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How to read AWN's Daily Climatic Data for the month

Daily data for the month brings together on one page all of your weather district's daily rainfall, temperature and other climatic information for each of the past 12 months. There's also a link to an archive which goes back to the beginning of climatic records.

Use the links at the top of each district page to access data for the past 12 months.

Data reliability and availability: The data is sourced from the Bureau of Meteorology real-time systems, using a mixture of synoptic reports and data received daily by AWN from the National Climate Centre. Most of the data are generated and handled automatically. Some quality checking has been performed, but it is still possible for erroneous values to appear. Take care in using the data, and if something looks unusual, be sure to make comparisons with nearby stations on the same day. From time to time, observations will not be available, for a variety of reasons. Sometimes when observations are missing, the next value given has been accumulated over several days rather than the normal one day. Where the observer has noted this, the number of accumulated days is shown as a superscript, so a rainfall reading of 34.62 lets you know that the 34.6mm fell over 2 days.

Updates: Tables for the current month are updated several times each day. Tables for past months are updated periodically with late rainfall returns (many of the Bureau's voluntary rainfall observers only send in their reports at the end of each month) and quality controlled data. The time of preparation of each table is shown at the foot of the page.

Colour coding and extremes: Colour coding helps you to quickly identify warm, cool, wet, windy, sunny, dull and other periods of exceptional weather. Extreme highs and (in most cases) lows are identified by a black box. The format lets you easily compare the readings across stations for the same day, or across days for the same station. An alternative station-by-station presentation of this data is available from the Daily Weather Observations section of the Bureau of Meteorology's website.

Column heading

Description

Station details

This line gives the official Bureau station title, and the station's altitude, latitude and longitude. It also gives the distance and direction of the station from the nearest well-known town.

Element

Rain = the rainfall to 9am in millimetres
Max = the maximum air temperature in °C for the 24 hours from 9am (but see below)
Min = the minimum air temperature in °C for the 24 hours to 9am
Gr Min = the grass or terrestrial minimum temperature in °C for the 24 hours to 9am
Evap = the evaporation measured for the 24 hours to 9am in millimetres
Sun = the number hours of bright sunshine recorded for the day (midnight to midnight)
Gust = the maximum wind gust for the day (midnight to midnight) in km/h, with the hour in which it occurred shown as a superscript
Wind>3m, Wind <3m= the total wind run in kilometres for the day to 9am measured by an anemometer higher or lower than 3m
Soil10, Soil20, Soil50 = Soil temperature in °C at 9am measured at depths of 10, 20 and 50cm
Weather = reported weather phenomena from manned stations: d=dust, f=fog, g=gale, h=hail, s=snow, t=thunderstorm

Norm

This is the monthly average. For maximum and minimum temperatures, this is the long-term mean for the station for this month. For rainfall, it is the average total for the month. For evaporation, sunshine and wind run, it is the long-term daily average. For soil temperatures, it is the monthly average at 9am. Averages are given for all stations with 10 years record for the month and element. However, because the widespread recording of wind by automatic weather stations is in its infancy, I have given wind averages for stations with at least 5 years data. Stations without a long enough record (10 or 5 years) show N/A in the Norm column

To date

This is the average or total for the month to date. In the tables for previous months, this is the final rainfall total or temperature average for the month. Remember that these totals and averages may be taken from unchecked daily data, and that missing observations may cause significant errors in rainfall totals. The odd gap is less worrisome in temperature records.

Rain

Rainfall is given for the period to 9am. The period is normally 24 hours, but some stations may report over longer periods (typically 48 or 72 hours), especially over weekends. A report such as 23.43 indicates that 23.4mm was recorded over 3 days. "--" indicates that no report was received on this day, so there may have been no rain, or rain on this day may be included in the next total to the right, or the reading may have been missed altogether.

The rainfall cells turn deeper shades of green to draw attention to heavier totals, regardless of the period in which they were recorded:

25.0 to 49.9mm

50.0 to 99.9mm

100.0mm or more

Max, Min and Gr Min Temperatures

The maximum and minimum air temperature and minimum grass temperature cells change colour to highlight variations above or below average. Where the station has been operating long enough to have credible means (shown in the means column), the colour shows the variation above or below this figure. Where there are no long-term means, the variation is taken from the average so far this month.

4 to 7.9 degrees above normal

4 to 7.9 degrees below normal

8 to 11.9 degrees above normal

8 to 11.9 degrees below normal

12 degrees or more above normal

12 degrees or more below normal

The maximum temperature is the highest temperature recorded between 9am on the date shown and 9am the next day -- the official period for the measurement of the maximum temperature in Australia. An interim measurement is provided by stations at their 3pm observation, and this is overwritten with the official figure the next day. The maximum usually occurs on the date given in its column, however it's not uncommon when a cool day is followed by a warm one for the maximum to be set at 9am the next day. For example, say the temperature on the 7th April only reaches 15° during the early afternoon of the 7th but rises to 17° by 9am on the 8th April. It will appear in the tables as 15 when the pages are produced for the 7th April but will be updated to 17 when the pages are next updated on the 8th April.

The minimum and grass minimum temperatures for all days are for the 24 hours to 9am on the date shown.

Evap

Evaporation is the amount of water lost through evaporation from a standard evaporation pan for the 24 hours to 9am. Like rainfall, the period is normally 24 hours, but some stations may report over longer periods -- a report such as 23.43 indicates that 23.4mm evaporation occurred over 3 days. "--" indicates that no report was received on this day, so there may have been no measurement, or evaporation on this day may be included in the next total to the right, or the reading may have been missed altogether.

The evaporation cells turn different shades to draw attention to greater or lesser totals, regardless of the period in which they were recorded:

more than 25% above average

more than 25% below average

within 25% of average

Wind<3m
Wind>3m

Wind run is given for the 24 hours to 9am. Wind run is the total amount of wind to pass the anemometer over the 24 hour period, so division by 24 gives the true average windspeed for the period. The >3m observations are normally made at the standard height of 10m, and are fairly comparable between stations as they are not affected by nearby obstructions. The <3m observations are normally made in conjunction with evaporation readings, and the anemometer is only about 2m above ground level. On rare occasions at manned stations an observation may be missed and two or more days wind run may be accumulated, as with rainfall.

The wind run cells turn different shades to draw attention to greater or lesser totals, regardless of the period in which they were recorded:

more than 25% above average

more than 25% below average

within 25% of average

Gust

This shows the maximum wind gust in km/h recorded in the 24 hours midnight to midnight, and the hour in which it occurred. For example, 10415 indicates that the top gust for the day was 104km/h occurring between 3pm and 3.59pm local time.

The wind gust cells turn different shades to draw attention to gusts of gale or storm force:

storm force (90km/h or greater)

gale force (63 to 89km/h)

below gale force (below 63km/h)

Sun

Sunshine is measured by a standardised sunshine recorded, normally a glass sphere that concentrates the sun's rays onto a waxed sheet of paper, burning a trace on the paper when the sun is strong enough. The traces are totalled by the observer at the end of the day. Because weak sunshine may not burn the paper, the measurement is said to be of bright sunshine.

The sunshine cells turn different shades to draw attention to sunny or dull days:

6 hours or more

2 to 5.9 hours

less than 2 hours

Soil10
Soil20
Soil50

Soil temperature is measured several times daily and at different depths. These figures, taken at depths of 10, 20 and 50cm, are for 9am each day.

The cells change colour to highlight variations above or below the average so far this month.

Within 2°C of normal

8 to 11.9 degrees above normal

2 to 3.9 degrees below normal

12 degrees or more above normal

12 degrees or more below normal

Weather

This is a somewhat rough-and-ready summary from manned stations of any major weather phenomena for the day, midnight to midnight:
d=dust (either a duststorm or dust in widespread suspension in the air
f=fog (visibility less than 1km)
g=gale (sustained wind of 63km/h or more at some time during the day)
h=hail (either from thunderstorms or wintry showers
s=snow
t=thunderstorm

Unfortunately, often for valid reasons, not all observers are equally assiduous in completing this section of the field book into which observations are entered so the absence of one of the code letters is no guarantee that that phenomenon did not occur. In order to improve this situation, AWN scans all synoptic reports from all stations daily, and adds any dust, fog, gale, hail, snow or thunderstorm reports from the 3-hourly observations to this summary.