# C3S seasonal forecasts: Updated status of the changes to operational forecast systems (June 2025)

**URL:** <https://forum.ecmwf.int/t/c3s-seasonal-forecasts-updated-status-of-the-changes-to-operational-forecast-systems-june-2025/13511>\
**Category:** C3S - Announcements\
**Tags:** seasonal\_forecast, c3s, cds\
**Created:** [18 June 2025 12:46 UTC](https://forum.ecmwf.int/t/c3s-seasonal-forecasts-updated-status-of-the-changes-to-operational-forecast-systems-june-2025/13511 "2025-06-18T12:46:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Eduardo\_Penabad](https://forum.ecmwf.int/letter_avatar_proxy/v4/letter/e/6a8cbe/32.png) [@Eduardo\_Penabad](https://forum.ecmwf.int/u/Eduardo_Penabad)\
**Post date:** [18 June 2025 12:46 UTC](https://forum.ecmwf.int/t/c3s-seasonal-forecasts-updated-status-of-the-changes-to-operational-forecast-systems-june-2025/13511/1 "2025-06-18T12:46:40Z")

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The switchover to **CMCC SPS4** forecast system has been now **delayed by one month**.

The **release** of the new forecast system, and its integration into the C3S seasonal forecast multi-system was initially planned for July 2025, but it **has been now moved to August 2025**.

**[UPDATE 10/July/2025]**

The initial set of hindcast (re-forecast) data has been released in the C3S seasonal forecast datasets on the [Climate Data Store](https://cds.climate.copernicus.eu/). The start dates available (May and August at the moment) are recorded in the “Hindcast” table of the [Summary of available data](https://confluence.ecmwf.int/display/CKB/Summary+of+available+data) documentation page. The remaining documentation pages for this forecast system will be updated in the week commencing on the 14th of July 2025.