A thermometer measures air temperature by detecting the thermal energy in the surrounding air. Modern digital thermometers use electronic sensors — typically thermistors or platinum resistance thermometers — that change electrical resistance with temperature. Mercury and alcohol thermometers use the thermal expansion of a liquid in a sealed glass tube.

For outdoor weather measurement, the thermometer must be shielded from direct sunlight and radiated heat from buildings and pavement. A radiation shield — a louvred white enclosure that allows air to circulate freely while blocking solar radiation — is standard in all home weather stations. Without one, a thermometer can read 5 to 15°F higher than the true air temperature on sunny days.

For home use: See our best outdoor thermometers guide for standalone options, or choose a home weather station that includes an integrated shielded sensor.

A barometer measures the weight of the atmosphere above the measurement point. Atmospheric pressure changes as weather systems move in and out — falling pressure indicates an approaching low pressure system bringing cloud, wind and rain; rising pressure indicates a high pressure system bringing clearer, calmer conditions.

The trend matters more than the absolute reading. A rapid pressure drop of 0.10 inHg or more over three hours is a reliable indicator of deteriorating weather. Most digital home barometers display a trend arrow alongside the current reading, and the better weather station apps plot pressure over 24 hours so you can see the rate of change clearly.

For home use: See our best home barometers guide. Standard sea-level pressure is 29.92 inHg (1013.25 hPa) — your barometer reading will be lower at elevation.

An anemometer measures wind speed by detecting the force or movement of air. The most common consumer type uses three hemispherical cups mounted on horizontal arms that spin on a vertical shaft. Wind causes the cups to rotate faster, and the rotation rate is converted to a wind speed reading. Ultrasonic anemometers — used in the WeatherFlow Tempest and Ecowitt Wittboy Pro — measure wind speed by detecting the time difference between ultrasonic pulses sent in opposite directions. They have no moving parts and do not freeze in winter.

The NWS standard for wind measurement is 33 feet (10 metres) above open, flat terrain. At lower heights, buildings and trees create turbulence that significantly reduces measured wind speeds compared to true conditions. Mounting height is the single biggest factor in anemometer accuracy.

A wind vane — also called a weather vane — is an instrument that rotates to point into the wind, indicating the direction the wind is blowing from. Wind direction is reported as the direction the wind comes from, not the direction it is blowing toward. A north wind blows from the north toward the south.

In most home weather stations, the wind vane and anemometer are combined in a single unit. Digital stations convert the vane position to compass degrees (0 to 360) or cardinal directions. Wind direction is one of the most useful indicators of incoming weather — in the northern hemisphere, winds shifting from south to southwest often precede warm fronts, while a shift to northwest typically indicates clearing conditions after a cold front passes.

A hygrometer measures relative humidity — the amount of water vapour in the air expressed as a percentage of the maximum amount the air could hold at that temperature. Modern digital hygrometers use capacitive sensors that change electrical properties as they absorb or release moisture from the surrounding air.

For outdoor weather measurement, humidity affects how temperature feels (the heat index), dew point calculations, and precipitation formation. For indoor use, the ideal range is 40 to 60% RH. Below 30% causes dry skin and respiratory irritation. Above 60% encourages dust mite activity and mould growth.

For home use: See our complete hygrometer guide, our best bedroom hygrometer picks, and our best greenhouse hygrometer recommendations.

A rain gauge measures the amount of liquid precipitation that falls over a set period. The most common consumer type is the tipping bucket gauge: rain falls into a small funnel and fills a see-saw bucket that tips when it holds a set amount (typically 0.01 inches). Each tip registers one count, and the total tips are converted to a rainfall measurement.

Placement is critical. The gauge needs clear, open sky above it with no obstructions within a 45-degree angle from the top. Trees, roof overhangs, and buildings all deflect rain and cause under-reporting. The Aerocone collector used in Davis Instruments stations reduces turbulence at the gauge opening for better accuracy in high-wind rain events.

For home use: See our best rain gauges guide for standalone options and a full comparison of tipping bucket designs.

A pyranometer measures the intensity of solar radiation reaching the earth’s surface from the entire sky hemisphere, expressed in watts per square metre. It tells you how much solar energy is available at your location at any given moment.

For most home weather observers, a pyranometer is an optional addition. It becomes more useful for solar panel monitoring, greenhouse management, agricultural planning, and evapotranspiration calculations for irrigation. The Davis Vantage Pro2 Plus includes a solar radiation sensor as standard. It can be added to the standard Pro2 and to most Ecowitt stations as an optional sensor.

A home weather station integrates most of the instruments above into a single outdoor sensor suite that transmits wirelessly to an indoor console or phone app. A typical consumer weather station measures temperature, humidity, atmospheric pressure, wind speed, wind direction, and rainfall simultaneously.

See our full home weather stations comparison for a complete breakdown of all options.