The Atlas shows regional climate conditions projected to occur if Earth’s long-term average temperature reaches specific levels of warming. These Global Warming Levels (GWLs) correspond to global average temperature increases of 1.5, 2, 3, and 4 degrees Celsius above pre-industrial levels measured from 1851 to 1900. On the Fahrenheit scale, these warming levels are 2.7, 3.6, 5.4, and 7.2 °F. As of the 2020s, global average temperature has already increased around 2 °F above pre-industrial levels. County projections for each global warming level were calculated by identifying the year when individual climate models reach that level. The projections were then averaged with the 9 previous years and the 10 subsequent years to represent the climatic state for that period. Using a 30-year average avoids focusing on a shorter period that may be warmer or cooler than the two-decade average. Projections for all GWLs are based on the same fossil-fuel intensive scenario, SSP5-8.5.Variables IncludedDaily temperature and precipitation projections were used to calculate more decision-relevant thresholds of climate exposure, which are available in this feature layer. The data variables and field names in this feature layer were used to create the maps found in the NCA Interactive Atlas Explorer. Name of Map Description of the variableVariable Field NameChange in Average Annual TemperatureAverage temperature (daily high + daily low/2) for the entire yearTemperature averageChange in Average Annual Maximum TemperatureAverage of the highest temperature of the day over a full yearTemp Annual MaxChange in Mean Summer TemperatureAverage temperature (daily high + daily low/2) during June, July, & AugustTemp mean summer Change in Temperature on the Hottest Day of the Year Highest temperature on the hottest day of the year Temp max 1-dayChange in Lowest Temperatures of SummerAverage of the lowest temperature of the day during June, July, AugustTemp min summerChange in the Number of Days Over 95°FDays per year with an afternoon high temperature of at least 95°FTemp Days 95 FChange in the Number of Days Over 100°FDays per year with an afternoon high temperature of at least 100°FTemp Days 100 FChange in the Number of Days Over 105°FDays per year with an afternoon high temperature of at least 105°FTemp Days 105 FChange in the Number of Warm NightsDays per year when the overnight low is 70°F or warmerTemp Days Min 70 FChange in the Number of Days Under 32 deg FDays per year when the lowest temperature is below freezingTemp Days Min 32 FChange in the Number of Days below 0°FDays per year when the lowest temperature is well below freezingTemp Days Min 0 FChange in Annual PrecipitationTotal precipitation over a full yearPrecip AnnualChange in Extreme Precipitation Total precipitation over a year that arrives on days when the daily total is in the top 1% of historical amountsPrecip Above 99th pctlChange in Days with Extreme PrecipitationDays per year when precipitation totals are in the top 1% of historical amountsPrecip Days 99 pctlChange in Precipitation on the Wettest Day of the YearHighest daily precipitation total of the yearPrecip 1-day maxChange in Precipitation on the Wettest Day in 5 YearsHighest daily precipitation total over five yearsPrecip 5-year maxCoastal Inundation related to Sea Level RiseAreas projected to be below sea level in 2100SLR_InundationDownscaled Climate ProjectionsProjections in the Atlas are from global climate models that participated in Phase 6 of the Coupled Model Intercomparison Project (CMIP6). To make the CMIP6 projections more relevant at regional-to-local scales, results from global models were spatially downscaled using statistical methods documented by LOCA2 and STAR-ESDM. Note that climate projections are not weather forecasts for specific dates in the future—rather, they describe potential climate conditions for future decades based on plausible scenarios of human actions.Climate Projections for States and Territories Outside the Contiguous United StatesThe availability of downscaled climate projections for geographies outside of the contiguous United States is limited. For locations in Alaska, Hawai‘i, and Puerto Rico, the Atlas includes global data from CMIP6 and downscaled data from STAR-ESDM for selected weather stations. Specifically, where downscaled data are not available, the Atlas includes results from an ensemble of individual models in the scenario model intercomparison project (ScenarioMIP).More details are available from the NCA Interactive Atlas site.

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.

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.