From the blog…
Season 25 will begin on December 10, at 5PM (PST/CEST/KST)
Europe hasn’t been observing Daylight Savings since the 31st October, and is now in CET (Central European Time) not CEST (Central European Summer Time).
Please correct the blog, and ensure that the season actually starts at 17:00 CET (16:00 UTC) not 17:00 CEST (15:00 UTC) on the EU server.