Having watched episodes 1-4, it appears there are at least three timelines being shown, and it's quite difficult to decipher between them.
The first time I noticed there were different timelines was Episode 3 "Betrayer Moon". In this, Foltest (a king aged around 40 in Geralt's timeline) appears as a boy of about 10:
The boy's mother refers to him as Foltest and scolds him. The boy and girl are arranged in such a way as to look almost identical to the painting of Foltest and his sister in the castle in which Geralt fights the Striga; another clue.
Episode 4 "Of Banquets, Bastards and Burials" then depicts an interaction between Geralt and Ciri's grandmother. As Ciri is not yet born, this part is at least 15 years behind Ciri's timeline:
Queen Calanthe has organised a banquet for suitors to her daughter, Ciri's mother. At the end it is revealed Pavetta is pregnant with Ciri.
Yet, in the same episode:
Geralt seems to still have only recently met the bard Jaskier/Dandelion, which leads me to think Geralt's timeline has so far been at least 15 years behind Ciri's the whole time. Assuming Ciri is around 15 in her timeline, throughout these 4 episodes.
The timeline for Yennefer seems to jump 30 years ahead in Episode 4, as revealed in Yen's dialogue at the start of the episode.
This corresponds with Foltest now being 40ish (10+30=40), but if Foltest is 40 in Yennefer's and Geralt's timeline, that would mean Ciri's timeline is still 15 years in their future.
Are my deductions accurate? What other clues are there to the various timelines?
A visualisation would be awesome here...