May 2020:
May 2020 was the 2nd driest in 140 years of
continuous records for the city. The direst was 1905 when only 4.3 mm was
recorded. The rainfall duration for the whole month was only 4 hours and
there was a 17 and 10 day consecutive period when no measurable rain fell.
From the 2nd of May until the month end there was only 0.8 mm of rain.
It was the sunniest May on record, the data started in 1995. In 2020 there
was a record 74.2% of the maximum sunshine which is also the highest
of any month at this site since 1995. The previous sunniest month was July
2006 when 71.6% of the maximum sunshine was recorded.
The average of the sun’s energy of 23.03 Langley’s in May was also the
highest of any month since this data started.
The average temperature on 14.8°C in May 2020 was 1.5°C above the 30 year
average for the month. However the average maximum temperature of 20.1°C was
the 3rd highest for May in Bristol since the data started in 1938.
The average air pressure of 1020 mb was the equal 3rd highest since this
data started in 1994..
Spring 2020 It
was the equal 3rd warmest, with 1998, since data began in 1891. The average
temperature was 11.8°C in 2020 whilst the 30 year
average spring is 10.3°C. With regard to the average maximum spring
temperature it was the equal warmest (with 2003) on record from 115 years of
data. The 30 year average is 14.1°C in 2020 it was 16.7°C.
It was the sunniest spring on record with 61% of the maximum for March,
April and May. This data started from 1996. It was the 4th sunniest March
and the sunniest April and May with regard to the percentage of maximum
sunshine.
It was the 19th driest spring in 139 years of data and was only 66% of the
30 year average.
Annual 2019: In 129 complete
years of Bristol's average temperatures in 2019 it was the joint 5th warmest
with (with 1999, 2002, 2003 & 2015)
with an average temperature of 11.9°C.
The annual rainfall of 984.6 mm for 2019 was 106% of the 30 year average for
the city of 889.9 mm. The first 7 months, January to July,
had a below average rainfall of 83%, whilst the last 5 months, August to
December, had 139% of the 30 year average.
In 2019 49% of all
the wind directions were from the SW or WSW. Annual average pressure of 1014
mb was lowest since 1012 mb in 2014.
2019 was the sunniest complete year of data, with regard to Wm2, since this
parameter started in 2006. In terms of percentage of maximum sunshine it was
the 5th sunniest at 40.7%, since 2010 when 41.2% was recorded.
The
2019 Annual summary is here:
http://www.bristolweather.org/weather2019annual.htm
For the full monthly summary please go here:
http://www.bristolweather.org/weather2020May.htm
The
Meteorological site is situated in an urban housing area approximately one
mile to the south of the Centre of Bristol.
This area is in a district called Totterdown.
Statistical correlations with the Bristol
Meteorological Office site, that was
less than two miles to the North and was
situated on top of a City Centre office block, were generally good with
rainfall and barometric data particularly close.
The site of the station is approximately 34 metres above sea level with the
manual instruments mounted in a Stevenson screen. The screen is sited
centrally in a small concreted garden area. A Snowdon
rain gauge is mounted correctly in the ground but does not have the full open
space required around it. A Davis
Vantage Pro2 Plus automatic weather station (AWS) was
added in May 2005 and this is mounted 4 feet above a concrete shelter. The
wind data is gathered automatically from a Davis Vantage Pro2 Plus anemometer which is
sited 3.3 metres (10 feet) above the house top.
Manual observations are still taken at approximately 09:00 hours GMT every
day for rainfall and cloud cover. Rainfall manually recorded in the Snowdon rain gauge is entered for the previous day. The
wind data is constantly logged and automatically reset at 24:00 hours GMT
every day (in the summer BST -1 hour. The Davis rainfall tipping bucket was recalibrated in November 2005 and is now
consistently under 3% under recording (an improvement from installation in
May 2005 when 10% was more
typically the norm).
Since the arrival of the Davis
Vantage Pro2 Plus equipment in May 2005 temperatures, humidity and barometric
pressure are recorded from the new equipment. These figures will be more
accurate and will be taken at exactly 09:00 GMT (in the summer BST -1 hour)
as the data is now logged to a computer.
By default the Davis
equipment records every parameter for the 24 hour period 00:00 to 23:59 BST
or GMT. Data analysis will enable manual data extraction of temperatures and
rainfall to 09:00 GMT (adjusted in the summer). Due to the 0.2 mm (tipping
bucket) measurements of precipitation recorded by the Davis equipment the
Snowdon rain gauge will still be used due to its greater accuracy (see
above).