DULLEST AUGUST AT ARMAGH FOR 13 YEARS, WARMER AND SLIGHTLY WETTER THAN

AVERAGE.  WARMEST SUMMER AT ARMAGH FOR 15 YEARS, DRIEST FOR EIGHT YEARS

AND SLIGHTLY DULLER THAN AVERAGE

 

 

Armagh Observatory, 6th September 2021:  Armagh Observatory reports that

August 2021 was the dullest August at Armagh for 13 years.  Although

warmer and slightly wetter than average, it was also the driest August

at Armagh for three years. Taking the three months June, July, and

August together, the meteorological summer was the warmest at Armagh for

15 years, the driest for eight years and slightly duller than average.

 

With 100.7 hours of recorded strong sunshine this August was the dullest

at Armagh for 13 years, that is, since the exceptionally dull August

2008 (69.0 hours of strong sunshine). This is approximately 76% of the

140-year long-term (1881-2020) average number of hours of strong

sunshine at Armagh (132.7 hours) and nearly 72% of the most recent

(1991-2020) 30-year average (140.6 hours).

 

The sunniest days were 11.5 hours on the 28th, 11.4 hours on the 25th

and 9.8 hours on the 24th.  Only four other days recorded more than 6

hours of strong sunshine.

 

The mean monthly temperature was nearly 15.9 degrees Celsius (60.6

Fahrenheit), almost 1.3 C warmer than the 225-year long-term (1796-2020)

average August temperature at Armagh (14.63 C) and 0.4 C warmer than the

most recent (1991-2020) 30-year August average (15.48 C).

 

Average August temperatures at Armagh have increased markedly over the

last 30 years or so.  For example, the (1981-2010) 30-year average was

15.38 C and the (1961-1990) 30-year average was 14.82 C.

 

The warmest day (highest maximum air temperature) was 25.4 C on the

25th, followed by 24.2 C on the 24th and 23.3 C on the 4th.  The coldest

day (lowest maximum air temperature) was 16.1 C on the 16th, followed by

16.4 C on the 17th.

 

The warmest night (highest minimum air temperature) was 14.7 C on the

11th followed by 14.2 C on the 8th.  The coldest night (lowest minimum

air temperature) was 6.7 C on the 2nd, followed by 8.4 C on the 28th.

There was only one ground frost this month, which was -0.3 C on the 2nd.

 

The observer reported an unusually large flight of approximately 50

feeding swallows above the weather station on the morning of the 15th,

and on the 18th two ravens harrying a buzzard.

 

Total August precipitation was 90.00 mm (3.54 inches) including six

trace values, that is, 89.7 mm if trace values are ignored.  This is

9.3% more than the 183-year long-term (1838-2020) average August

precipitation at Armagh (82.35 mm) and 14.5% more than the most recent

(1991-2020) 30-year August average (78.62 mm). Owing to a very wet spell

between the 5th and the 7th, this August was slightly wetter than

average, but it was still the driest August at Armagh for three years,

that is, since August 2018 (78.85 mm).

 

The wettest day was 20.6 mm (0.81 inches) on the 6th.  This was preceded

by 19.7 mm on the 5th and followed by 15.1 mm on the 7th. These three

days provided nearly 62% of the whole month’s precipitation.  The only

other day with significant rainfall was the 21st, with 11.3 mm.

Thunder was heard during the early afternoon of the 9th.

 

Apart from a few days beginning on the 5th of August, the month was

dominated by high atmospheric pressure.  This culminated on the 31st in

what was an exceptionally high atmospheric pressure for August,

approximately 1035 mbar (reduced to mean sea level).  This was equal or

close to several other nearly equal extreme August atmospheric pressures

in the Observatory’s calibrated 170-year record of daily pressure

readings extending back to 1850.

 

The three months June, July, and August together comprise the

meteorological summer.  This summer was the warmest at Armagh for 15

years, the driest for eight years and slightly duller than average.

 

The mean summer temperature was 16.19 C, which is approximately 1.87 C

warmer than the 225-year long-term (1796-2020) average summer

temperature at Armagh (14.32 C) and approximately 1.10 C warmer than the

most recent (1991-2020) 30-year summer average (15.10 C).  This was the

warmest summer at Armagh for 15 years, that is, since summer 2006 (16.30

C), and only slightly cooler than the summer of 1983 (mean temperature

16.23 C).  In round figures the warmest summers at Armagh are now 1995

(16.5 C); 2006 (16.3 C); 1983, 2021, 2018, 1826 and 2013 (all

approximately 16.2 C); 1976 (16.1 C); and 1846 (16.0 C).

 

Total summer precipitation was 157.85 mm (6.21 inches) including 11

trace values, that is, 157.30 mm if trace values are ignored.  This is

only 72% of the 183-year long-term (1838-2020) average summer

precipitation at Armagh (219.44 mm) and 75% of the most recent

(1991-2020) 30-year average (210.55 mm).  This was the driest summer at

Armagh for eight years, that is, since summer 2013 (146.25 mm).

 

There were 413.0 hours of strong sunshine during summer 2021, which is

approximately 97% of the 140-year long-term (1881-2020) summer average

(427.0 hours) and 98% of the most recent (1991-2020) 30-year average

(420.0 hours).  Summer 2021 was much sunnier than the very dull summer

of 2020 (294.1 hours), but slightly less sunny than the summers of 2019

(435.2 hours) and 2018 (478.2 hours).

 

FOR FURTHER INFORMATION PLEASE CONTACT: Mark Bailey at the Armagh

Observatory, College Hill, Armagh, BT61 9DG.  Tel.: 028-3752-2928; FAX:

028-3752-7174; mark.bailey@armagh.ac.uk; URL:

http://climate.armagh.ac.uk/.

 

These data refer to observations at Armagh Observatory, which has

been recording the weather at Armagh since 1795.

 

For further information, please contact:

 

Professor Mark E. Bailey

Emeritus Director of Armagh Observatory

Armagh Observatory and Planetarium

College Hill

Armagh

BT61 9DG

 

Tel: 028-3752-2928

E-mail: mark.bailey@armagh.ac.uk

 


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