A weather station is an instrument used to observe atmospheric pressure with a view to predicting the likely weather that will follow within the local area. Essentially they are used to forecast the weather, as well as providing accurate local temperature readings, but their functions and accuracy vary dramatically, and are influenced by a number of variables, most notably placement which is key to reading microclimates accurately.
A typical model may measure temperature via a thermometer, atmospheric pressure via a barometer, humidity via a hygrometer, wind speed via an anometer, and in some cases come with a rain gauge to measure rainfall.
The barometer is arguably the most important feature, and may be the only feature of some models. It tracks both the rise and fall of the local air pressure and provides, based upon those changes, an indication of whether the weather is likely to get better or worse.
In terms of personal stations, as opposed to professional stations used in industry, there are two types available. First there are lenders who measure the air pressure to provide their forecasts. A forecaster will generally come with the ability to indicate temperature both indoors and outdoors thanks to a wireless sensor. The wireless sensor can be placed just about anywhere, at the end of your garden for example, and transmits information back to the central location where your weather station is based via a radio frequency. In most cases the wireless sensor can be placed up to 100 meters from the base unit provided there are no obstacles, such as a wall, in the way. Specifications vary so this is something that should be checked before purchasing a weather station. It is, in some cases possible to run a cable sensor from the weather station allowing the sensor to be placed two or three hundred meters from the base.
Forecasters further up the scale offer a feature providing an indication of air pressure over a period of up to three days, which is popular when combined with a weather forecast feature. They may also include a system enabling you to set an alarm within set parameters (temperatures) which is useful if you grow plants, fruit and vegetables, or sometimes suffer when the temperature reaches certain extremes. The high end forecasters come with a plethora of features which are capable of drawing upon data from several sensors and producing more accurate predictions, as well as displaying recordings in a user friendly way.
The other option is an all inclusive weather station which, in addition to measuring air pressure, will come fitted with the other measuring devices mentioned above to take in readings for temperature, humidity, wind speed and precipitation. They are capable of recording and retaining large volumes of information which can be downloaded onto a personal computer or viewed on the unit's display.
To power a personal weather station all that is required is a set of standard batteries or a lead connecting to the mains, depending upon the make and model.
There are several reputable manufacturers who currently produce a wide range of weather stations to suit all needs and budgets.