Automatic weather stations (AWS) provide frequent near continuous reports, with AWN showing the main ones every 30 minutes. In addition, we show special reports whenever certain conditions are met, such as sudden temperature falls or rises, heavy rainfall or changes in wind direction or strength. The reports given on AWN include the full Bureau of Meteorology network (which have a six-digit site Id number in the left column) and a selection from private networks (where the last three characters of the site Id number are letters). Reports from non-Bureau sources may not meet Bureau standards.

Most of the items reported are pretty obvious, but you may need help with the following columns:

Wind: The first figure given in the sustained or average windspeed over the past 10 minutes. The second is the strongest gust recorded over the past 10 minutes.

Visual observations: Visibility, cloud and weather are known as visual observations because they used to be made by a human observer using his or her eyes. They are critical observations for aviation. Since 1996 the Bureau has progressively introduced automatic visibility meters and ceilometers which automatically measure cloud amounts and bases to about 130 of the total 650 AWSs in Australia. While the type of weather that is occurring at fully automatic AWSs is not reported, it can usually be deduced from other readings, e.g. if visibility is below 1000m then there is fog, and if there is rain in the "past 10 mins" column it is likely to be raining.

At some of the busiest airports, a Bureau staff member still feeds two lots of additional information into the AWS data before it is sent off to the Bureau: the types of clouds associated with each level and the types of weather occurring at the airport. In our tables, this human data is marked with an asterisk (*) in the visibility column while sensor data is not.

Visibility: is given in metres, so 7000 = seven thousand metres = 7km.

Cloud cover: Up to three levels or layers of cloud can be reported. For each level, the cloudbase and the amount of sky covered by that layer are given. If it is a human observation, the cloud type is also given. For example, SC 390st BR 900sc tells us there are two cloud layers. The first is SCattered stratus with a cloudbase of 390 metres. The second is BRoken stratocumulus with a base 900m above ground level. A report of SC1260 means scattered cloud with a base of 1260m or 1.26km - in this case no cloud type shown so it is a sensor observation. The codes are:

Weather: At busy airports manned by Bureau staff, the type of weather occurring at the time of observation is given in the code below. Up to two types of weather can be reported simultaneously, such as fog and rain. Each type of weather can further be broken down by its intensity and character. So mdShRA is moderate showers of rain, diTsRA is distant thunderstorm with rain and hvTsHL is a heavy thunderstorm with hail. Elements may be omitted, such as di//DD (distant dust devils) or lt//RA (light rain). The codes are:

23/08/16