Armagh Observatory reports that October 2022 was much wetter and warmer than average and with roughly average sunshine. This was the wettest October at Armagh for 11 years and probably the fourth-wettest October at Armagh since daily rainfall records began in 1838.
Total measured precipitation was 149.45 mm (5.88 inches) including one trace value, that
is, 149.4 mmm if trace values are ignored. This is nearly 86% more than the 183-year
long-term (1838–2020) average October precipitation at Armagh (80.4 mm) and 85% more
than the most recent (1991–2020) 30-year average (81.0 mm). Three of the five wettest
Octobers at Armagh since 1838, namely October 1870 (193.75 mm), October 2011 (182.75
mm), October 2002 (158.10 mm), October 1865 (150.0 mm) and October 2022 (149.45
mm), have occurred in the last 20 years.
Owing to a slight spillage amounting to an estimated 2 mm of collected rainfall for the 16th
that was lost before it could be measured the total precipitation for the month is probably
closer to 151 mm. This would make October 2022 slightly wetter than October 1865, and
therefore the fourth-wettest October on record at Armagh.
The wettest day was the 16th with a measured total rainfall of 23.7 mm but owing to spillage
was slightly more than this. The next wettest day was the 21st with 22.5 mm, followed by
the 19th and the 31st (Halloween) both with 16.3 mm. Other than one trace value on the
17th only one day of the month (the 8th) had no measurable rainfall.
Two ravens were seen swirling and diving on the 26th, and separate double rainbows were
recorded on the afternoon of the 7th and another on the afternoon of the 30th. The
predicted partial solar eclipse was recorded through fast-moving patchy clouds on the
morning of the 25th. Despite the high total rainfall during the month and occasional strong
winds particularly on the 17th and 18th this was a relatively calm month with no named
autumn storms affecting Northern Ireland.
With an average temperature of almost 12.0 Celsius (53.4 Fahrenheit) this was a very mild
October, only 0.1 C cooler than the very warm October 2021 and the ninth-warmest
October at Armagh since daily measurements of temperature began in 1795. This October
was 2.42 C warmer than the 183-year long-term (1796–2020) average October
temperature at Armagh (9.48 C) and 1.66 C warmer than the most recent (1991–2020) 30-
year average (10.37 C).
Although 30-year average temperatures at Armagh have increased significantly during the
last 40 years, those for October have registered the least increase among the twelve
calendar months. While the (1961–1990) October 30-year average at Armagh was 10.11
C, the corresponding most recent (1991–2020) average is just 10.37 C, corresponding to
an average temperature increase at Armagh of only 0.25 C between these two baselines
30 years apart.
The warmest day (highest maximum air temperature) was 18.0 C, a value attained on the
afternoons of both the 20th and 27th, followed by 17.4 C on the 1st. The lowest maximum
air temperature, notionally the coolest day, was 11.6 C on the afternoon of the 15th,
followed by 11.7 C conventionally attributed to the 16th although very unusually the actual
maximum occurred in the small hours of the 17th. The third-lowest maximum air
temperature this month was 13.2 C and attributed to the 19th, although the actual maximum
had occurred a few minutes before the normal time of observations at 09:00 GMT on the
These seeming inconsistencies highlight the role played by improvements in
instrumentation. In the past, observers had little or no detailed knowledge of when a day’s
highest or lowest air temperature had occurred. As a result, the maximum air temperature
was conventionally attributed to the previous day, that is, to the 15-hour period between
09:00 and midnight GMT, and the minimum to the day on which the measurement was
taken, that is, to the following 9-hour period between midnight and 09:00 GMT. Nowadays,
many digital thermometers supply the times of maximum and minimum temperatures,
giving greater insight into our changing weather. However, for consistency with earlier
records the date of the temperature maximum is still conventionally “thrown back” to the
previous day, that is, to the period between 09:00 and midnight GMT, while the date of the
minimum is conventionally taken to be the same as when the observations are recorded,
that is, to the period between midnight and 09:00 GMT.
These issues are rarely important but can sometimes cause confusion and the weather
this October supplies an example. This month, the highest minimum air temperature
(notionally, the warmest night) was recorded as 12.3 C at 09:00 GMT on the 4th, and so
conventionally attributed to the 4th. In fact, this highest minimum temperature had occurred
close to the time of observations the previous day. The second-highest minimum
temperature, namely 11.7 C, was coincidentally recorded at 09:00 GMT on three separate
days, namely the 3rd, 22nd and 23rd, and conventionally attributed to those days.
However, while the minimum on the 22nd had indeed occurred sometime after midnight
and before 09:00 GMT that day, the minima on the 3rd and 23rd had in fact occurred close
to or shortly after 09:00 GMT on the previous day, that is, on the 2nd and 22nd respectively.
The lowest minimum air temperature (notionally, the coldest night) was 2.1 C during the
early morning of the 18th, followed by 4.1 C in the small hours of the 13th and 4.2 C on
the 19th, although in this latter case the temperature minimum had occurred close to the
time (09:00 GMT) of observations the previous day.
There were five ground frosts (minimum grass temperatures less than or equal to zero
Celsius) this month, of which the three coolest were -3.1 C on the 18th, -2.5 C on the 13th
and -1.4 C on the 10th. With a lowest minimum air temperature of 2.1 C there were no air
frosts this month.
Halloween (31st October) was mild and very wet, with a mean temperature of 12.7 C and
a maximum of 14.7 C and a rainfall total amounting to 16.3 mm (shared with the 19th).
This was the warmest Halloween at Armagh for seven years, that is, since Halloween 2015
with a mean temperature of 13.4 C and a maximum of 15.8 C.
This October, with 91.0 hours of strong sunshine, had roughly average sunshine,
approximately 4% more than the 140-year (1881–2020) long-term October average at
Armagh (87.2 hours) and 1% less than the most recent (1991–2020) 30-year average (92.0
hours). The sunniest day was the 18th with 8.4 hours of strong sunshine, followed by the
7th with 8.2 hours and the 14th with 7.3 hours.
These data refer to observations at Armagh Observatory, which has been recording
the weather at Armagh since 1795.
FOR FURTHER INFORMATION PLEASE CONTACT:
Mark Bailey at the Armagh Observatory,