Average rainfall in the United Kingdom has generally been higher during the fourth quarter of every year. In the period of consideration, the highest rainfall average was recorded in the fourth quarter of 2011, at 738.6 millimeters.

Between 2001 and 2024, the average rainfall in the United Kingdom varied greatly. In 2010, rainfall dropped to a low of 1,020 millimeters, which was a noticeable decrease when compared to the previous year. However, the following year, rainfall increased significantly to a peak of 1,889 millimeters. During the period in consideration, rainfall rarely rose above 1,500 millimeters. In 2024, the annual average rainfall in the UK surpassed 1,386 millimeters. Monthly rainfall On average, rainfall is most common at the start and end of the year. Between 2014 and 2024, monthly rainfall peaked in December 2015 at approximately 217 millimeters. This was the first of only two times during this period that the average monthly rainfall rose above 200 millimeters. This was a deviation from December’s long-term mean of some 134 millimeters. Rainfall highest in Scotland In the United Kingdom, rain is often concentrated around mountainous regions such as the Scottish Highlands, so it is no surprise to see that – on average – it is Scotland that receives the most rainfall annually. However, in 2024, Wales received the highest rainfall amounting to approximately 1,600 millimeters. Geographically, it is the north and west of the United Kingdom that receives the lion's share of rain, as it is more susceptible to rainfall coming in from the Atlantic.

What does the data show?

The data shows monthly averages of rainfall amount (mm) for 1991-2020 from HadUK gridded data. It is provided on a 2km British National Grid (BNG).

What are the naming conventions and how do I explore the data?

This data contains a field for each month’s average over the period. They are named 'pr' (precipitation) and the month. E.g. 'pr March' is the average rainfall amount for March in the period 1991-2020.

To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578

Please note, if viewing in ArcGIS Map Viewer, the map will default to ‘pr January’ values

Data source:

HadUK-Grid v1.1.0.0 (downloaded 11/03/2022)

Useful links

Further information on HadUK-Grid Further information on understanding climate data within the Met Office Climate Data Portal

Precipitation in the United Kingdom decreased to 1275.23 mm in 2024 from 1405.56 mm in 2023. This dataset includes a chart with historical data for the United Kingdom Average Precipitation.

The United Kingdom experienced an average of ******* millimeters of rainfall in 2024, a decrease of *** percent in comparison to the previous year. While 2024 saw substantial rainfall, it did not surpass the thus-far peak of the century, with ***** millimeters of rain recorded in 2000. Regional variations and seasonal patterns Rainfall distribution across the UK is far from uniform, with Scotland and Wales consistently receiving the highest annual precipitation. In 2024, they recorded an average of ******* millimeters and ******* millimeters, respectively, significantly above the UK’s average. This disparity is largely due to both countries’ mountainous terrain, which is more susceptible to Atlantic weather systems. Seasonally, the wettest months in the UK typically occur in the winter, with the highest precipitation levels seen between November and February. Climate change impact on UK weather Climate change is influencing UK weather patterns, leading to warmer and wetter conditions overall. While annual rainfall fluctuates, there is a trend towards more extreme weather events. For example, 2020 and 2022 saw rain deviations from the long-term mean in the UK of more than 100 millimeters in February. As weather patterns continue to evolve, monitoring rainfall trends remains crucial for understanding and adapting to a changing climate.

What does the data show?

This data shows the monthly averages of rainfall amount (mm) for 1981-2010 from CRU TS (v. 4.06) dataset. It is provided on the WGS84 grid which measures approximately 60km x 60km (latitude x longitude) at the equator. This is the same as the 60km grid used by UKCP18 global datasets.

What are the naming conventions and how do I explore the data?

This data contains a field for each month’s average over the period. They are named 'pr' (precipitation) and the month. E.g. ‘pr March’ is the average of the monthly total rainfall in March throughout 1981-2010.

To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578

Please note, if viewing in ArcGIS Map Viewer, the map will default to ‘pr January’ values.

Data source

CRU TS v. 4.06 - (downloaded 12/07/22)

Useful links

Further information on CRU TS Further information on understanding climate data within the Met Office Climate Data Portal

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.

1 km gridded estimates of daily and monthly rainfall for Great-Britain and Northern Ireland (together with approximately 3000 km2 of catchment in the Republic of Ireland) from 1890 to 2019. The rainfall estimates are derived from the Met Office national database of observed precipitation. To derive the estimates, monthly and daily (when complete month available) precipitation totals from the UK rain gauge network are used. The natural neighbour interpolation methodology, including a normalisation step based on average annual rainfall, was used to generate the daily and monthly estimates. The estimated rainfall on a given day refers to the rainfall amount precipitated in 24 hours between 9am on that day until 9am on the following day. The CEH-GEAR dataset has been developed according to the guidance provided in BS 7843-4:2012.

What does the data show?

The data shows the annual average of precipitation amount (mm) for the 1991-2020 period from HadUK gridded data. It is provided on a 12km British National Grid (BNG).

Limitations of the data

We recommend the use of multiple grid cells or an average of grid cells around a point of interest to help users get a sense of the variability in the area. This will provide a more robust set of values for informing decisions based on the data.

What are the naming conventions and how do I explore the data?

This data contains a field for the average over the 1991-2020 period. It is named 'pr' (precipitation).

To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578

Data source:

·
Version: HadUK-Grid v1.1.0.0 (downloaded 21/06/2022)

·
Source: https://catalogue.ceda.ac.uk/uuid/652cea3b8b4446f7bff73be0ce99ba0f

·
Filename: rainfall_hadukgrid_uk_12km_ann-30y_199101-202012.nc

Useful links

·
Further information on HadUK-Grid

·
Further information on understanding climate data within the Met Office Climate Data Portal

For the purposes of this lesson and those that follow, a specimen data (Monthly Maximum Air Temperatures for 2019 at the 25km resolution) taken from from the HadUK-Grid archive and published as a Feature Layer in ArcGIS OnlineIn this activity we will see how to search ArcGIS Online for data and add it to the Map Viewer.

What does the data show?

This data shows the monthly averages of rainfall amount (mm) for 2040-2069 using a combination of the CRU TS (v. 4.06) and UKCP18 global RCP2.6 datasets. The RCP2.6 scenario is an aggressive mitigation scenario where greenhouse gas emissions are strongly reduced.

The data combines a baseline (1981-2010) value from CRU TS (v. 4.06) with a percentage change relative to 1981-2010 from UKCP18 global. Where the baseline value was <1mm/month, the projection value has been replaced with 'Null' because the percentage change may be unreliable with a very small baseline.

The data is provided on the WGS84 grid which measures approximately 60km x 60km (latitude x longitude) at the equator.

Limitations of the data

We recommend the use of multiple grid cells or an average of grid cells around a point of interest to help users get a sense of the variability in the area. This will provide a more robust set of values for informing decisions based on the data.

What are the naming conventions and how do I explore the data?

This data contains a field for each month’s average over the period. They are named 'pr' (precipitation), the month and ‘upper’ ‘median’ or ‘lower’. E.g. ‘pr Mar Lower’ is the average of monthly-total rainfall in March throughout 2040-2069, in the second lowest ensemble member.

To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578

Please note, if viewing in ArcGIS Map Viewer, the map will default to ‘pr Jan Median’ values.

What do the ‘median’, ‘upper’, and ‘lower’ values mean?

Climate models are numerical representations of the climate system. To capture uncertainty in projections for the future, an ensemble, or group, of climate models are run. Each ensemble member has slightly different starting conditions or model set-ups. Considering all of the model outcomes gives users a range of plausible conditions which could occur in the future.

To select which ensemble members to use, the monthly averages of precipitation for the period 2040-2069 were calculated for each ensemble member and they were then ranked in order from lowest to highest for each location.

The ‘lower’ fields are the second lowest ranked ensemble member. The ‘upper’ fields are the second highest ranked ensemble member. The ‘median’ field is the central value of the ensemble.

This gives a median value, and a spread of the ensemble members indicating the range of possible outcomes in the projections. This spread of outputs can be used to infer the uncertainty in the projections. The larger the difference between the lower and upper fields, the greater the uncertainty.

Data source

CRU TS v. 4.06 - (downloaded 12/07/22)

UKCP18 v.20200110 (downloaded 17/08/22)

Useful links

Further information on CRU TS Further information on the UK Climate Projections (UKCP) Further information on understanding climate data within the Met Office Climate Data Portal

1 km gridded estimates of daily and monthly rainfall for Great-Britain and Northern Ireland (together with approximately 3000 km2 of catchment in the Republic of Ireland) from 1890 to 2015. The rainfall estimates are derived from the Met Office national database of observed precipitation. To derive the estimates, monthly and daily (when complete month available) precipitation totals from the UK rain gauge network are used. The natural neighbour interpolation methodology, including a normalisation step based on average annual rainfall, was used to generate the daily and monthly estimates. The estimated rainfall on a given day refers to the rainfall amount precipitated in 24 hours between 9am on that day until 9am on the following day. The CEH-GEAR dataset has been developed according to the guidance provided in BS 7843-4:2012.

Context Simple time series data for weather prediction time series projects.

Content The data contains the following information from the UK Met Office location at Armagh, Northern Ireland. The data runs from Jan 1853 to Nov 2020 and includes the following monthly data fields:

yyyy = Year mm = Month tmax = Maximum temperature (Celsius) tmin = Minimum temperature (Celsius) af = Count of Air Frost days in the given month rain = Total rainfall (mm) sun = Sunshine duration (hrs) Acknowledgements Provided by the UK Met Office: https://www.metoffice.gov.uk/research/climate/maps-and-data/historic-station-data Available under Open Government Licence: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/

Example code The following Python code will load into a Pandas DataFrame:

colspecs = [(3, 7), (9,11),(14,18),(22,26),(32,34),(37,42),(45,50)] data = pd.read_fwf('../input/heathrow-weather-data/heathrowdata.txt',colspecs=colspecs)

The following will remove the first few lines of text

data = data[3:].reset_index(drop=True) data.columns = data.iloc[1] data = data[3:].reset_index(drop=True)

What does the data show?

This data shows monthly averages of precipitation (mm/day) for 2050-2079 from the UKCP18 regional climate projections. The data is for the high emissions scenario (RCP8.5).

Limitations of the data

We recommend the use of multiple grid cells or an average of grid cells around a point of interest to help users get a sense of the variability in the area. This will provide a more robust set of values for informing decisions based on the data.

What are the naming conventions and how do I explore the data?

This data contains a field for each month’s average over the period. They are named 'pr' (precipitation), the month, and 'upper' 'median' or 'lower'. E.g. 'pr July Median' is the median value for July.

To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578

Please note, if viewing in ArcGIS Map Viewer, the map will default to ‘pr January Median’ values.

What do the ‘median’, ‘upper’, and ‘lower’ values mean?

Climate models are numerical representations of the climate system. To capture uncertainty in projections for the future, an ensemble, or group, of climate models are run. Each ensemble member has slightly different starting conditions or model set-ups. Considering all of the model outcomes gives users a range of plausible conditions which could occur in the future.

For this dataset, the model projections consist of 12 separate ensemble members. To select which ensemble members to use, the monthly averages of precipitation for 2050-2079 were calculated for each ensemble member and they were then ranked in order from lowest to highest for each location.

The ‘lower’ fields are the second lowest ranked ensemble member. The ‘upper’ fields are the second highest ranked ensemble member. The ‘median’ field is the central value of the ensemble.

This gives a median value, and a spread of the ensemble members indicating the range of possible outcomes in the projections. This spread of outputs can be used to infer the uncertainty in the projections. The larger the difference between the lower and upper fields, the greater the uncertainty.

Data source

pr_rcp85_land-rcm_uk_12km_12_mon-30y_200912-207911.nc (median)

pr_rcp85_land-rcm_uk_12km_05_mon-30y_200912-207911.nc (lower)

pr_rcp85_land-rcm_uk_12km_04_mon-30y_200912-207911.nc (upper)

UKCP18 v20190731 (downloaded 04/11/2021)

Useful links

Further information on the UK Climate Projections (UKCP). Further information on understanding climate data within the Met Office Climate Data Portal

Rainfall in England amounted to *** millimeters in February 2020. This was the most rainfall recorded in a single month during the period of consideration. Meanwhile, the driest month during this period was in May 2020, in which less than ** millimeters of rain fell. In April 2025, England's precipitation amounted to **** millimeters, a decrease of ** percent in comparison to the same month the previous year.

Context

Simple time series data for weather prediction time series projects.

Content

The data contains the following information from the UK Met Office location at London Heathrow Airport. The data runs from Jan 1948 to Oct 2020 and includes the following monthly data fields:

• yyyy = Year
• mm = Month
• tmax = Maximum temperature (Celsius)
• tmin = Minimum temperature (Celsius)
• af = Count of Air Frost days in the given month
• rain = Total rainfall (mm)
• sun = Sunshine duration (hrs)

Acknowledgements

Provided by the UK Met Office: https://www.metoffice.gov.uk/research/climate/maps-and-data/historic-station-data Available under Open Government Licence: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/

Example code

The following Python code will load into a Pandas DataFrame:

colspecs = [(3, 7), (9,11),(14,18),(22,26),(32,34),(37,42),(45,50)] data = pd.read_fwf('../input/heathrow-weather-data/heathrowdata.txt',colspecs=colspecs)

The following will remove the first few lines of text

data = data[3:].reset_index(drop=True) data.columns = data.iloc[1] data = data[3:].reset_index(drop=True)

Licence information and source

The MET Office copyright policy can be found at: [https://www.metoffice.gov.uk/about-us/legal#licences] Data source from: [https://www.metoffice.gov.uk/research/climate/maps-and-data/historic-station-data]

Cover image: [https://pixabay.com/photos/scarborough-sunrise-seascape-2850597/]

Monthly reports. Contains maps and data for England, Wale, Scotland and Northern Ireland

What does the data show?

The data shows monthly averages of surface temperature (°C) for 1991-2020 from HadUK gridded data. It is provided on a 12km British National Grid (BNG).

Limitations of the dataWe recommend the use of multiple grid cells or an average of grid cells around a point of interest to help users get a sense of the variability in the area. This will provide a more robust set of values for informing decisions based on the data.What are the naming conventions and how do I explore the data?

This data contains a field for each month’s average over the period. They are named 'tas' (temperature at surface) and the month. E.g. 'tas March' is the average surface temperature for March in the period 1991-2020.

To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578

Please note, if viewing in ArcGIS Map Viewer, the map will default to ‘tas January’ values.

Data source:

·
Version: HadUK-Grid v1.1.0.0 (downloaded 21/06/2022)

·
Source: https://catalogue.ceda.ac.uk/uuid/652cea3b8b4446f7bff73be0ce99ba0f

·
Filename: tas_hadukgrid_uk_12km_mon-30y_199101-202012.nc

Useful links

·
Further information on HadUK-Grid

·
Further information on understanding climate data within the Met Office Climate Data Portal

What does the data show?

This data shows annual averages of precipitation (mm/day) for 2050-2079 from the UKCP18 regional climate projections. The data is for the high emissions scenario (RCP8.5).

Limitations of the data

We recommend the use of multiple grid cells or an average of grid cells around a point of interest to help users get a sense of the variability in the area. This will provide a more robust set of values for informing decisions based on the data.

What are the naming conventions and how do I explore the data?

This data contains a field for the average over the period. They are named 'pr' (precipitation), the month, and 'upper' 'median' or 'lower'. E.g. 'pr Median' is the median value.

To understand how to explore the data, see this page: https://storymaps.arcgis.com/stories/457e7a2bc73e40b089fac0e47c63a578

Please note, if viewing in ArcGIS Map Viewer, the map will default to ‘pr January Median’ values.

What do the ‘median’, ‘upper’, and ‘lower’ values mean?

Climate models are numerical representations of the climate system. To capture uncertainty in projections for the future, an ensemble, or group, of climate models are run. Each ensemble member has slightly different starting conditions or model set-ups. Considering all of the model outcomes gives users a range of plausible conditions which could occur in the future.

For this dataset, the model projections consist of 12 separate ensemble members. To select which ensemble members to use, the annual averages of precipitation for 2050-2079 were calculated for each ensemble member and they were then ranked in order from lowest to highest for each location.

The ‘lower’ fields are the second lowest ranked ensemble member. The ‘upper’ fields are the second highest ranked ensemble member. The ‘median’ field is the central value of the ensemble.

This gives a median value, and a spread of the ensemble members indicating the range of possible outcomes in the projections. This spread of outputs can be used to infer the uncertainty in the projections. The larger the difference between the lower and upper fields, the greater the uncertainty.

Data source

pr_rcp85_land-rcm_uk_12km_12_ann-30y_200912-207911.nc (median)

pr_rcp85_land-rcm_uk_12km_05_ann-30y_200912-207911.nc (lower)

pr_rcp85_land-rcm_uk_12km_04_ann-30y_200912-207911.nc (upper)

UKCP18 v20190731 (downloaded 04/11/2021)

Useful links

Further information on the UK Climate Projections (UKCP). Further information on understanding climate data within the Met Office Climate Data Portal