# \#api **URL:** https://forum.ecmwf.int/tag/api/56.md [Latest](https://forum.ecmwf.int/latest.md) · [Categories](https://forum.ecmwf.int/categories.md) · [Tags](https://forum.ecmwf.int/tags.md) --- ## [403 Client Error while downloading 1 day of Europe constrained ERA5 data](https://forum.ecmwf.int/t/403-client-error-while-downloading-1-day-of-europe-constrained-era5-data/15337)
**Author:** [@Sofia\_Gomez\_Maqueo\_Anaya](https://forum.ecmwf.int/u/Sofia_Gomez_Maqueo_Anaya)\ **Replies:** 12\ **Last updated:** [13 October 2026 00:29 UTC](https://forum.ecmwf.int/t/403-client-error-while-downloading-1-day-of-europe-constrained-era5-data/15337 "2026-10-13T00:29:16Z")
Hi all, I am trying to download ERA5 data using api as a public user. I had downloaded the same dataset before a few times now and I had not encountered this error until now. The downloading of the data is done through… --- ## [ECMWF APIs (FAQ, API + data documentation)](https://forum.ecmwf.int/t/ecmwf-apis-faq-api-data-documentation/6880)
**Author:** [@Koen\_Hufkens](https://forum.ecmwf.int/u/Koen_Hufkens)\ **Replies:** 8\ **Last updated:** [12 October 2026 12:01 UTC](https://forum.ecmwf.int/t/ecmwf-apis-faq-api-data-documentation/6880 "2026-10-12T12:01:46Z")
Below you find a centralized compilation of key documentation on the new ECMWF APIs as cross-posted from ECMWF API use | BlueGreen Labs. I will only use the CDS as a reference, but the same applies to ADS and EWDS. The … --- ## [Downloading ERA5-Land data via cdsapi takes a long time in the queue](https://forum.ecmwf.int/t/downloading-era5-land-data-via-cdsapi-takes-a-long-time-in-the-queue/15348)
**Author:** [@wanjia\_sun](https://forum.ecmwf.int/u/wanjia_sun)\ **Replies:** 5\ **Last updated:** [9 October 2026 16:47 UTC](https://forum.ecmwf.int/t/downloading-era5-land-data-via-cdsapi-takes-a-long-time-in-the-queue/15348 "2026-10-09T16:47:37Z")
This is my first time using cdsapi to download global daily 2 m temperature data from the “ERA5-Land post-processed daily statistics from 1950 to present” dataset. I submit requests one month at a time, with three reques… --- ## [Python package to (hopefully) retrieve data without cdsapi 403 Client Error](https://forum.ecmwf.int/t/python-package-to-hopefully-retrieve-data-without-cdsapi-403-client-error/15396)
**Author:** [@Lorenzo\_Luca\_Donati](https://forum.ecmwf.int/u/Lorenzo_Luca_Donati)\ **Replies:** 0\ **Last updated:** [9 October 2026 11:03 UTC](https://forum.ecmwf.int/t/python-package-to-hopefully-retrieve-data-without-cdsapi-403-client-error/15396 "2026-10-09T11:03:04Z")
Hello, I was having troubles downloading model level data from different locations. I needed data for two years and it had suddenly become impossible because CDS changed the retrieval limit to something quite low (max 1… --- ## [Recommended strategy for bulk downloads](https://forum.ecmwf.int/t/recommended-strategy-for-bulk-downloads/14888)
**Author:** [@David\_Orme](https://forum.ecmwf.int/u/David_Orme)\ **Replies:** 9\ **Last updated:** [26 September 2026 15:49 UTC](https://forum.ecmwf.int/t/recommended-strategy-for-bulk-downloads/14888 "2026-09-26T15:49:02Z")
Hi, I wanted to ask if there is a preferred or recommended approach for downloading bulk data. I’ve been tasked to download 46 years of hourly data for 10 variables from the global ERA5 single level 0.25° resolution dat… --- ## [Short video guide on How to use CDS API released!](https://forum.ecmwf.int/t/short-video-guide-on-how-to-use-cds-api-released/15353)
**Author:** [@Anabelle](https://forum.ecmwf.int/u/Anabelle)\ **Replies:** 0\ **Last updated:** [23 September 2026 16:31 UTC](https://forum.ecmwf.int/t/short-video-guide-on-how-to-use-cds-api-released/15353 "2026-09-23T16:31:31Z")
As part of our ongoing efforts to continuously improve support to our users, we are pleased to announce the release today, 24 September 2026, of a new short video guide on using the Climate Data Store (CDS) API. The vide… --- ## [CORDEX Downloading - Slower after July update](https://forum.ecmwf.int/t/cordex-downloading-slower-after-july-update/15229)
**Author:** [@Mattia\_Donato](https://forum.ecmwf.int/u/Mattia_Donato)\ **Replies:** 6\ **Last updated:** [6 August 2026 14:24 UTC](https://forum.ecmwf.int/t/cordex-downloading-slower-after-july-update/15229 "2026-08-06T14:24:45Z")
Dear All, I have been downloading CORDEX data via API and it seems very slow recently. Has anyone encountered a similar issue? Thank you --- ## [CAMS global atmospheric composition forecasts very slow](https://forum.ecmwf.int/t/cams-global-atmospheric-composition-forecasts-very-slow/15157)
**Author:** [@Alessandro\_D\_Ausilio1](https://forum.ecmwf.int/u/Alessandro_D_Ausilio1)\ **Replies:** 1\ **Last updated:** [20 July 2026 11:49 UTC](https://forum.ecmwf.int/t/cams-global-atmospheric-composition-forecasts-very-slow/15157 "2026-07-20T11:49:09Z")
I am trying to download the cams global forecast data for the year 2025 using the API and it is very slow. One request took 12 hours (“request-id”: “25730c4d-8afc-4bc7-ac01-e567cf9b2239”) I wonder if this is something e… --- ## [The CDS server broke right now? I can't enter.](https://forum.ecmwf.int/t/the-cds-server-broke-right-now-i-cant-enter/15183)
**Author:** [@HAOYU\_CHEN](https://forum.ecmwf.int/u/HAOYU_CHEN)\ **Replies:** 2\ **Last updated:** [20 July 2026 11:11 UTC](https://forum.ecmwf.int/t/the-cds-server-broke-right-now-i-cant-enter/15183 "2026-07-20T11:11:31Z")
The CDS server broke right now? I can’t enter. --- ## [Era5 data for Namibia 2024](https://forum.ecmwf.int/t/era5-data-for-namibia-2024/15170)
**Author:** [@Lukas\_Wolff](https://forum.ecmwf.int/u/Lukas_Wolff)\ **Replies:** 1\ **Last updated:** [17 July 2026 15:28 UTC](https://forum.ecmwf.int/t/era5-data-for-namibia-2024/15170 "2026-07-17T15:28:43Z")
Hi, I tried to download era5 hourly time series for irradiance and temperatures for Namibia in 2024. It appears that some of the data points in october are doubled in the database. The same issue does not occur with the… --- ## [Spatial subsetting of CORDEX data](https://forum.ecmwf.int/t/spatial-subsetting-of-cordex-data/1411)
**Author:** [@Patrick\_Van\_Laake](https://forum.ecmwf.int/u/Patrick_Van_Laake)\ **Replies:** 3\ **Last updated:** [10 July 2026 11:14 UTC](https://forum.ecmwf.int/t/spatial-subsetting-of-cordex-data/1411 "2026-07-10T11:14:46Z")
Hello all, I am trying to put together a simple subsetting operation on CORDEX data. It is effectively the simplest data retrieval command followed by ct.cube.select(data, extent=\[28., 42., -3., 0.\]). The app, however, … --- ## [Issue with Downloading ERA5 Pressure-Level Data via the CDS API](https://forum.ecmwf.int/t/issue-with-downloading-era5-pressure-level-data-via-the-cds-api/15098)
**Author:** [@sim\_seonmi](https://forum.ecmwf.int/u/sim_seonmi)\ **Replies:** 0\ **Last updated:** [24 June 2026 08:01 UTC](https://forum.ecmwf.int/t/issue-with-downloading-era5-pressure-level-data-via-the-cds-api/15098 "2026-06-24T08:01:30Z")
hello. I’m downloading ERA5 vertical profile data using the CDS API, but the download time has become extremely long. I’m using the “derived-era5-pressure-levels-daily-statistics” dataset and need all pressure levels. … --- ## [How to Download Faster](https://forum.ecmwf.int/t/how-to-download-faster/1391)
**Author:** [@Joseph\_Janssen](https://forum.ecmwf.int/u/Joseph_Janssen)\ **Replies:** 20\ **Last updated:** [9 June 2026 11:14 UTC](https://forum.ecmwf.int/t/how-to-download-faster/1391 "2026-06-09T11:14:03Z")
I am downloading a lot of data from the ERA5 dataset. I am downloading 20 years of temperature/precipitation data for a few thousand small regions. How do I do this quickly? It seems that the download time for each regio… --- ## [S2S manage licenses](https://forum.ecmwf.int/t/s2s-manage-licenses/15048)
**Author:** [@Jeff\_Turmelle](https://forum.ecmwf.int/u/Jeff_Turmelle)\ **Replies:** 0\ **Last updated:** [5 June 2026 07:43 UTC](https://forum.ecmwf.int/t/s2s-manage-licenses/15048 "2026-06-05T07:43:53Z")
I’ve accepted all the licenses, but still get an error message with my API key: Not all the required licences have been accepted when I try to access any of the S2S datasets. --- ## [AIFS Single v2 and AIFS ENS v2](https://forum.ecmwf.int/t/aifs-single-v2-and-aifs-ens-v2/14907)
**Author:** [@hyy](https://forum.ecmwf.int/u/hyy)\ **Replies:** 2\ **Last updated:** [14 May 2026 10:51 UTC](https://forum.ecmwf.int/t/aifs-single-v2-and-aifs-ens-v2/14907 "2026-05-14T10:51:39Z")
Hello, while visualizing the test data for AIFS single v2 on the OpenData webpage, we unexpectedly discovered that the new AIFS model’s 06z and 12z showed abnormal differences in the simulation of the Northwest Pacific i… --- ## [Cdsapi and limitations?](https://forum.ecmwf.int/t/cdsapi-and-limitations/14916)
**Author:** [@Etienne\_WATTEBLED](https://forum.ecmwf.int/u/Etienne_WATTEBLED)\ **Replies:** 1\ **Last updated:** [11 May 2026 13:56 UTC](https://forum.ecmwf.int/t/cdsapi-and-limitations/14916 "2026-05-11T13:56:13Z")
Hello, What are cds api limitations please ? number of data, number of calls and so on ? For this link : https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels And I found t… --- ## [CDS API not working](https://forum.ecmwf.int/t/cds-api-not-working/14010)
**Author:** [@Mriganka\_Biswas](https://forum.ecmwf.int/u/Mriganka_Biswas)\ **Replies:** 8\ **Last updated:** [30 April 2026 08:49 UTC](https://forum.ecmwf.int/t/cds-api-not-working/14010 "2026-04-30T08:49:34Z")
I am trying to download ‘cams-global-atmospheric-composition-forecasts‘ dataset using CDS API. However I am getting the following error ”” requests.exceptions.HTTPError: 404 Client Error: Not Found for url: https://cds.… --- ## [TIGGE perturbed forecast download - job status "running" for 24h](https://forum.ecmwf.int/t/tigge-perturbed-forecast-download-job-status-running-for-24h/14924)
**Author:** [@Victoria\_Marti](https://forum.ecmwf.int/u/Victoria_Marti)\ **Replies:** 0\ **Last updated:** [29 April 2026 14:57 UTC](https://forum.ecmwf.int/t/tigge-perturbed-forecast-download-job-status-running-for-24h/14924 "2026-04-29T14:57:32Z")
Hi, I’ve been trying to download data from the TIGGE dataset (especifically UKMO perturbed forecasts). As we are in the overlap phase during the migration of the dataset, I tried to download it from the ECMWF Public Dat… --- ## [Incomplete SEAS5.1 (ECMWF 51) seasonal forecasts dataset (March 1st init)](https://forum.ecmwf.int/t/incomplete-seas5-1-ecmwf-51-seasonal-forecasts-dataset-march-1st-init/14866)
**Author:** [@Giorgia\_Di\_Capua](https://forum.ecmwf.int/u/Giorgia_Di_Capua)\ **Replies:** 2\ **Last updated:** [24 April 2026 11:09 UTC](https://forum.ecmwf.int/t/incomplete-seas5-1-ecmwf-51-seasonal-forecasts-dataset-march-1st-init/14866 "2026-04-24T11:09:38Z")
Dear all, I’ve been working with SEAS5(.1) for a several years and so far I had no issue with the download process. I wanted to update my dataset and notice that 2024 and 2025 contained more ensemble members. So I check… --- ## [ERA5T actual download availability](https://forum.ecmwf.int/t/era5t-actual-download-availability/14896)
**Author:** [@Aaron\_Spring](https://forum.ecmwf.int/u/Aaron_Spring)\ **Replies:** 0\ **Last updated:** [23 April 2026 10:25 UTC](https://forum.ecmwf.int/t/era5t-actual-download-availability/14896 "2026-04-23T10:25:05Z")
Hello ECMWF team, I have a question about ERA5/ERA5T availability in CDS. I found the note in the CDSAPI issue here: How to get the latest date available for the dataset? · Issue #80 · ecmwf/cdsapi · GitHub , but this … --- ## [TIGGE historical data access for non-Member-state researcher](https://forum.ecmwf.int/t/tigge-historical-data-access-for-non-member-state-researcher/14895)
**Author:** [@elio\_chiu](https://forum.ecmwf.int/u/elio_chiu)\ **Replies:** 0\ **Last updated:** [23 April 2026 10:24 UTC](https://forum.ecmwf.int/t/tigge-historical-data-access-for-non-member-state-researcher/14895 "2026-04-23T10:24:54Z")
Hi, I’m a non-Member-state researcher trying to access TIGGE historical ensemble data (tigge-forecasts on ECDS) for academic weather forecasting research. I have: Registered an ECDS account and obtained a personal a… --- ## [ERAT5 actual download availability](https://forum.ecmwf.int/t/erat5-actual-download-availability/14818)
**Author:** [@Aaron\_Spring](https://forum.ecmwf.int/u/Aaron_Spring)\ **Replies:** 1\ **Last updated:** [13 April 2026 09:47 UTC](https://forum.ecmwf.int/t/erat5-actual-download-availability/14818 "2026-04-13T09:47:32Z")
Hello ECMWF team, I have a question about ERA5/ERA5T availability in CDS. I found the note in the CDSAPI issue here: How to get the latest date available for the dataset? · Issue #80 · ecmwf/cdsapi · GitHub , but this … --- ## [Download CDS data directly to AWS S3 cloud file using fsspec on python](https://forum.ecmwf.int/t/download-cds-data-directly-to-aws-s3-cloud-file-using-fsspec-on-python/980)
**Author:** [@Jim\_Bungener](https://forum.ecmwf.int/u/Jim_Bungener)\ **Replies:** 2\ **Last updated:** [13 April 2026 09:45 UTC](https://forum.ecmwf.int/t/download-cds-data-directly-to-aws-s3-cloud-file-using-fsspec-on-python/980 "2026-04-13T09:45:56Z")
Hello, I need to download a netcdf file from the cds servers directly to an AWS S3 storage location. To do that I would usually have the following code: import fsspec import cdsapi ct = cdsapi.Client(quiet=True) file… --- ## [Brief closure of queues for ERA5 daily requests from Tuesday 17 March, 5PM GMT until end of maintenance system session on Wednesday 18 March](https://forum.ecmwf.int/t/brief-closure-of-queues-for-era5-daily-requests-from-tuesday-17-march-5pm-gmt-until-end-of-maintenance-system-session-on-wednesday-18-march/14787)
**Author:** [@Anabelle](https://forum.ecmwf.int/u/Anabelle)\ **Replies:** 1\ **Last updated:** [18 March 2026 14:10 UTC](https://forum.ecmwf.int/t/brief-closure-of-queues-for-era5-daily-requests-from-tuesday-17-march-5pm-gmt-until-end-of-maintenance-system-session-on-wednesday-18-march/14787 "2026-03-18T14:10:34Z")
To the attention of users of ERA5/ERA5-Land post-processed daily statistics data: Ahead of the planned Data Stores maintenance system session on Wednesday 18 March 2026, it will be necessary to temporally close the queu… --- ## [Optimizing MARS request for historical HRES](https://forum.ecmwf.int/t/optimizing-mars-request-for-historical-hres/14780)
**Author:** [@Manuel\_Davila-Romero](https://forum.ecmwf.int/u/Manuel_Davila-Romero)\ **Replies:** 2\ **Last updated:** [12 March 2026 07:25 UTC](https://forum.ecmwf.int/t/optimizing-mars-request-for-historical-hres/14780 "2026-03-12T07:25:01Z")
Hello, I’m retrieving several years of historical wave forecast data from the operational MARS archive (class=od, type=fc, stream=wave, expver=1). My workflow sends one request per day × run (00/12) × region. Each requ… --- ## [Software upgrade for data extraction of a geographical area from selected ERA5 and Seasonal forecast datasets](https://forum.ecmwf.int/t/software-upgrade-for-data-extraction-of-a-geographical-area-from-selected-era5-and-seasonal-forecast-datasets/14583)
**Author:** [@Anabelle](https://forum.ecmwf.int/u/Anabelle)\ **Replies:** 5\ **Last updated:** [27 February 2026 15:50 UTC](https://forum.ecmwf.int/t/software-upgrade-for-data-extraction-of-a-geographical-area-from-selected-era5-and-seasonal-forecast-datasets/14583 "2026-02-27T15:50:37Z")
On 25th of February 2026 , as part of regular operational software upgrades, the software handling area extraction for regular lat-lon gridded datasets will be updated to a new version to correct a behaviour that caused … --- ## [MarsRuntimeError when downloading specific dates from reanalysis-era5-complete](https://forum.ecmwf.int/t/marsruntimeerror-when-downloading-specific-dates-from-reanalysis-era5-complete/5809)
**Author:** [@Dan\_Casey](https://forum.ecmwf.int/u/Dan_Casey)\ **Replies:** 1\ **Last updated:** [25 February 2026 17:06 UTC](https://forum.ecmwf.int/t/marsruntimeerror-when-downloading-specific-dates-from-reanalysis-era5-complete/5809 "2026-02-25T17:06:41Z")
MarsRuntimeError when downloading specific dates from reanalysis-era5-complete. Are these dates available or is there something that I am missing in my request? The specific missing dates from July until Today (19th Sep… --- ## [Software upgrade for data extraction of a geographical area from selected CAMS global datasets](https://forum.ecmwf.int/t/software-upgrade-for-data-extraction-of-a-geographical-area-from-selected-cams-global-datasets/14605)
**Author:** [@Anabelle](https://forum.ecmwf.int/u/Anabelle)\ **Replies:** 2\ **Last updated:** [25 February 2026 14:14 UTC](https://forum.ecmwf.int/t/software-upgrade-for-data-extraction-of-a-geographical-area-from-selected-cams-global-datasets/14605 "2026-02-25T14:14:19Z")
On 25th of February 2026, as part of regular operational software upgrades, the software handling area extraction for regular lat-lon gridded datasets will be updated to a new version to correct a behaviour that caused a… --- ## [ECMWF MARS retrieve speed(archived operational forecast data)](https://forum.ecmwf.int/t/ecmwf-mars-retrieve-speed-archived-operational-forecast-data/2813)
**Author:** [@Yong\_Luo](https://forum.ecmwf.int/u/Yong_Luo)\ **Replies:** 2\ **Last updated:** [18 February 2026 17:05 UTC](https://forum.ecmwf.int/t/ecmwf-mars-retrieve-speed-archived-operational-forecast-data/2813 "2026-02-18T17:05:46Z")
I am downloading ECMWF MARS archived operational forecast data with python WebAPI. The downloading process is fine but the speed is very slow with pressure level data. When I download Surface data (270M per file) it take… --- ## [Problem downloading from ssp5\_8\_5/gfdl\_esm](https://forum.ecmwf.int/t/problem-downloading-from-ssp5-8-5-gfdl-esm/14706)
**Author:** [@Mo\_Delos](https://forum.ecmwf.int/u/Mo_Delos)\ **Replies:** 0\ **Last updated:** [4 February 2026 22:28 UTC](https://forum.ecmwf.int/t/problem-downloading-from-ssp5-8-5-gfdl-esm/14706 "2026-02-04T22:28:57Z")
6c805f08-3a19-49da-938f-eef9f03aa0ee dataset = “projections-cmip6” temp\_res = “daily” expr= “ssp5\_8\_5” vars =\[“precipitation”\] Returns a small file which given the time period and daily data can’t be correct [Next page](https://forum.ecmwf.int/tag/api/56.md?match_all_tags=true&page=1&tags%5B%5D=api)