How Weather Station Sensors Work: Temperature, Wind, Rain, and More

A modern weather station like the Davis Vantage Pro2 or Vantage Vue is a collection of sensors packed into a single unit. Each sensor measures a different aspect of the weather, and together they give you a complete picture of your local conditions.

This guide explains how the main sensors work in plain language, without getting lost in the technical details.

Temperature and humidity

Temperature is measured by a small electronic sensor whose output changes with temperature. Some stations use a thermistor (a resistor whose resistance varies with heat), while current Davis stations use a digital silicon sensor that outputs a temperature reading directly. Whichever type, it is housed inside a radiation shield (the white louvred plates you see on the station) to block direct sunlight, which would otherwise cause artificially high readings.

Humidity is measured by a capacitive sensor. A thin polymer film absorbs water vapour from the air, which changes its capacitance. The sensor measures this change and calculates the relative humidity. These sensors are accurate but can drift over time, which is why periodic calibration is recommended.

Wind speed and direction

Wind speed is measured by the anemometer (the spinning cups at the top of the station). As the cups rotate, they generate pulses (either magnetic or optical) that the station counts. The speed of rotation is proportional to the wind speed. Davis anemometers are known for their low starting threshold, meaning they detect very light breezes that cheaper stations miss.

Wind direction is measured by a wind vane mounted alongside the cups. The vane contains a potentiometer or a magnetic encoder that reports the angle of the vane relative to north. Direction is reported in degrees, where 0° is north, 90° is east, and so on.

The anemometer should be mounted as high and clear of obstructions as possible for accurate readings. The standard recommendation is 10 metres (33 feet) above ground, clear of buildings and trees.

Rainfall

Rainfall is measured by a tipping bucket rain gauge. Rain falls into a small funnel that directs water into one of two tiny buckets balanced on a pivot. When one bucket fills to a calibrated amount (0.2 mm on metric Davis gauges, or 0.01 inch / 0.254 mm on the US version), it tips, emptying that bucket and positioning the other bucket under the funnel. Each tip generates a pulse that the station counts.

The station tracks the number of tips and calculates the total rainfall and the rain rate (how fast it is falling). Tipping bucket gauges are mechanically simple and reliable, but they can undercount during very heavy rain (when some water spills during the tip) and can be affected by debris or insects in the funnel.

Barometric pressure

Pressure is measured by a barometric pressure sensor inside the main console or sensor suite. These are typically MEMS (micro-electro-mechanical systems) sensors: tiny silicon diaphragms that flex with changes in air pressure, changing their electrical properties.

The station reports the raw pressure and also calculates the sea-level pressure (adjusted for your elevation), which is what you see on weather maps and forecasts. A falling pressure generally indicates approaching storms, while rising pressure suggests improving weather.

Solar radiation and UV

Solar radiation is measured by a silicon photodiode that converts sunlight into an electrical current. The sensor measures the total solar energy in watts per square metre (W/m²). This data is useful for evapotranspiration calculations, gardening, and solar panel planning.

UV (ultraviolet) radiation is measured by a UV photodiode that responds specifically to the UV portion of the spectrum. It reports the UV Index, which is the standard measure of sunburn risk.

Both sensors require a clear, unobstructed view of the sky and are typically mounted on top of the sensor suite.

Air quality (AirLink)

The Davis AirLink sensor measures particulate matter (PM) using a laser particle counter. A small fan draws air through the sensor, where a laser beam illuminates any particles. A photodetector measures the scattered light, and the sensor calculates the number and size of particles.

It reports PM1 (particles under 1 micrometre), PM2.5 (under 2.5 µm, the standard health measure), and PM10 (under 10 µm). The readings can be displayed as either the European EAQI index or the US EPA AQI index, which use different breakpoints for the same raw data.

Putting it all together

Each sensor sends its data to the station's console or transmitter, which relays it to WeatherLink. From there, a service like Pro Weather collects it and presents it on your website with live conditions, charts, and records.

Understanding how your sensors work helps you interpret the data correctly: why temperature might read high on a calm sunny day, why rain totals can be slightly off in a downpour, or why the wind reading depends so much on mounting height.

If you have a Davis station and want to see all these sensors on a live, modern website, Pro Weather auto-discovers every sensor in your account and displays them automatically. Start your site and see your data in a new way.