Met Office: A review of the UK’s climate in 2021

The 2021 UK average temperature is an example of a circumstance that was previously rather uncommon and uncommon, however is now commonplace. Thanks to environment “attribution” science, we can quantify the function of human-caused climate modification on these statistics using now well-established attribution methods..

Moving standards.

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It is very important to keep in mind the effect that the brand-new reference period has on these figures. The UKs nationwide temperature level observations cover more than 100 years. The climate of the UK has actually warmed by near to 1C since the late 20th century, so it comes as little surprise that a relatively “average” year by todays standards is significantly warm if we compare it to the longer historical record..

The all-forcings scenario encompasses 2100 based on the emissions scenario SSP2-4.5– a “middle-of-the-road” narrative for future human-caused emissions– to suggest the UKs possible future environment.

In this review, we unpack the UKs environment in 2021– for the year as an entire and each specific season. Our analysis also reveals that the possibility of seeing a year as warm as 2021 in a world without environment modification is just 2.5%– however might be as likely as 89% by the end of the century.

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The maps listed below program typical temperature level (left), rains (middle) and sunshine duration (right) compared to 1991-2020, across the UK in 2015. Rain was slightly below par total– particularly for north and west Scotland– and sunlight was slightly above average in the north and west and below in the southeast of the UK..

Maps and charts refer to temperature level for private months of the year. The colour of the shading suggests months above average in red, and below average in blue.

These define “reference” climatological durations as being the most recent 30-year duration beginning with a year ending in “1”. The existing reference climate period has, therefore, recently been upgraded to 1991-2020, replacing the previous referral period of 1981-2010. For long-term climate tracking, 1961-1990 is also retained as a standard.

Chart revealing mean (dark blue line), maximum (red) and minimum (light blue) day-to-day temperature levels for the spring of 2021. The 1991-2020 typical everyday temperature level is revealed by the black line, with the range shown by the grey lines. Credit: Met Office.

Maps of temperature level anomalies (C, left), rainfall (% of average, middle) and sunshine (% of average, right) abnormalities relative to a 1991-2020 average. Looking at the annual average temperature level masks a lot of interesting weather within the year. The figure below shows UK day-to-day typical temperature levels for the year. The colour of the shading indicates months above average in red, and listed below average in blue. The colour of the shading shows months above average in red, and listed below average in blue.

After this quick warm interlude, snowy and cold conditions returned rather suddenly with UK average temperature levels stopping by almost 10C (pdf) from near-record highs to near-record lows in just a week. The precipitous drop in temperatures from late March into early April can be seen in the dark blue line in the chart below.

“average” in todays environment is still the UKs 18th hottest in a record extending back to 1884.

From these simulations, the likelihood of experiencing a year warmer than 2021 is 2.5% for a natural environment without human emissions of greenhouse gases, 66% for the present day climate (2011-30) and 89% for a possible future (2081-2100) climate scenario.

On the other hand, May was extremely wet– the 4th wettest on record for the UK and wettest on record for Wales. Extremely couple of days in April or May were warmer than average and the spring overall was the coldest considering that 2013.

Despite the record-breaking turn of the year, a look back at 2021 exposes a relatively average year for the UKs weather– specifically compared to the memorable and remarkable conditions of 2020..

The year 2021 is 0.97 C warmer than the 1961-90 average, and against this baseline nearly 65% of days in the year would be warm (red shading) and just 35% cooler (blue shading) than average. This compares to 51% and 49%, respectively, for 1991-2020.

Nevertheless, the odds are very clearly moving, such that 2021 temperature levels are amongst the hottest relative to our pre-21st century climate, are close to typical for today day and will likely be reasonably cool in the future.

Taking a look at each season particularly, 2021 started on a relatively cold theme. It was total the coldest January given that 2010, and the coldest for any calendar month since the snowy and cold March of 2013.

The cold style continued into February with a temperature level of -23.0 C taped at Braemar on 11 February. This was the most affordable temperature taped in the UK given that 1995..

As the chart listed below programs, experiencing temperatures listed below -20 C (dark blue bars) is not overly common. In between 1961 and 1990 it occurred in 14 of 30 winters, but in the duration 1991-2020 it took place in simply 3 years. Seeing temperatures below -15 C (light blue bars) has likewise become much less frequent in recent years, with 2010 a notable exception.

Last year was the 18th warmest year in a series dating back to 1884– and 13 of the 17 warmer years have all been in the 21st century (with an additional three in the 1990s, and just 1949 any earlier than that)..

Looking at the yearly average temperature level masks a lot of fascinating weather within the year. The figure below programs UK daily typical temperature levels for the year. In general, there is a fairly even split of days above (red shading) and below (blue shading) the 1991-2020 climatological average.

Maps of temperature anomalies (C, left), rainfall (% of average, middle) and sunlight (% of average, right) anomalies relative to a 1991-2020 average. The darker shading shows the greater departure from average. Credit: Met Office.

The meteorological winter (December 2020 to February 2021) was 0.6 C chillier than the 1991-2020 average, with 119 % of average rainfall and 95% of average sunshine. This is a “cold” winter in our existing climate, however not as extreme as cold winter seasons of the past.

Overall, Northern Ireland experienced its third-hottest summer on record, Scotland its 4th, and for the UK as a whole it was the ninth hottest. For Glasgow, ahead of the COP26 environment top that would be kept in November, it was the most popular summer season on record in a series returning to 1884.

The record breaking warmth over the #NewYear 2022 is thanks to a circulation of warm subtropical air from the Azores But the weather condition is set to briefly turn wintry this week with cold winds stemming from the Arctic resulting in overnight frosts, and snow for some by Tuesday ❄ pic.twitter.com/Vr9yvtOAvy— Met Office (@metoffice) January 1, 2022.

On 17 July, Ballywatticock in County Down recorded a temperature of 31.2 C, which broke the Northern Ireland temperature level record and is the first time a temperature in excess of 31C has actually been recorded in the area. Temperatures above 30C are rare, having taken place in just 8 of the last 60 years. This record did not last for extremely long though with Castlederg in County Tyrone tape-recording 31.3 C a few days later on the 21 July.

Early summer was relatively uneventful for UK weather condition, although parts of southeast England received as much as two times their average rainfall for June..

Attribution.

October was also warm, however a significant wet spell late in the month saw some fairly exceptional rainfall totals, going beyond 400mm over parts of the Cumbrian fells in the last 6 days of the month. This was a result of a “warm conveyor” (pdf)– a circumstance associated with an “atmospheric river” bringing moisture-laden air from the subtropics– and shared some resemblances with severe rains occasions of December 2015 and November 2009 (pdf).

Number of days each year in which a minimum of one station in the UK meteorological observing network tape-recorded temperatures listed below -15 C in light blue, or -20 C in dark blue for all years from 1960 to 2021. Information from the Met Office; graphic produced by Neil Kaye.

An optimum temperature level of 24.5 C was recorded at Kew Gardens on 30 March, which is only the 3rd day on record with a UK March temperature level surpassing 24C. A day-to-day minimum of 12.7 C at Kinloss in Moray that day was also Scotlands equal highest March everyday minimum.

As the final month of the year– and the first month of the new winter season, December was rather cloudy and mild. The year concluded with the greatest New Years Eve temperature on record for the UK– provisionally 16.5 C at Bala in north Wales, but this might be changed by 16.8 C at Colwyn Bay as soon as verified. However, these temperature levels did not threaten the all-time December UK extreme (18.7 C tape-recorded at Achfary, Sutherland on 28 December 2019). The warm spell likewise indicated a provisional record-breaking high temperature level for New Years Day to see in 2022– 16.3 C at St James Park in London, which beats the previous record of 15.6 C at Bude in Cornwall in 1916.

The southeast of England saw rains in parts reaching 150% to 200% of the summertime average– in contrast to the majority of the remainder of the UK, which had a drier than average summer season. This was reflected in sunlight statistics too, with northwestern locations tape-recording a sunnier than typical summer season and main and southeast England taping below par.

After its cold start, April proceeded to be the frostiest and sunniest April on record for the UK.

Storm Evert at the end of July was the first called storm to take place in July, bringing unseasonably strong winds to southern and southwest England with a peak of 77mph at Needles, Isle of Wight. July is climatologically the calmest month of the year, but we do periodically experience such weather systems at this time of year..

Summer.

Air pressure was anomalously high to the north of the UK– a pattern resulting in calm conditions for numerous parts of Europe and marginally the warmest summer on record for the continent.

Chart showing UK summertime (June-July-August) typical wind speed from 1969 to 2021 (dark blue line). Other lines suggest the 1991-2020 average (pink), the 2021 low (brown), the long-term high (red dotted) and long-term pattern (black dotted). Credit: Met Office.

Regardless of storm Evert, the summer overall was significantly calm, with the lowest UK summertime typical wind speed in a Met Office series considering that 1969. This is indicated in the chart below, which shows the typical summer wind speed each year (dark blue line), with the record low of 2021 highlighted by the brown line.

The UK indicate temperature for 2021 was 9.28 C. This is a simple 0.12 C above the 1991-2020 recommendation duration, making it an extremely “average” year in contrast to the environment of the current past..

More analysis and statistics for 2021 will be published in the Met Office annual State of the UK Climate report in July 2022.

It works to reflect even more on these figures. Human-caused environment modification does not mean a continuous year-on-year increase in UK temperature level, because our regional climate is still greatly influenced by natural irregularity. So, even by the end of the century, we can still expect to experience some years cooler than 2021..

Storm Christoph (pdf) saw some exceptional rains overalls throughout 18-20 January, requiring evacuation of homes in parts of Warrington, Chester and Manchester– complicated by the coronavirus pandemic and snow. The 18-20 January duration was provisionally the wettest three-day duration on record for the northwest England and north Wales area in a series from 1891.

Storm Arwen affected the UK on 26 and 27 November and was accompanied by an unusual “red” serious weather caution from the Met Office for wind along the northeast coast of England and Scotland. This was a particularly harmful wind storm and the northerly direction of the winds– rather than the prevailing (south)- westerlies– would have been a contributing element, with cold and snow further making complex some of the healing. Snow was recorded as falling as far south as Dorset and over greater ground in northern England there were some considerable accumulations.

Spring.

Winter.

It was the 2nd warmest September on record for the UK, and for Northern Ireland its warmest– with temperatures approaching 2C above the 1991-2020 average. With an average temperature level of 14.7 C for the UK, September of 2021 was in truth only a little cooler than an “typical” August (15.1 C).

Right up till the 1990s, a year as warm as 2021 would have been considered rather severe. This is highlighted in the figure listed below, which reveals the exact same daily average chart as above however with a 1961-90 recommendation duration, instead of 1991-2020.

Fall.

We have actually carried out analysis using a collection of climate designs from the 6th Coupled Model Intercomparison Project (CMIP6). This supplies a set of 83 simulations with “all environment forcings” consisted of and 71 with “natural-only forcings”– that is, without the influence of human-caused greenhouse gas emissions consisted of– from 14 contributing models..

Was 2021 a typical year for UK climate? The answer rather depends upon what we define as “average”– a rather difficult principle in a moving climate..

Charts and maps refer to temperature level for private months of the year. The colour of the shading indicates months above average in red, and listed below average in blue.

Overall, it was the warmest autumn on record for Northern Ireland and 3rd warmest for the UK (behind 2006 and 2011). The attribution approach described previously has actually also been applied to the autumn statistics. This suggests that UK autumn typical temperature levels at or above 2021 would be approximately a 1-in-500 year event in a natural climate (with an uncertainty range of 395 to 771 years), which has actually become a 1-in-4 year occasion for the present-day environment (uncertainty variety of 4.0 to 4.6)..

The use of several climatological references, our long tradition of climate observations and state-of-the-art environment modelling permits us to place todays weather condition and environment into past, future and present context whether an event is extreme or, as in this case, rather more typical.

As 2021 came to a close with a record New Years Eve high temperature level for the UK, 2022 began in a similar fashion with its own record high for New Years Day.

Throughout mid-July there was a more significant heatwave and the Met Office issued its first-ever amber severe heat warning for western parts of the UK..

All national meteorological agencies, consisting of the Met Office in the UK, retain comprehensive historic records of weather and climate observations. In order to facilitate international consistency in the method these stats are reported, the World Meteorological Organization provides guidance on climatological finest practice (pdf)..

Fall was constantly warmer than average, with a temperature of 30.8 C taped at Hartpury College in Gloucestershire on the 7 September..

While this fall is fairly extreme compared to the historical climate, it is expected to end up being significantly most likely to go beyond these temperatures in the future.