About days of rain maps

How were the maps created?

Rainfall data are recorded at a network of weather stations across Australia. The data from these weather stations are stored electronically in the Bureau of Meteorology's database called ADAM (Australian Data Archive for Meteorology).

The average rainfall maps were based on daily rainfall data from about 3500 weather stations. The daily data were extracted from ADAM and a number of quality control checks were then applied to the data. For example, the data were checked for missing values over the length of the data record.

After the quality checks were applied to the data, a count of days above each threshold was undertaken. Monthly and annual averages were calculated for each of the weather stations for each threshold. An objective analysis technique was then applied to these station averages to produce regular gridded datasets (each month and annual) covering Australia.

Finally, the gridded data were visualised in a geographic information system and the colour maps created through this process.

Stations used in the analysis

Daily rainfall data from about 3500 weather stations across Australia were used to create the days of rain maps. These stations are shown in the map below.

recording stations used in the avrerage annual and monthly days of rain analysis

Days of rain metadata

The following metadata summary, and detailed metadata file, provide information about the average monthly and annual gridded days of rain datasets. For example, information is provided about the format, spatial extents and analysis techniques used to generate the grids.

TITLE: Mean monthly and annual number of rain days data
DESCRIPTION: Mean monthly and annual number of days of rain grids. The grids show the days of rain values across Australia in the form of a two-dimensional array. The indices are based on the standard 30-year period 1961-1990.
CUSTODIAN: Bureau of Meteorology
AVAILABLE FORMAT TYPE(S): ASCII row major, Arc/InfoTM grid export(.e00), Shapefiles.
SCALE/RESOLUTION The resolution of the data is 0.025 degrees (approximately 2.5km)