parts, so an aging station is usually a repair job rather than a replacement.