From 05th March 2024, ECMWF will allow Pre-Schedule Delivery for Member States, Co-operating States and users with specific service packages (see page Service Charges: From 01 July 2024 for users with licence starting after 1st July 2024 and page Service Charges: 01 July 2022 - 01 July 2024 for users with licence starting before 1st July 2024).  To request the addition of this feature, please raise a ticket in the ECMWF Support Portal and mark it for the attention of the Data Support Team. 

What is Pre-Schedule Delivery?

ECMWF delivers files according to the dissemination schedule, but the majority of files arrive into the system up to 45 minutes before this and are queued until the schedule. 

With the pre-schedule option, the files will be sent as soon as the files are created and deposited into the ECPDS interface. This means files may arrive between 10-120 minutes before the schedule. 

The timestamp for the creation of files may vary day-by-day and there may be some larger or smaller gaps between steps.  

Files will not be sent until they are available for all users.


Pre-schedule delivery is available to Member States, Co-operating States and Gold Service Pack licence holders. Research users will not be eligible for pre-schedule delivery. 

Datasets eligible for Pre-Schedule Delivery

All datasets within the HRES, ENS, WAVE and ENS-WAVE sets will be eligible for pre-schedule delivery.  Pre-schedule is now available for both push and pull destinations. 

Post-processed products require all steps to be completed prior to sending. 

Where feeds contain a mixture of datasets, those that are not eligible will not be delivered ahead of the schedule.

AIFS data (Set-IX) are not eligible for Pre-Schedule Delivery.

Support for Pre-Schedule Delivery 


Users will be notified of operational issues as per the current arrangement.

Users with pre-schedule delivery should not raise tickets until at least 15 minutes past the Dissemination Schedule and where no operational issues have been reported. 

Before reporting issues, we encourage users to check the status of files in ECPDS and also the ECMWF Service Status.  

Please note that support will not be provided for variability in file arrival times, but users should continue to report perceived traffic slowdowns. 

24/7 support will not include changing the status of feeds from 'normal' to 'pre-schedule'. This will be enabled during office hours Monday-Thursday by Data Support team. 

There are a number of risks to be aware of when using the Pre-schedule Delivery option: 

  1. Files may be corrupt:  if an issue occurs in the production of time steps, we may need to send the file again. With the Dissemination Schedule, we have sufficient time to re-produce a file before it is sent, but this would not be the case for pre-schedule delivery.  This may mean you receive a second copy, or the first copy might be corrupt/missing data.  
  2. Files may arrive non-consecutively:  on occasion the steps may arrive out of order (for example: step 4 may arrive before step 3). Your processing chain should be able to handle this and we will not be able to force consecutive files for pre-schedule delivery. 
  3. Files might not be available before the schedule: in the event of delayed production, files may not be sent before the schedule. 
  4. File priorities can interfere with the delivery: the default priorities of files can interfere with the delivery order, particularly for hourly steps of the 00/12 UTC runs. If your hourly steps have priority=70, these might be delivered after the enfo data streams, which have a default priority of 40. Priorities can be set in the Product Requirements Editor by using priority= 

Enabling Pre-Schedule Delivery

Temporarily, ECMWF Data Support team will enable your pre-schedule delivery option per feed. 

In Q3 2024, we will allow users to request pre-schedule delivery in the Product Requirements Editor. 

Feed options will be updated to include 'normal', 'delay' and 'pre-schedule'. 



Create a support ticket in our Support portal


Please note that support for this service option will be handled only after the dissemination schedule has concluded.