Welcome to Climate Explorer
Please read: To tackle increasing web traffic from spambots blocking the server for legitimate users, we are asking users to now verify that they are human before using the Climate Explorer. You will only have to do this once for a given computer or network. This is not related to your user ID. Please contact the administrator if you run into problems with this service, or wish to have your IP address manually added to our system.
About the Climate Explorer
The KNMI Climate Explorer is a web-based scientific analysis tool developed and maintained by the Royal Netherlands Meteorological Institute (KNMI). It is designed to help researchers, students, and climate analysts explore, analyze, and visualize climate data from a wide range of sources. The tool is freely accessible online and is widely used in climate science, especially for studying climate variability and change. The Climate Explorer is freely accessible and is widely used in climate science, especially for studying climate variability and change.
The Climate Explorer is part of the WMO Regional Climate Centre at KNMI. It contains more than 10 TB of climate data and dozens of analysis tools to provide an interactive environment for climate data exploration and statistical analysis. These include
- Surface temperature records from weather stations worldwide
- Precipitation data
- Atmospheric pressure and wind observations
- Reanalysis of datasets (combined observations and model reconstructions of past weather)
- Outputs from global climate models (such as CMIP experiments)
- Future climate scenario simulations
Much of the observational data is updated monthly, part of the daily data is updated every day. Other data is updated when needed. If you have an interesting dataset that you want us to consider for publishing on the KNMI Climate Explorer, please send us the URL of a CF-compliant netcdf file and a short description. Note that publishing is not guaranteed and is at the discretion of the maintainers.
The Climate Explorer provides several built-in analysis tools for working directly with climate data in your browser. Users can generate time series to examine climate variability and trends, including anomaly calculations relative to a reference period. Analysis is available to compare average climate conditions during selected events or periods, such as extreme weather years or known climate phases. Trend analysis tools allow calculation of long-term changes, paired with significance testing to assess robustness. Results from all analyses can be visualized and downloaded for further use.
The code of the KNMI Climate Explorer itself is freely available on GitLab.
Your first time with the Climate Explorer
New users are adviced to study the examples and the manual. There is also an old presentation available that gives an overview of the system, and a more recent video presentation focussing mainly on the Atlas. Trouet and van Oldenborgh (TRR, 2013) gives a useful overview and manual for paleo-climatologists and others who try to understand the influence of climate on their time series.In the Climate Explorer pages, the 
symbol indicates a help pop-up. Below an alphabetical list of these pop-ups is given. Please contact the administrator if the help text is confusing, or missing in a place where it is needed.
- temperature data and precipitation data: find and analyse for a point location: station data, gridded data, reanalysis data.
- assessing and downloading data: sign in; assess data; investigate time series; create extremes series; download (processed) data; gridded data; select subregion; create time series of extreme index; trend analysis.
- attribution protocol: Create map of the event; Create map of rank; Create climatology map; Create time series from field; Plot last N days; Generate extreme time series; Plot 15-year running standard deviation /dispersion; Calculate trends in return times of extremes; model evaluation and attribution; synthesis of attribution results.
Do not forget to cite the KNMI Climate Explorer in your publications!
Citation of the Climate Explorer
It is much easier for us to get funded to maintain the KNMI Climate Explorer if it is cited in scientific journals. Academic tradition requires you to cite works you base your article on. If you use the KNMI Climate Explorer to process data for an article in a scientific publication, please cite:
KNMI Climate Explorer. c2022. de Bilt: Koninklijk Nederlands Meteorologisch Instituut (KNMI); [accessed 2025 Nov 17]. https://climexp.knmi.nl/start.cgi.
This example (change the access date as needed) is based on the 'Scientific Style and Format Citation Quick Guide' from the Council of Science Editors. Please adapt to your journal guidelines.
In publications the original data source should also be cited. The Climate Explorer provides a link to a web page describing the data. If this link is broken, please let us know and we will try to fix it.
Contact us!
The support team of the KNMI Climate Explorer originally consisted of one research scientist, next to his day job writing research papers. He supported the Climate Explorer and related projects.The Climate Explorer relies on the users to report bugs, please mail the administrator when something does not work as advertised.
Some restrictions are in force: the site does not remember how you filled out the forms, you cannot define your own indices, nor upload data into the Climate Explorer or handle large datasets. If you want to use these features please log in or register.
Recent news
This is an excerpt of our most recent news, announcements, and updates.| News | |
|---|---|
| 14-sep-2026 | Updated UK Met Office datasets CRUTEM (5.1), ISST2 (2.2), HadSST (4.2), HadNMAT2 (2.0.1) |
| 01-sep-2026 | Updated E-OBS global radiation to version 31 |
| 01-sep-2026 | Updated E-OBS to version 33 (32 for wind speed, and global radiation remains at 30) |
| 01-sep-2026 | Upgraded CRU TS and scPDSI to their 4.10 version running up to 2025 |
| 26-jan-2026 | Add global (0.5°) and regional (0.25°) daily dPET from Bristol University |
| 12-jan-2026 | Update and add new cyclones data sets from Colorado State University |
| 09-jan-2026 | Add global daily dPET derived from ERA5-Land from Bristol University (experimental, 0.5° only) |
| 30-oct-2025 | Climate Explorer experienced a server issue this morning. The issue has now been resolved and service has returned to normal. |
| 06-oct-2025 | Add E-OBS 0.1 degree |
| 06-oct-2025 | The cluster platform used by the Climate Explorer has been updated |
| 09-sep-2025 | Updated soil moisture from Land Data Assimilation System (FLDAS) up to last month |
| 09-jul-2025 | Climate Explorer has recently undergone maintenance and upgrades to allow future improvemenets. If you encounter any issues with the site, please report them to the administrator. |
| 26-may-2025 | Updated E-OBS to version 31 (30 for global radiation) |
| 19-may-2025 | Added HadEX3 analyses of extreme indices (replaces HadEx2) |
| 17-apr-2025 | A new side menu section Toolbox Attribution Studies has been added with the existing Attribution Runs feature and two new tools - Analogues and Synthesis. |
| 04-feb-2025 | We will soon be deploying a new IP whitelisting feature in an attempt to block automated spam traffic and hopefully improve performance for legitimate users. This will require you to click on a confirmation button. After clicking, you will not be asked again until you change network (e.g. connect to a VPN, travel to another location). We will not require any personal information during this process. Please report problems you encounter to the administrator. |
| 16-dec-2024 | Climate Change Atlas updated to include KNMI23 CMIP6 data and AR6 regions. You may have to refresh your browser to see the new version. Please report issues to the administrator. |
| 28-oct-2024 | Provide PDO from HadISST, COBE2 and ERSST5 |
| 28-oct-2024 | Updated E-OBS to the Copernicus version 30.0e |
| 07-oct-2024 | Look and feel of side menu reworked. You may need to refresh your browser for the changes to take effect. Please report issues to the administrator. |
| more... | |
icons.
| Updates | |
|---|---|
| 16-dec-2024 | Climate Change Atlas updated to include KNMI23 CMIP6 data and AR6 regions. You may have to refresh your browser to see the new version. Please report issues to the administrator. |
| 11-apr-2022 | The Climate Change Atlas is converted to use python3. |
| 14-mar-2022 | Fix for plots with transparancy (ghostscript options) and maps (updated version of NCL) in the Climate Change Atlas. |
| 03-mar-2022 | Applied fix for plotting time series with the Climate Change Atlas and a fix for creating country masks that were not created in advance. |
| 14-oct-2021 | In memoriam Geert Jan van Oldenborgh. With deepest sadness, we share with you that Geert Jan van Oldenborgh (59), initiator, creator and maintainer of the Climate Explorer, sadly passed away on Tuesday 12 October. Geert Jan's contribution to climate science is immense and he will be sorely missed. |
| 30-apr-2021 | Updated the Atlas to use ERA5, HadCRUT5 and 20CRv3. |
| 04-jun-2020 | Making time series plots in the Atlas with tranaparancy works again (thanks Michael). |
| 27-may-2019 | Fixed colour scale of Atlas sea level pressure plots (thanks Indrani). |
| 16-may-2019 | The bugfix of two days ago does not work properly and I cannot find one that does, so I turned off PDF generation for Atlas time series for the time being. Please use the EPS or PNG plots. |
| 14-may-2019 | Fixed a bug in the Atlas time sersies that I called the system ghostscript that does not support transparency, now call the one that does (thanks Michael). |
| 18-apr-2019 | Added Reconstructed scPDSI for Australia/New Zealand Drought Atlas (thanks Jonathan) |
| 28-dec-2017 | Fixed a bug in the Atlas that caused regressions not to work (thanks Simon). |
| 11-jul-2018 | Chromium seems to submit forms twice, which can lead to corrupted data. I am trying to eliminate that but use another browser for the time being. |
| 07-nov-2018 | Fixed a bug that caused mysterious error messages in time series generation. |
| 09-feb-2018 | Added SREX masks for temperature observation analysis (thanks Wagner). |
| 07-jan-2018 | For two weeks incorrectly propagated metadata in time series could have caused problems. This should be fixed now. |
| 14-dec-2016 | Fixed a bug that prevented 20CR timeseries from being plotted. |
| 12-dec-2016 | Fixed a bug that prevented extreme plots from appearing (thanks Sjoukje). |
| 17-may-2016 | Fixed a bug that caused time series computations to stop with "reanalysis boundaries" (thanks Ousmane). |
| 16-may-2016 | Added EUR-44 CORDEX data to the Climate Explorer and Atlas (thanks Urs). |
| 12-jan-2016 | The storage server from which the Climate Explorer gets its data will be rebooted this day. This may degrade performance a bit. |
| 05-jan-2016 | Added IPBES regions and subregions. |
| 04-jan-2016 | Deleted spurious lines in the maps of Italy, Kyrgyzstan, Mozambique, South Africa, United Arab Emirates and Uzbeikstan. |
| 04-jan-2016 | The Atlas now also uses the whole page rather than only 800 pixels. |
| 27-nov-2015 | Deleted the country Readme between Qatar and Romania (thanks Boris). |
| 05-nov-2015 | The Atlas cache has been moved to a new data store, this should not make much difference. |
| 24-sep-2015 | Deleted the MIRO-ESM and MIROC-ESM-CHEM Txx as it reached 80 °C in the deserts. |
| 15-sep-2015 | Question: would RCM data (eg from CORDEX) be useful in the Atlas? Please contact me if you need other data. |
| 12-may-2015 | Fixed a bug in the KNMI Climate Change Atlas: time series of some countries could not be computed (thanks Paul). |
| 12-may-2015 | Fixed a bug in the KNMI Climate Change Atlas: RCP4.5/RCP6.0/RCP8.5 combined maps did not plot for the full CMIP5 ensemble (thanks Paul). |
| 31-jan-2014 | Fixed bug that absolute and relative regression trend maps had the same file name, whichever was computed first would always be shown. |
| 31-dec-2014 | Added states of the US. |
| 20-aug-2014 | Removed INMCM4 and IPSL-CM5B-LR from the fd (frost days) ensemble because they have far too many frost days in tropical regions and Europe (thanks Claudia). |
| 15-aug-2014 | Changed the presentation of differences in extreme variables that count the number of days (frost days, ice days, ...), so that areas with less than one day per year in the current climate stay white (thanks Claudia). |
| 10-jul-2014 | Fixed a bug in the trends (regressions) where only one percentile plot was shown as the name was not unique across percentiles. |
| 23-may-2014 | Upgraded CRU TS to version 3.21 (thanks Michael). |
| 22-may-2014 | Fixed a bug introduced two days ago that prevented time series of seasons being computed (thanks Michael). |
| 20-may-2014 | Fixed a bug that prevented non-linear trends of annual (extreme) data to be computed. |
| 20-may-2014 | Fixed a bug that prevented time series of relative anomalies annual time series to be computed. |
| 19-may-2014 | Switched to the CCCMA altcdd and altcwd to avoid problems in 2005 and 2006 in almost always dry/wet regions (thanks Slava). |
| 19-may-2014 | Maps with the combined scenarios RCP4.5/RCP6.0/RCP8.5 now also work for extremes, where it is most useful (thanks Andreas). |
| 14-may-2014 | Fixed a bug that for time series the scenarios would always be selected if they had once been selected (thanks Albert). |
| 09-jan-2014 | Changed the way countries are treated: if a region (island) is too small to have a grid point in the interior it contributes proportional to its area. This way small countries still give a result, even though it may not be completely representative of the area of the country itself. |
| 03-jan-2014 | Added all countries and autonomous regions of the world to the list of predefined regions. Please let me know if you prefer to have sub-categaries like I made for the Netherlands, France. |
| 22-dec-2013 | Added soil moisture, please note that the reliability is not very high. |
| 06-dec-2013 | Implemented remembering forms for nonimous users. This shoudl also improve the user experience on tablets and smartphones. |
| 28-nov-2013 | Added CCCMA ETCCDI CMIP5 annual extremes, it looks as if I have fixed the bugs, please let me know if you find suspicious results. |
| 21-nov-2013 | Added CMIP5 relative humidity. |
| 16-nov-2013 | Added observational datasets. |
| 13-nov-2013 | Added ERA-interim, 20CR. |
| 13-nov-2013 | Added CMIP3. |
| 13-nov-2013 | Regression-based trends also work now. |
| 06-nov-2013 | Time series of relative changes over non-standard meteorological seasons still had a problem up to now, fixed (thanks Maarten). |
| 06-nov-2013 | Time series now work well for relative and absolute values as far as I can see. Please disregard results obtained before now. |
| 06-nov-2013 | Maps did not work for half a day due to a typo. |
| 01-nov-2013 | I think I got the time series section to work as well. Please report bugs. |
| 26-oct-2013 | Added evaporation, net water flux (P-E), Tmin, Tmax, specific humidity, surface solar radiation (downward) and sea-level pressure. |
| 25-oct-2013 | Maps of differences of temperature and precipitation of other lengths now also include hatching. |
| 17-oct-2013 | Maps of 20-yr differences of temperature and precipitation work and for the seasons in the IPCC WG1 Ar5 Annex I "Atlas" give the same results. |