This site provides useful practical information related to global and national weather observing practices and instruments, including independent equipment reviews.
You will find much of the background in my new book The Weather Observer’s Handbook (Cambridge University Press, 2012), details of which can also be found on this site, together with useful links and downloads.
Author, The Weather Observer’s Handbook
A nation obsessed with the weather? Yes, certainly, but which nation?
Tip of The Day
Current local records can often be augmented and compared with historical records from the national climate archives. In many countries, online access and downloads are free or available at a nominal charge.
Raingauges should be exposed with the rim at the national standard height above ground – in the UK and Ireland, this is 30 cm; in the United States, between 3 and 4 feet (90 to 120 cm). Most countries define a ‘standard rim height’ as between 50 cm and 150 cm above ground. Take care to set the gauge rim level, and to maintain it accurately so.
Voluntary observers provide the backbone of most countries observing networks, and tend to do so for many years. There are examples within the UK and the United States of a few individuals completing 70 years or more of high-quality weather records. Without doubt, the longer the record, the more interesting it becomes to look back upon notable events.
Grass and earth temperatures are the most commonly observed temperature measurements, after air temperature. The lowest temperatures on a clear night will be recorded at or close to ground level. Where the surface is covered by short grass, the lowest temperatures are attained just above the tips of the grass blades. The so-called ‘grass minimum temperature’ (or ‘grass min’) is measured using a thermometer or electrical sensor freely exposed in this position. A ‘ground frost’ occurs when the grass minimum falls below 0°C.
Wind direction and speed are normally measured using separate instruments, most often a cup anemometer and a potentiometer-based wind vane. The absolute accuracy of wind speed measurements is more likely to be limited by the height and exposure of the anemometer, rather than the accuracy of the sensor. The accuracy of wind direction measurements depends more upon careful alignment at installation.