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 book The Weather Observer’s Handbook (published by Cambridge University Press), 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
The calibration of all barometric pressure sensors, particularly electronic units, should be checked regularly to avoid calibration drift. More details are given in The Weather Observer's Handbook, Chapter 15.
Barometric pressure is the easiest of all of the weather elements to measure, and even basic weather stations or household aneroid barometers can provide reasonably accurate readings. It is also the only weather element that can be observed indoors, making a barometer or barograph – analogue or digital – an ideal instrument for apartment dwellers.
The units of atmospheric pressure are hectopascals (hPa) – a hectopascal is numerically identical to the more familiar millibar. Inches of mercury are still used for some public weather communications within the United States – one inch of mercury is 33.86 hPa.
A once-daily ‘morning observation’ is the best time to read/reset any manual instruments in use, as well as perform visual checks on the operation of the sensors for an automatic weather station AWS, particularly raingauge funnels which are likely to become blocked if left unchecked. A manual observation also provides a convenient opportunity to note current weather details such as the amount and types of cloud, the surface visibility, present weather, the occurrence of lying snow, and so on.
The traditional method of measuring humidity is by using a pair of matched mercury-in-glass thermometers, known individually as dry-bulb and wet-bulb thermometers and in combination as a dry- and wet-bulb psychrometer. The wet-bulb is a thermometer whose bulb is kept permanently wet using a thin close-fitting cotton cap or sleeve. The wet-bulb is cooled by evaporation, and the difference in temperature between dry-bulb and wet-bulb thermometers is a measure of the humidity of the air. Using tables, an online calculator or formulae, the relative humidity (or any of the other humidity measures) can be quickly and easily determined from simultaneous readings of the two thermometers.