Northern Territory in 2012: Hot days, cool nights and dry.

  • A dry start with a sluggish North Australian Monsoon
  • A dry and cool winter for the south
  • Cool nights but a hot and humid build up in the north

A dry monsoon season for the Top End

Amid a La Niña year, the start of 2012 was one of the driest on record. Many stations across the Top End were nearly 200 mm below the long-term monthly average by 20 January. However, an active monsoon burst halfway through January brought totals up to average. The dry conditions seen in early January quickly returned and persisted throughout most of February with most stations north of Alice Springs receiving well below their average rainfall.

A cool dry season

The 2012 dry season (May to September) was exceptionally cool in the Top End and very dry across the southern NT. A strong sub-tropical ridge was the dominant climate driver throughout the season, blocking troughs and cold fronts from reaching the southern NT. These high pressure systems also pushed cool and dry air into the Territory allowing for cool days and cold nights and several minimum temperature records were set. Widespread fog patches were recorded during the dry season, especially along the northern coastal areas in the Top End with the Darwin Airport registering 21 days of fog in total. Darwin Airport recorded 85 nights in which temperatures dropped below the 20 °C mark. This is far below the record set by the previous dry season in 2011 of 94 nights, but well above the mean, which is 51.

Bushfires in the Northern Territory

After two wet years in a row, high fuel load had accumulated, and combined with dry and gusty southeasterly winds raised the fire danger index (FDI) across the Territory during the dry months. Fire danger was also raised through the passage of shallow weak troughs propagating eastwards across the southern Northern Territory during these months. There were 3 events in which the FDI reached "extreme" in the NT.

Significant fires were reported in every month of the dry season, with the months of August and September particularly bad in the Top End and throughout the red centre. A total of 52 fire ban days were issued by fire authorities during the season for various Fire Protection Zones across the Territory.

Rainfall

Averaged as a whole, the Northern Territory recorded an average rainfall of 515.7 mm, slightly below the historical average of 540.2 mm. This value is well below the previous two years in which the area average rainfall for the Territory surpassed the 900 mm mark due to the effect of two consecutive La Niñas. This is the driest year since 2005 and the 5th driest in the last two decades. Across the north, the wet season was a typical wet season, with long dry periods interspersed by short but very wet, bursts. Across the south, there was a lack of rain bearing systems during the winter months which led to 157 consecutive days without rain at Alice Springs Airport, their longest dry spell on record. Although many stations received over two metres of rain in the previous two years and three even exceeded three metres, only one station in the Northern Territory managed to break through the two metres mark this year, Labelle Downs with 2098.9 mm up to November 30th.

The eastern Top End was exceptionally dry this year with Warruwi, Groote Eylandt Airport and Alyangula all recording their driest year on record. With 341.8 mm of rain, Warruwi only received 32% of their annual rainfall, which usually exceeds the one metre of rainfall in a year. Gove Airport finished the year with only 1001.6 mm, making 2012 the third driest year on record, far below the average rainfall of 1456.1 mm.

There was a different story for Darwin, where it was felt to be drier than average. However, the long dry periods were interspersed by short but very wet outbursts which brought the total to 1723.2 mm, which is near the long term average of 1729.3. Further south, Alice Springs Airport received 209.4 mm, 74% of their annual rainfall.

Temperature

The average temperature (minimum and maximum together) for the Northern Territory was 0.3 °C below average. This was driven by exceptional cool nights experienced throughout the year Territory-wide. 2011 was cooler, however, with both days and nights below average.

Daytime temperatures were generally up to a degree warmer than average, associated with the lack of cloud cover this year in the far north and far south. The area average maximum temperature for the Northern Territory was 32.1 °C, which is 0.2 °C above the norm. This year had the warmest days on average since 2009, just before the two consecutive La Niñas. Darwin Airport’s mean daytime temperature was 32.3 °C, just 0.3 degrees above the norm, making it the 16th warmest. The warmest on record was 32.9 in 1998, a year with the strongest El Niño of the 20th century. Further south, Alice Springs had a mean daytime temperature of 29.6 °C, 0.9 °C above the norm and its 12th warmest year on record. The exception to this was central parts of the Northern Territory where some stations recorded average daytime temperatures up to a degree below the norm. Elliot had a mean daytime temperature of 33.5 °C, 1.1 °C below the norm, and its 4th coolest year since 1981.

Territory wide, night-time temperatures were generally cooler than average, up to 2.5 degrees below the norm in the central region of the NT. The exceptions to this were some areas in the southeastern Alice Springs and Coburg Peninsula regions, where night-time temperatures were slightly above the norm. The area averaged minimum temperature for the Northern Territory was 17.7 °C, which is 0.8 °C below the norm and the 11th coolest yearly night-time temperatures on record. Darwin Airport, with a mean minimum of 22.5 °C, was 0.7 °C below the norm, the 8th coolest year since records began in the early 1940s. Nights in the Darwin rural areas were a bit cooler at 19.6 °C, 1 °C below the norm and the second coolest since records began in 2002. Across the south, Alice Springs registered a mean night-time temperature of 11.4 °C, 1.1 °C below the norm and 8th coolest on record. Yulara, with a mean night-time temperature of 12.9 °C (1.1 °C below the norm) had its 3rd coolest minimums on average since records began in 1985.

Wind

The strongest wind gust anywhere in the NT this month was at Tennant Creek Airport with 117 km/h from a thunderstorm on January 23rd. These ties the record for strongest wind gust ever recorded at Tennant Creek Airport. The record of a 117 km/h wind gust, originally set on 15 January 1986, was also experienced on 4 January 2004.

The second strongest wind gust was at Cape Wessel with 100 km/h on 17 March and then by Alice Springs Airport with 96 km/h on 7 January.

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Extremes in 2012
Hottest day45.3 °C at Walungurru on 24 Dec
Warmest days on average 35.0 °C at Timber Creek
Coolest days on average28.4 °C at Arltunga
Coldest day 13.2 °C at Arltunga on 2 Jul
Coldest night -5.2 °C at Alice Springs Airport on 7 Jul
Coolest nights on average 11.9 °C at Alice Springs Airport
Warmest nights on average 25.2 °C at Cape Don
Warmest night31.2 °C at Walungurru on 25 Dec
Warmest on average overall 28.6 °C at Cape Don
Coolest on average overall20.3 °C at Arltunga
Wettest overall1885.0 mm at Walker Creek
Driest overall67.0 mm at Bond Springs Turnoff
Wettest day 287.0 mm at Mallapunyah on 27 Jan
Highest wind gust 117 km/h at Tennant Creek Airport on 23 Jan

Maps
ObservedAnomalyDecile rank
Total
rainfall
Map of Rainfall totals Map of Percentage of normal rainfall Map of Rainfall deciles
Mean
daily
maximum
temperatures
Map of Mean maximum temperature Map of Anomaly in mean maximum temperature Map of Decile rank of mean maximum temperature
Mean
daily
minimum
temperatures
Map of Mean minimum temperature Map of Anomaly in mean minimum temperature Map of Decile rank of mean minimum temperature

Click on a map to show it full size in a pop-up window


Month by month
January the first two weeks marked the driest start to any year for most locations in the NT, especially locations along the north coast. By the 20th of the month most of the Top End was nearly 200 mm below the long term monthly average. But as the monsoon trough moved over in the last part of the month many stations received their average January rainfall within just a few days, especially in the western Top End.

  • After a long break, monsoon returns to Top End
  • Yulara sees coolest January on record
  • Darwin Airport sees 10 consecutive days without rain
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
Rainfall rank Maximum temperature rank Minimum temperature rank
February was marked by a prolonged break in the North Australian Monsoon. Nearly all stations north of the Alice Springs District reported below average rainfall for the month. Darwin Airport had a mean maximum temperature of 32.8 °C for the period of 1 December through 29 February. This is 0.9 °C above average and the 3rd hottest 'summer' period on record.

  • Dry conditions continued across the Top End
  • Darwin Airport: 3rd hottest 3 month period (December--February)
  • Tindal RAAF sets several temperature records
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
March 9, saw a tropical low form within the monsoon trough over the Timor Sea. Over the next few days the system, designated as 17U, slowly intensified. While the storm trekked across the Top End, several daily rainfall records were set. In addition to heavy rainfall, strong winds lashed the northwest coast, Darwin Airport for example, measured a wind gust of 85 km/h on the 15th.

  • Cloudband brings heavy rains to the Alice Springs District
  • The North Australian Monsoon returns to the Top End
  • Palmerston sets new March daily rainfall record
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
April for several days the temperature lingered above 36 °C from the 1st to the 5th of the month. These five days set a new April record at Alice Springs Airport for the most consecutive days above 36 °C. For three days (2nd to the 4th), the maximum temperature reached 38 °C which is also a record hot spell for April.

  • Record max temperatures in Alice Springs District
  • Darwin has coolest April night in 43 years
  • Tropical low brings rainfall to north coast
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
May marks the official beginning of the dry season conditions across tropical Australia. A series of high pressure cells in the Bight directed cool, dry and windy southeast winds across most parts of the Territory throughout the month. This southeasterly burst brought low temperatures to the NT with a few records observed.

  • Rain eases in the north
  • Dry season arrives in Top End
  • Darwin Airport coolest daytime May in 31 years
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
June minimum temperatures across the NT were noticeably cool with the area averaged minimum temperature ranking as the second lowest on record. Over the south, many sites failed to register any rainfall throughout the month.

  • Fire Danger Index (FDI) in the Top End reached severe levels for the first time in 2012
  • Dry conditions in the south
  • Cool nights throughout the Territory
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
July dry and cool conditions prevailed over most of the NT. Alice Springs continued to experience below average night-time temperatures almost throughout July (only two nights saw minimum temperatures above the monthly average of 4.1 °C). Throughout July, the Alice endured 19 nights below 0 °C, this is just shy of the record set in 1977 with 20 nights. Darwin experienced cool nights and mild daytime temperatures. At Darwin Airport the temperatures dropped below 20 °C in 22 occasions.

  • 3rd lowest July minimum temperatures for NT
  • 2nd coldest month on record at Alice Springs
  • Yulara Aero ties coldest July on Record
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
August the first signs of transition to the wet season were evident. Early in the month, a typical dry season synoptic pattern brought cold, dry air across the Northern Territory. Indicative of this, were several stations recording record low temperatures. Morning fogs were present along the Top End on 7 days, while the hotter winds kept minimum temperatures higher in the Alice.

  • Darwin Airport records lowest August temperature in 22 years
  • Alice Springs' second longest dry spell on record
  • Bradshaw sets new record for lowest August temperature
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
September is usually the last month of the dry season with an increase in temperatures and humidity across the Northern Territory. Typically in September, the sub-tropical ridge weakens and the climate transitions into the wet season. This month was strongly influenced by the sub-tropical ridge as no rainfall was recorded until the last two days of the month.

  • Dry spell in Alice Springs District ends with 157 days without rain
  • Bushfires char NT
  • "Build Up" is felt in Top End
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
October 24, at 14:30 hours, the temperature at the Alice Springs Airport reached 41.7 °C, equaling the previous hottest October day record set on 18 October 2002. On the morning of Sunday the 29th, a slow moving trough crossed over the western Top End. The rainfall was a classic example of very localised heavy rainfall over Darwin. Leanyer managed to pick up 110.8 mm, their highest October daily total in 23 years worth of records. The city and the Airport, however, failed to received such high values.

  • Below average rainfall across the Territory
  • Hot days across the south and the Top End
  • Relatively cool nights throughout
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
November dry conditions dominated most of the Arnhem and the Roper - McArthur Districts. Gove Airport failed to register any rainfall during this month, making it the driest November since 1994. Farther south, Boroloola received 13.8 mm, their lowest November rainfall since 2006. With a mean daytime temperature of 36.7 °C (third highest November on record) and a mean night-time temperature of 20.2 °C (also third highest), Alice Springs endured its second hottest November with a mean temperature of 28.5 °C, just 0.6 °C shy of the record set in 1987.

  • Very dry conditions over the northeast and southwest
  • Oenpelli's driest November since 1965
  • Second warmest November for the Territory in over two decades
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
December on December 6th and 7th, Darwin Airport managed to hit 36.3 °C which is very unusual. More over, it marked the hottest December day since 1976. On the night of the 6th, temperatures struggled to dip below 30 °C just reaching 29.1 °C in the early hours of the 7th. This was the hottest night for any month in 3 years.

  • Darwin endures a hot "build up" weather
  • Top End sees very much below average rainfall
  • Alice Springs District sees above average maximum and minimum temperatures
Map of decile rank of rainfall Map of Decile rank of mean maximum temperature Map of Decile rank of mean minimum temperature
Rainfall rank Maximum temperature rank Minimum temperature rank

Record lowest total annual rainfall
Total rainfall
for 2012 (mm)
Previous annual
driest
Years of
record
Annual
average
Warruwi 416.6 490.2 in 2002 82 1139.6



Record lowest temperature
Lowest temperature
in 2012 (°C)
Previous annual
coolest
Years of
record
Annual
average
Kulgera -4.8 on 7 Jul -4.7 on 15 Jul 1982 33 13.8




Summary statistics for 2012
Maximum temperatures
(°C)
Minimum temperatures
(°C)
Rainfall
(millimetres)
Mean
for
2012
Diff
from
average
Highest
for
2012
Mean
for
2012
Diff
from
average
Lowest
for
2012
Total
for
2012
Average
annual
total
Rank
of
2012
Fraction
of annual
average
Darwin-Daly (district 14GA)
Batchelor Aero 33.4 -0.3 38.6 4 Nov 20.3 -0.8 8.5 7 Jun 1540.8 1632.3 low 94%
Cape Don 31.9   36.9 7 Dec 25.2   19.4 22 Jul 911.0 1252.8 low 73%
Central Arnhem Plateau 32.1   39.9 6 Dec 19.8   8.8 13 Aug 1032.4
Darwin Airport 32.3 +0.3 36.6 13 Oct 22.5 -0.7 13.1 13 Aug 1724.5 1729.3 average 100%
Delamere Weapons Range 34.1 +0.4 42.3 13 Jan     9.5 11 Jun 511.6 878.5 low 58%
Dum In Mirrie AWS 31.8 +0.1 35.9 16 Apr 22.6 -0.7 12.6 23 Jul 1270.4 1788.6 v low 71%
Jabiru Airport 34.7 +0.4 40.5 31 Oct 22.4 -0.2 12.1 22 Jul 1356.4 1569.3 average 86%
Mango Farm 33.9 -0.2 40.0 24 Sep 19.4 -1.1 7.0 13 Aug 1618.9 1410.8 high 115%
McCluer Island 29.8   34.6 19 Dec 25.2   19.8 24 Jun 1022.8 1189.8 average 86%
Middle Point AWS 34.5 +0.4 39.5 27 Nov 19.6 -1.0 5.0 13 Aug 1345.0 1451.8 low 93%
Pirlangimpi 32.7 +0.5 36.8 23 Sep 22.1 -0.1 13.5 7 Jun 1672.6 2006.1 low 83%
Port Keats Aero 32.6 -0.4 37.3 11 Oct     10.6 21 Jun
Arnhem (district 14BC)
Cape Wessel 31.2   36.4 30 Dec 24.8   21.1 12 Aug 115.4 1211.3 v low 10%
Gove Airport 30.8 +0.2 36.1 20 Dec 22.0 -0.4 13.7 17 Aug 1001.6 1456.1 v low 69%
Groote Eylandt Airport AWS 31.8 -0.3 37.7 19 Dec 20.5 -0.2 8.4 13 Aug 783.0 1366.6 v low 57%
Ngayawili 31.5 +0.1 36.3 2 Dec 22.5 -0.3 12.9 6 Jun 967.0 1533.9 v low 63%
North East Island 30.3   35.8 13 Jan 24.6   18.6 16 Aug 507.4 844.0 low 60%
Roper-Mcarthur (district 14DE)
Centre Island 31.0 -0.2 39.1 6 Dec 23.3 -0.5 14.7 4 Jul 839.4 1037.8 average 81%
McArthur River Mine 34.5 0.0 44.1 6 Dec 19.0 -0.6 3.2 5 Jul 693.1 752.1 average 92%
Wollogorang     42.0 6 Dec 17.8 -1.1 3.3 13 Aug 814.1 960.1 average 85%
Victoria (district 14F)
Timber Creek 35.0 +0.1 43.0 7 Dec 20.1 -1.0 5.5 22 Jun
Victoria River Downs 34.4 0.0 43.8 7 Dec 17.9 -1.7 2.0 3 Jul 731.3 648.9 average 113%
Barkly (district 15A)
Tennant Creek Airport 31.7 -0.1 43.2 5 Feb 19.1 -0.7 6.7 21 Jun 491.2 474.7 average 103%
Alice Springs (district 15B)
Alice Springs Airport 29.6 +0.9 43.2 24 Dec 11.9 -1.3 -5.2 7 Jul 209.4 283.7 average 74%
Arltunga 28.4 -0.1 41.2 24 Dec 12.3 -1.0 -4.7 2 Aug 276.4 298.2 average 93%
Curtin Springs 29.9 +0.3 44.4 23 Dec 12.9 -0.5 -3.0 10 Jul 247.0 239.4 average 103%
Jervois 30.7 -0.2 43.6 30 Jan 14.7 +0.1 -1.5 2 Aug 179.4 295.7 low 61%
Rabbit Flat 33.8 +0.2 44.8 8 Dec 15.8 -0.8 -2.0 5 Jul 263.9 485.5 low 54%
Territory Grape Farm 30.5 -0.2 42.4 8 Dec 13.8 -0.7 -1.2 1 Aug 253.4 322.7 average 79%
Walungurru 32.7   45.3 24 Dec 18.6   3.1 10 Jul 146.0
Yulara Aero 30.0 +0.1 44.1 25 Nov 12.9 -1.1 -2.2 16 Jul 212.6 288.3 average 74%

Notes

A Climate Summary is prepared to list the main features of the weather in Northern Territory using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 11 am on Thursday 13 December 2012. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages are long-term means based on observations from all available years of record, which vary widely from site to site. They are not shown for sites with less than 10 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site, based on the decile ranking (very low rainfall is in decile 1, low in decile 2 or 3, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.

Further information

Media
(03) 9669 4057
Enquiries