Purpose
The Climate Extremes Tables display the top ten daily rainfall and temperature records around Australia on any particular day, month, season and year. Highest and lowest daily temperatures are displayed, as well as the highest rainfall totals. The official records of extremes of daily maximum and minimum, and daily rainfall for Australia and each State or Territory for each month, season and year are also displayed. Temperature extremes are available from 1957 to present. Rainfall extremes are available from 1910 to present.
About the data
For daily rainfall and minimum temperature, the observation allocated to a particular day represents the total rainfall recorded or lowest minimum temperature recorded in the 24 hour period from 9 am local time on the previous day to 9 am local time on the selected day. For example, the rainfall allocated to 5 February represents the rain which falls between 9 am local time on 4 February and 9 am local time on 5 February. For maximum temperature, it is the highest temperature recorded between 9 am local time on the day that is selected to 9 am local time on the following day. For example, the maximum temperature allocated to 10 June represents the maximum temperature between 9 am local time on 10 June and 9 am local time on 11 June.
Occasionally there will be a day or month where no rainfall is recorded, or rainfall is only recorded at a small number of sites. When no rainfall is recorded no data will be displayed in the table and when rainfall is only recorded at a small number of sites, only the sites that recorded rainfall will be displayed in the table. Therefore, occasionally no data, or less than ten records will be displayed in the tables.
Quality control of data
The data used to generate these extremes tables arrive at the Bureau of Meteorology through a combination of electronic and postal communication channels. Real-time reports are screened for errors, but are not fully quality controlled until months afterwards. Some of the historical data is likewise not fully quality-controlled, and some errors may appear in these tables. When noticed, tables will be regenerated to remove such erroneous data. Tables for recent days, months and seasons are routinely regenerated to make use of the on-going quality control applied to the underlying data.
The rainfall totals displayed in these tables may have been recorded using either an automated Tipping Bucket Rain Gauge (TBRG) or a manually read rain gauge. At some sites, such as Darwin Airport (Bureau station number 014015), both types of gauge are co-located on the same observing site and report under the same station number. In such cases, the TBRG data, which is reported in real time, will arrive first and be displayed in these tables. At a later point, as the manually read observations are reported, these tables will be updated to reflect these observations as the manually read gauge is the primary instrument and these totals are considered to be of higher quality. At times, it is possible that the manually read totals will be quoted in Bureau products before these values have been processed into the Australian Data Archive for Meteorology, the Bureau of Meteorology's database of weather observations, from which these tables are derived.
Download the Australian daily temperature and rainfall extremes report
To complement the official extremes records displayed on these pages, the Bureau's Australian rainfall and temperature records report is available for downlaoding. This report lists the official extremes for daily maximum and minimum temperature, and daily rainfall, as of the time of writing (February 2009). The report also discusses the factors which influence temperature and rainfall extremes and their geographical distribution in Australia.
Download file [3 MB, PDF]
Disaggregation
The data sets used to create these tables are derived from those used to create the Australian Water Availability Project (AWAP) daily rainfall and temperature analyses (available at http://www.bom.gov.au/jsp/awap/).
Occasionally daily observations are missed at sites, leading to multi-day accumulations when they are finally read a day or two later (for example, a two-day rainfall total). If complete observations exist at one or more nearby sites, it is possible to disaggregate the multi-day accumulation - in other words, to use the pattern of rainfall at the neighbouring site(s) to obtain estimates of daily rainfall which add up to the reported multi-day accumulated total.
In preparing the data sets for the AWAP daily analyses, disaggregation of multi-day rainfall totals is performed where feasible, and the results used in the analyses. In consequence, some of those estimated daily rainfall totals will appear in these tables. Perhaps the most notable of those is the two-day rainfall of 1947.0 mm recorded at Bellenden Ker Top Station (Bureau station number 031141) on 5 January 1979. This two-day total is more than twice the official one-day record of 907.0 mm at Crohamhurst on 3 February 1893, meaning that the 907.0 mm total is known to have been exceeded on at least one of the two days in January 1979. The 907.0 mm total remains the official daily rainfall record because it was actually observed. Estimated daily totals for these two days, along with some other notable examples, are given in the table below.
| Estimated Total (mm) | Day | Site Name | Site Number | Comment |
|---|---|---|---|---|
| 1352.5 | 5 January 1979 | Bellenden Ker Top Station | 031141 | Two-day accumulation of 1947.0 mm observed on 5 January 1979. Disaggregation yields estimates of 1352.5 mm for 5 January 1979 and 594.5 mm for 4 January 1979. |
| 1174.6 | 13 February 1999 | Bellenden Ker Top Station | 031141 | Two-day accumulation of 1870.0 mm observed on 13 February 1999. Disaggregation yields estimates of 1174.6 mm for 13 February 1999 and 695.4 mm for 12 February 1979. |
| 1015.3 | 23 March 1997 | Bellenden Ker Top Station | 031141 | Three-day accumulation of 1400.0 mm observed on 24 March 1997. |
| 454.3 | 20 April 2006 | Bellenden Ker Top Station | 031141 | Two-day accumulation of 623.0 mm observed on 20 April 2006. |
Multi-day accumulated maximum and minimum temperatures also occur from time to time, and these can also be disaggregated in a manner analogous to that used for daily rainfall, provided a suitable neighbouring site has complete observations for the period in question. For multi-day temperature accumulations, the temperature value itself is known, rather, it is the day on which it occurred which is unknown and therefore estimated in the disaggregation process. The other day(s) in the multi-day period are not assigned daily temperature estimates however. The AWAP daily temperature analyses employ this disaggregation technique, and the results may appear in these tables.
Where a station name is preceded by a ^, such as ^ Bellenden Ker Top Station, this indicates that the value for that day has been derived by disaggregation of a multi-day accumulation.
