The highest average temperature recorded in 2024 until November was in August, at 16.8 degrees Celsius. Since 2015, the highest average daily temperature in the UK was registered in July 2018, at 18.7 degrees Celsius. The summer of 2018 was the joint hottest since institutions began recording temperatures in 1910. One noticeable anomaly during this period was in December 2015, when the average daily temperature reached 9.5 degrees Celsius. This month also experienced the highest monthly rainfall in the UK since before 2014, with England, Wales, and Scotland suffering widespread flooding. Daily hours of sunshine Unsurprisingly, the heat wave that spread across the British Isles in 2018 was the result of particularly sunny weather. July 2018 saw an average of 8.7 daily sun hours in the United Kingdom. This was more hours of sun than was recorded in July 2024, which only saw 5.8 hours of sun. Temperatures are on the rise Since the 1960s, there has been an increase in regional temperatures across the UK. Between 1961 and 1990, temperatures in England averaged nine degrees Celsius, and from 2013 to 2022, average temperatures in the country had increased to 10.3 degrees Celsius. Due to its relatively southern location, England continues to rank as the warmest country in the UK.

England's highest monthly mean air temperatures are typically recorded in July and August of each year. Since 2015, the warmest mean temperature was measured in July 2018 at 18.8 degrees Celsius. On the other hand, February of that same year registered the coolest temperature, at 2.6 degrees Celsius. In April 2025, the mean air temperature was 10.3 degrees Celsius, slightly higher than the same month the previous year. The English weather England is the warmest region in the United Kingdom and the driest. In 2024, the average annual temperature in England amounted to 10.73 degrees Celsius – around 1.1 degrees above the national mean. That same year, precipitation in England stood at about 1,020 millimeters. By contrast, Scotland – the wettest region in the UK – recorded over 1,500 millimeters of rainfall in 2024. Temperatures on the rise Throughout the last decades, the average temperature in the United Kingdom has seen an upward trend, reaching a record high in 2022. Global temperatures have experienced a similar pattern over the same period. This gradual increase in the Earth's average temperature is primarily due to various human activities, such as burning fossil fuels and deforestation, which lead to the emission of greenhouse gases. This phenomenon has severe consequences, including more frequent and intense weather events, rising sea levels, and adverse effects on human health and the environment.

The average temperature across the United Kingdom presented a trend of continuous growth since 1961. During the first period, from 1961 to 1990, the country recorded an average temperature of *** degrees Celsius. In the next period, from 1991 to 2020, the UK's average temperature increased by *** degrees Celsius and increased further by *** degrees Celsius between 2014 and 2023. In the latter year, figures remained at ** degrees Celsius, *** degrees warmer than the average recorded between 1961 and 1990, illustrating the effects of climate change. Nevertheless, 2022 was the warmest year in the United Kingdom.

The annual mean temperature in the United Kingdom has fluctuated greatly since 1990. Temperatures during this period were at their highest in 2022, surpassing ** degrees Celsius. In 2010, the mean annual temperature stood at **** degrees, the lowest recorded during this time. Daily temperatures Average daily temperatures have remained stable since the turn of the century, rarely dropping below ** degrees Celsius. In 2010, they dropped to a low of **** degrees Celsius. The peak average daily temperature was recorded in 2022 when it reached **** degrees. This was an increase of *** degree Celsius compared to the long-term mean, and the most positive deviation during the period of consideration. Highs and lows The maximum average temperature recorded across the UK since 2015 was in July 2018. This month saw a maximum temperature of **** degrees Celsius. In comparison, the lowest monthly minimum temperature was in February of the same year, at just minus *** degrees. This was an especially cold February, as the previous year the minimum temperature for this month was *** degrees.

For an urban heat island map during an average summer see this dataset. A heatwave refers to a prolonged period of unusually hot weather. While there is no standard definition of a heatwave in England, the Met Office uses the World Meteorological Organization definition of a heatwave, which is "when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5°C, the normal period being 1961-1990". They are common in the northern and southern hemisphere during summer have historically been associated with health problems and an increase in mortality. The urban heat island (UHI) is the phenomenon where temperatures are relatively higher in cities compared to surrounding rural areas due to, for example, the urban surfaces and anthropogenic heat sources. This urban heat island map was produced using LondUM, a specific set-up of the Met Office Unified Model version 6.1 for London. It uses the Met Office Reading Surface Exchange Scheme (MORUSES), as well as urban morphology data derived from Virtual London. The model was run from May until September 2006 and December 2006. This map shows average surface temperatures over the summer period of 2006 at a 1km by 1km resolution. To find out more about LondUM, see the University of Reading’s website. The hourly outputs from LondUM have been aggregated and mapped by Jonathon Taylor, UCL Institute for Environmental Design and Engineering. Variables include: WSAVGMAX= the average of the maximum daily temperatures across the summer period (May 26th-August 31st) WSAVG=the average temperature across the summer period WSAVGMIN = the average minimum daily temperature across the summer period HWAVGMAX= the average of the maximum daily temperatures across the 2006 heatwave (July 16th-19th) HWAVG=the average temperature across the across the 2006 heatwave HWAVGMIN = the average minimum daily temperature across 2006 heatwave period The maps are also available as one combined PDF. The gif below maps the temperatures across London during the four-day period of 16-19th July, which was considered a heatwave. If you make use of the LondUM data, please use the following citation to acknowledge the data and reference the publication below for model description: LondUM (2011). Model data generated by Sylvia I. Bohnenstengel (), Department of Meteorology, University of Reading and data retrieved from http://www.met.reading.ac.uk/~sws07sib/home/LondUM.html. () Now at Metoffice@Reading, Email: sylvia.bohnenstengel@metoffice.gov.uk Bohnenstengel SI, Evans S, Clark P and Belcher SeE (2011) Simulations of the London Urban Heat island. Quarterly journal of the Royal Meteorological Society, 137(659). pp. 1625-1640. ISSN 1477-870X doi 10.1002/qj.855. LondUM data (2013).

ERA-Interim is the latest European Centre for Medium-Range Weather Forecasts (ECMWF) global atmospheric reanalysis of the period 1979 to August 2019. This follows on from the ERA-15 and ERA-40 re-analysis projects. The dataset includes synoptic monthly mean analysed potential temperature level data on a reduced N256 Gaussian grid. Data are available at the 00, 06, 12 and 18 UT analysis times.

The wettest months in the United Kingdom tend to be at the start and end of the year. In the period of consideration, the greatest measurement of rainfall was nearly 217 millimeters, recorded in December 2015. The lowest level of rainfall was recorded in April 2021, at 20.6 millimeters. Rainy days The British Isles are known for their wet weather, and in 2024 there were approximately 164 rain days in the United Kingdom. A rainday is when more than one millimeter of rain falls within a day. Over the past 30 years, the greatest number of rain days was recorded in the year 2000. In that year, the average annual rainfall in the UK amounted to 1,242.1 millimeters. Climate change According to the Met Office, climate change in the United Kingdom has resulted in the weather getting warmer and wetter. In 2022, the annual average temperature in the country reached a new record high, surpassing 10 degrees Celsius for the first time. This represented an increase of nearly two degrees Celsius when compared to the annual average temperature recorded in 1910. In a recent survey conducted amongst UK residents, almost 80 percent of respondents had concerns about climate change.

This dataset contains temperature data (mean, min, max temperatures etc.) and topographic complexity data (rugosity, fractal dimension) obtained from thermal imaging and 3D model analysis of six panel designs of the 'Living Seawalls in Plymouth' installation in Plymouth, Devon (UK). Data were obtained by Franz Bauer (University of Plymouth) in August/September 2023 through in-situ thermal imaging in the intertidal zone (2-4 m above chart datum). The data were collected to understand the topographic properties that drive scale-dependent thermal patterns on different panel designs of an intertidal eco-engineering installation. These data were generated as part of the PhD project titled "Retrospective optimisation of multifunctionality on coastal urban infrastructure", funded by the Natural Environment Research Council ARIES Doctoral Training Partnership (grant number NE/S007334/1), University of Plymouth and Arup. For further information, please see the associated research paper: https://doi.org/10.1016/j.ecoleng.2025.107596.

Gridded hydrological model river flow estimates on a 1km grid over Great Britain for the period Dec 1980 - Nov 2080. The dataset includes monthly mean river flow, annual maxima of daily mean river flow (water years Oct - Sept), along with the date of occurrence, and annual minima of 7-day mean river flow (years spanning Dec-Nov), along with the date of occurrence (units: m3/s). The data are provided in gridded netCDF files. There is one file for each variable and ensemble member. To aid interpretation, two additional spatial datasets are provided: a) digitally-derived catchment areas and b) estimated locations of flow gauging stations both on the 1km x 1km grid. The data were produced as part of UK-SCAPE (UK Status, Change And Projections of the Environment; www.ceh.ac.uk/ukscape, Work Package 2: Case Study – Water) programme, a NERC-funded National Capability Science Single Centre award number NE/R016429/1.

A dataset of tropical and temperate butterflies.

Methods of data collection: Neotropical data were collected in Panama from February to June 2020 and from October 2021 to March 2022 during both wet (May to December) and dry (January to April) seasons (Supplementary Fig. 1, Supplementary Table 1) (Leigh, 1999). Temperate data were collected in the Czech Republic and Austria between April and August 2021 and in the UK between April and September 2009 and May and September 2018 (Supplementary Fig. 1, Supplementary Table 1) (Bladon et al., 2020). Data collection took place between 7:30 and 17:30. Neotropical field sites included lowland scrub and managed urban green spaces, secondary semi-deciduous lowland tropical forest, mountain rainforest and management agroforestry (Supplementary Table 1). Temperate field sites included calcareous meadows, grassland meadows, alpine/montane grassland, encroaching scrub, secondary forest, and exposed ground (Supplementary Table 1).

Butterfly body temperature and morphological measurements

Butterflies were captured with butterfly nets when encountered (without chasing) and data were collected following the protocol used by Bladon et al. (2020), as follows. Once in the net, and within 10 seconds, a temperature reading of the butterfly’s thorax (body temperature, Tb) was taken using a thermocouple (0.5 mm diameter) and handheld indicator (Tecpel Thermometer 305B, TC Direct, Uxbridge, UK). Air temperature (Ta) was taken at waist height where the butterfly was caught, with the thermocouple shaded from the sun. If the butterfly was resting on a substrate before capture, the temperature of the air 1 cm above where it was sat was recorded with the thermocouple (microclimate temperature, Tm). The butterfly was identified to species or subspecies. In the case of butterflies from the tropical Calephelis genus it was not possible to identify individuals to species, so data from these butterflies were aggregated to genus level. Forewing length (in mm) from the tip of the wing to the point where it meets the thorax was measured using callipers (at the Panama and UK sites only).

Description of each column: Species: species name Site: location of capture of the butterfly Date: date of capture of the butterfly Family: family the butterfly belongs to Activity: what the butterfly was doing when it was first encountered (nectaring, flying, resting, basking, interacting with other/same species). Tair.perch: if the butterfly was first encountered while on a perch, this is the temperature 1cm above the perch. All temperatures are in Celcius. Tbody: temperature of the thorax of the butterfly within 10 seconds of capture Tair: air temperature recorded at waist height in shade in the location the butterfly was first encountered Tperch: if the butterfly was first encountered while on a perch, this is the temperature of the surface of the perch Region: tropical (from Panama) or temperate (from Europe) Mean.winglength.mm: mean wing length of the species (one value per species) in mm Colour: the dominant wing colour of the butterfly Colour.value: the wing colour converted to a scale from 1 (white) to 6 (black) Sexual.dimorphism.in.colour: A Y (yes) or N (no) for whether that species has males and females having different dominant wing colours (so that their colour would be different between sexes) Migratory: A Y (yes) or N (no) for whether in the area of capture that butterfly species is known to be migratory Average.forewing.aspect.ratio: the average aspect ratio for the forewing of the butterfly (wing length divided by wing width) Subfamily: the subfamily the species belongs to Tribe: the tribe the species belongs to

Wind speed averages in the United Kingdom are generally highest in the first and fourth quarters of each calendar year – the winter months. Since 2010, the UK’s highest wind speed average was recorded in the first quarter of 2020, at 11.5 knots. During this period, 2010 was the only year that had the greatest wind speeds outside the winter months, with an average of 8.4 knots in the third quarter. In 2024, wind speeds ranged between a low of 7.9 knots in the third quarter and 9.4 knots in the first quarter. With few exceptions, UK wind speeds generally average at least eight knots annually. 2015 marked the year with the highest average wind speed in the UK (since the beginning of the reporting period in 2001), reaching an average of 9.4 knots. Wind power The UK has some of the best wind conditions in Europe for wind power. By 2023, there were 39 offshore wind farms operating across the UK, by far the most in Europe. Meanwhile, offshore wind power additions in the UK reached 1.14 gigawatts that same year. Quarterly rainfall Another weather phenomenon, UK rainfall also tends to be heaviest in the winter months. The average rainfall in the second quarter of 2024 was 254.5 millimeters, with figures in 2011 spiking to 738.6 millimeters. That year, precipitation levels in some parts of Scotland were the highest in one hundred years, while southern parts of England kept remarkably dry.

There were around 15 rainy days in the United Kingdom in July 2024. A rainday is when one millimeter or more of rain occurs in a day. The highest number of rain days was recorded in December 2015, at 22.2 The fourth quarter was the wettestThe wettest periods of the year tend to be the start and the end. In 2023, the fourth quarter was the wettest, with an average of 419 mm of rainfall. October and December of that year recorded the highest monthly rainfall levels at 177 and 189 mm, respectively. Regional weatherDue to the United Kingdom’s geographical location and landscape, weather conditions can vary greatly. Scotland is, on average, the wettest country. Most rainfall is concentrated in the Scottish Highlands, as precipitation often occurs in mountainous regions. As rainfall comes in from the Atlantic, the northern and western parts of the UK are most susceptible to precipitation. This explains why England is the driest of all the regions, as rain deposits reduce as they move east.

The lowest average daily sun hours in the United Kingdom typically occur in January and December. The highest daily sun hours recorded since 2015 was in May 2020, at an average of 9.7 hours per day. In comparison, May 2024 saw 5.6 hours of daily sunshine. High levels of monthly sunlight in 2018 Since 2014, the pattern of total monthly hours of sunlight remained relatively similar up until 2018. That year there was a noticeable increase in sunlight hours in May, June and July – with May recording 241 hours of sunlight. The following year the pattern returned to normal, but a significant increase was again recorded in 2020. Annual sun hours The average annual number of daily sun hours in the UK has remained above four hours per day since 2001, but has not increased above five. Daily sun hours were highest in 2003 at 4.9 hours per day. The following years saw sun hours remain at a similar level, until figures increased again to 4.9 hours in 2022.

Wales usually experiences the highest levels of rainfall in the winter months. Throughout this period, the most rainfall recorded was in December 2015, at ***** millimeters. This was no surprise as there were over ** raindays in this month. A rainday is when there is a total of 1mm or more of rain recorded in a day. Annual rainfallOver the past two decades, the annual rainfall in Wales has fluctuated. The year 2000 experienced the most amount of rain at****** mm. 2010 was the driest year at****** mm. Despite the high levels of rain in Wales, it is not the wettest country in the United Kingdom.********* on average has the most rainfall, with******** being the driest. Sunshine hours With its reputation for rain, sunshine is not the most common sight in Wales. In 2024, the number of total sunshine hours was below the United Kingdom’s average. Typically, May and June register the highest monthly sunshine hours in Wales, with May 2020 seeing a record of ******hours.