There’s an oft-repeated saying that real-estate agents will tell you of the three important factors when it comes to property: location, location, location. When it comes to setting up instruments to measure the weather, the refrain could be similar: exposure, exposure, exposure.

It is certainly true that a well-exposed budget AWS will give more representative and reliable statistics than a poorly exposed top-of-the-range AWS costing as much as a small car. However, a garden the size of New York’s Central Park is not a prerequisite to making worthwhile weather observations, because by taking some care in siting your sensors and following the advice in this chapter, good results can be obtained from all but the most sheltered locations.

Firstly, what is meant by site and exposure? The two terms are often used synonymously, but in this book site is normally used to refer to ‘the area or enclosure where the instruments are exposed’, while exposure refers to ‘the manner in which the sensor or sensor housing is exposed to the weather element it is measuring’.