Recording the Weather
in Armidale NSW
History
Early settlers on the Northern Tablelands in the early 1800s noticed the
similarity between the climate here and in some parts of England, warm summers
and cold winters with severe frosts and occasional snowfalls, hence the region
gaining the name "New England." Some of these pioneers made their own
temperature and rainfall measurements with claims that temperatures as high as
39 degrees C (102 deg F) had been recorded, and as
low as -12 degrees C (10 deg F).
POST OFFICE - 1857 TO 1965
In the second half of the 19th century the government
commenced setting up a network of weather stations in the main cities and towns
across the country. Post offices were mostly chosen as the sites for these
weather stations with the postmaster being in charge of recordings. In Armidale
the post office, which was located a short distance to the west of the present
building, became the official weather station from December 1857. Daily
readings taken included rainfall, temperatures, wind, pressure and cloud cover.
In 1880 a new post office building was built at the corner of Beardy and
Faulkner Streets where weather recordings continued until 1965.
RADIO STATION 2AD - 1965 TO 1997
Because the area at the back of the post office was gradually being "built
out" the Bureau of Meteorology moved the weather station a distance of
about 100 metres to the back yard of Radio Station 2AD in Rusden Street between
Marsh and Faulkner Streets in July 1965. This was a more open area, and because
the radio station was staffed almost around the clock seven days a week, it was
convenient for staff to keep up the seven observations per day which the Bureau
required.
Recordings continued there until June 1997 when a further move was necessary.
UNE EAST ARMIDALE SITE - FROM 1997
Over the years from 1965 the area around the back yard
of the radio station slowly suffered the same problem as the rear of the post
office. New buildings and bitumen car parks were built. In June 1997 when the
2AD backyard was about to be replaced by a carport and cement carpark, the
weather station was relocated to the site of the University of New England
(UNE) weather station in Mann Street, East Armidale which had been in operation
at this location since October 1980. This was a move of about one kilometre to
an area of slightly lower temperatures and greater incidence of frost, so the
Bureau of Meteorology decided not to amalgamate records from the former and new
sites, but to commence a new set of records at the UNE location. During the 16
years that both stations were operating in parallel maximum temperatures
averaged 1.1 degrees lower and minimums 1.7 degrees lower at the UNE site.
AIRPORT WEATHER STATION - FROM 2001
In 2001 an automatic weather station (AWS) was set up
at Armidale Airport by the Bureau of Meteorology to replace a similar AWS which
had been operated in the same location by the Dumaresq Council since 1993. This
new weather station is completely automatic providing the Bureau with
continuous readouts of temperatures, humidity, rainfall,
pressure, wind, visibility and cloud height.
The airport station is 93 metres higher and five kilometres from the East
Armidale station often resulting in moderate differences in temperatures and
rainfall. Because the airport is on a plateau and the East Armidale station is
in the Armidale valley, the airport overnight temperatures are often around two
to five degrees higher than the city. During the day the airport is windier
than the more sheltered valley causing day temperatures to frequently be about
one degree lower than the city.
Instrumentation at East Armidale Weather
Station
The Bureau of Meteorology weather station is located in East Armidale within
the valley of Dumaresq Creek at an elevation of 987 metres
above sea level.
Temperature
Temperatures are measured with mercury and alcohol thermometers which are read
by observers at designated observation times daily. These thermometers are very
accurate measuring the temperature in tenths of degrees.
They are housed within a Stevenson Screen which is a white painted timber box
with louvred sides with the base about 1.1 metres above the ground. The louvres allow outside air to
move slowly past the instruments while protecting them from direct sunlight,
wind and rain, and temperatures recorded this way are referred to as screen or
shade temperatures.
Mercury thermometers supply current dry and wet bulb temperatures.
A mercury thermometer records the maximum temperature for the 24 hours to
An alcohol thermometer records the minimum temperature for the 24 hours to
A thermograph was in use until
2019 recording the temperature continuously onto a seven day graph which
was used to determine the times at which maximum and minimum temperatures
occurred.
An alcohol minimum thermometer on the surface of the grass records the
overnight terrestrial or grass minimum temperature. The terrestrial
minimum is usually between two and five degrees lower than the screen minimum.
From 2019 temperatures are also recorded by a digital weather station.
Rainfall
Rainfall is recorded with a rain gauge set in the ground with the top 30 centimetres above the ground. It consists of a metal drum
with a funnel 203 millimetres in diameter and a plastic measuring cylinder
within. Rainfall is totaled for the 24 hours ending
Evaporation
This is measured using an American Class A pan 1206 millimetres in diameter and
250 millimetres deep. At
Wind
A wind vane mounted to a ten metre tower is used to
determine the wind direction to 16 points of the compass. A cup anemometer,
also mounted to the tower, is used to calculate the wind speed and the wind run
for the 24 hour period ending at
Cloud
Details of clouds including amount of cloud covering the sky in eighths, height
of clouds, and the type of clouds are observed and recorded.
Visibility
Horizontal visibility is estimated. This is reduced by precipitation, fog, and
on some winter mornings and evenings by Armidale's woodsmoke haze trapped in the valley.
Phenomena
Other aspects of the weather referred to as phenomena are also recorded. These
include: frosts, fogs, hail, snow, thunderstorms and strong winds.
Aerial view of weather station on 10 August
2021 showing location of instruments
Manually operated weather stations, such as the East
Armidale weather station, continue to remain a part of the Bureau of
Meteorology’s network as human observers can observe and report conditions that
automatic weather stations are unable to do, such as details of clouds,
thunderstorms, hail (size and quantity of hailstones) and snowfalls (depth of
snow on ground).
The Bureau, however, is gradually phasing out many of the manual weather
stations, particularly those which are in close proximity to automatic
stations.
East Armidale Weather Station Timeline
July 1980 - Weather
station enclosure constructed (10 x 12 metres) in a
reasonably open area of land used for field studies by the Armidale College of
Advanced Education, formerly the Armidale Teacher’s College.
The location
is bounded by Taylor, Mann, Kennedy and Kentucky Streets. The weather
station is about 80 metres west of a gully known as Black Gully at an altitude
of 987 metres above sea level. The area is on a gentle slope with some trees
nearby, and the station was set up in the centre of a cleared paddock formerly
used to graze sheep. Large Stevenson screen installed.
11 October 1980 - Daily 9am
readings, except on weekends, of temperatures and rainfall commenced.
Thermograph used to determine maximum and minimum temperatures on Saturdays and
Sundays.
2 December 1980 - Ten metre wind
tower erected with wind vane and anemometer mounted at the top. 9am run of
wind, wind direction and wind speed readings commenced.
13 January 1981 - 9am soil
temperature readings commenced at depths of five and ten centimetres.
13 February 1981 - Terrestrial
(grass) minimum temperature readings commenced.
9 July 1982 - 9am soil temperature
readings commenced at depth of 20 centimetres.
22 November 1982 - Evaporation pan
installed. Evaporation readings commenced from 23 November.
26 February 1993 - Soil temperature
readings ceased.
1994 - The Armidale Tree Group set
up its nursery immediately to the north of the weather station with its
boundary fence about twenty metres from the station. A number of trees were
also planted in the general area, which after about ten years had grown tall
enough to probably have some minor effect on wind and evaporation readings.
18 June 1997 - The Bureau of
Meteorology commenced readings at the site. A second Stevenson screen
containing BoM instruments was installed in the enclosure with a team of
observers taking four observations daily at 9am, 12 noon, 3pm and 6pm from this
date.
1 May 2001 - Observation schedule
reduced to twice daily at 9am and 3pm.
2015 - Trees within 40 metres to the
south and east of weather station growing to heights in excess of 18 metres. A row of tea tree along the Tree Group boundary fence within ten
metres north of the weather station growing to heights of around five metres.
1 August 2015 - Observation schedule
reduced to one daily at 9am.
17 September 2019 - Digital weather
station installed with data uploaded to weather website about twice per minute
24 hours per day. Temperatures recorded by this weather station are in close
agreement with manual thermometers (+- 1.0C), however rainfall usually overreads by about 20 per cent, and wind direction and
speed are compromised to some extent due to the height above ground of only 1.5
metres.
The East Armidale Weather Station looking
north on 10 August 2021
Updated 11 August 2021
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