I have been meaning to download the daily mean of ERA 5 reanalysis data from the Copernicus Climate Data Store, but couldn't find it.

I need the data on pressure levels and currently I am downloading the hourly data on pressure levels, which is very huge, around 2GB for one day.

Do they provide the daily means of ERA 5 data?

It doesn't matter even if it's only accessible through the CDS API.

  • $\begingroup$ Maybe this question helps you? stackoverflow.com/questions/55711188/… $\endgroup$ Commented Dec 13, 2019 at 11:43
  • $\begingroup$ After installing cdstoolbox-remote and modifying the function name from "retrieve_sample_data" to "application", one can directly run @daniel.neumann's code from the command line. (If my reputation were higher, I would post this as a comment.) $\endgroup$
    – chuaxr
    Commented Apr 3, 2020 at 8:57

1 Answer 1



I would suggest using the Toolbox of the Copernicus CDS. Via the Toolbox, you can choose datasets, process them and download the processed results. You have to be registered and logged-in to use the Toolbox.

How to find out how to select the dataset of interest

Use the search of the CDS and go to the bottom of the page. There, you can click/tab Show Toolbox request.

"Show Toolbox request" button in the CDS search

The page is extended and you get some code.

Code for the toolbox to access the selected dataset

Access the Copernicus CDS Toolbox

Now go to the top of the page and click/tab Toolbox or go to this URL: https://cds.climate.copernicus.eu/toolbox-editor

Copernicus CDS Toolbox

You have to be registered to the Copernicus CDS service and be logged-in to be able to use the Toolbox. On the left, you have some example scripts. You can select datasets, process them, create figures, download data and much more. Amongst others, cdo (Climate Data Operators) can be used to process the data. The programming has to be done in Python.

You can select a dataset, calculate daily means and download the processed data via the Toolbox. Combining the cdo example (slightly modified) with the code from the search (described above) should yield some useful code for you.

Example code for the Copernicus CDS Toolbox

Here is an example request, which obtains a part of the data you want. It obtains only data for the year 2007 and for three pressure levels.

import cdstoolbox as ct

@ct.application(title='Retrieve Data')
def retrieve_sample_data():
    data = ct.catalogue.retrieve(
            'product_type': 'reanalysis',
            'pressure_level': [
                '1', '2', '3',
            'year': '2007',
            'month': [
                '01', '02', '03',
                '04', '05', '06',
                '07', '08', '09',
                '10', '11', '12',
            'day': [
                '01', '02', '03',
                '04', '05', '06',
                '07', '08', '09',
                '10', '11', '12',
                '13', '14', '15',
                '16', '17', '18',
                '19', '20', '21',
                '22', '23', '24',
                '25', '26', '27',
                '28', '29', '30',
            'time': [
                '00:00', '01:00', '02:00',
                '03:00', '04:00', '05:00',
                '06:00', '07:00', '08:00',
                '09:00', '10:00', '11:00',
                '12:00', '13:00', '14:00',
                '15:00', '16:00', '17:00',
                '18:00', '19:00', '20:00',
                '21:00', '22:00', '23:00',

    data_daily = ct.climate.daily_mean(data)

    return data_daily
  • $\begingroup$ There's a module installable in a local system for the CDS toolbox called cdstoolbox-remote, are you familiar with it? $\endgroup$
    – RogUE
    Commented Dec 16, 2019 at 9:28
  • $\begingroup$ No, sorry. I did not use it. $\endgroup$ Commented Dec 18, 2019 at 8:51

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