For the nerds who like knowing these things!

The show takes place in the early 1400s when the Wo pirates were really all over the place causing issues.
Specifically the new emperor mid show is based on the Hongxi emperor (who ruled 1424-25) (and his father before him, Zhu Di who rebelled and led to the irl inspirations for Shen/Lin families being executed), though as people have mentioned in the comments, they've combined a few people IRL.

For context Zhu Di became emperor 1402, and this Instagram video explains the history.

End of the yearish:
Ep 1 (winter): Shen Jialan's mom mentions "I had hoped that after you came of age, you could stay with us for another two years, but by then Jinqi will be over 20", so assuming she's 17 at that point, and he's 21+, they're at least 4 years apart. So when the show starts, likely something like 13/17?

2: We see her get older, the vegetable seller girl get older, and it's the new year. Dad brings her paper, and we transition to six years later but now it's summer, and we get the info that someone's buried the Shen family (so it's probably closer to 7 years total). LX says when she was ten she heard about the painting, so it's likely that at this point she's probably at LEAST 17, if not going on 18 just to make the time passing all fit.

First year we see Seven as LX in full:
Summer
3. Lin Jinqi has returned home, the girls are called to come work for Zhichuan hall.

Fall
4. Fall. LX officially begins working at the Lin family. The plot around ZXT embezzling and such begin.
5. Ji-er makes a splash and is sold off, LX is promoted to 2nd class maid.

Winter
6. LX makes the fur coat, the drama with the seals falling and LX picking it up and realizing the character is for money on the seal.
7. Continued plot around ZXT
8. Party for ZXT's mom at the Zhaos, the reveal of the cheating, divorce, she's gone
9. Aftermath! LX and XL survive because she's the best, Yuchan is back!
10. All the maids are assigned to their new roles, and Du Zheng appears (eugh), and the Chinese New year which is usually between January 21 and February 20.

New Year (so year 2 with LX as an adult) still winter
11. Party time, Du Cuique is plotting (eugh)
12. Aftermath of the whole larkspur flower in the hat plot, the plot about the rotten cotton filled jackets begins

Spring
13. Investigation about the jackets, LX is hurt because she goes undercover
14. Jinqi is arrested, Du Zheng preys on Xiuwan, Xiuru is the only one with a clue, LX and Yuchan go see Marquis Yuan
15. LJQ and Jiugao have an errand to run! Military barrack time, poison plot begins
16. Xiuwan and DZ in a cave, more of the poisoning plot
17. Quarantine begins and LX investigates what the heck is going on
18. DCQ plot fully revealed, we transition into summer

Summer
19. Dai Rong has been arrested, the maids are rewarded and LX asks and gets her family's freedom. Veggie seller says Amaranth is best in the seventh month which is late July to late August! All the drama with Xiuwan and she's put under house arrest.
20. Xiuru will mary Marquis Yuan (if they agree). House hunting! LJQ visits, and then he has to go do Emperor stuff. More time passes, then we get another timestamp that it's been six months later.

Still Summer cards, so I'm working off the assumption that it's the next year and thus year 3 of LX as an adult.
21. Han family drama, bethrothal ceremony for Xiuru and Yuan, LJQ visits again, Zhang Manyi appears (eugh)
22. LX is kidnapped round 1.
23. Deposed prince! Looking for LX! A wild Ji-er appears!
24. LX is out! LX is kidnapped round 2! Most chaotic wedding night for a side character we've seen in a while!
25. Rebellion! LJQ gets Crown Prince to Emperor's bedside before he dies. LX finally gets home. Half a month later, imperial decree ruins EVERYONE's day but LJQ.

Fall
26. Another month has passed and Xiuru comes to save the day for LJQ, sibling scene! Zhangs are executed/self-exit/go to brothel.
27. Wedding no one but LJQ wants to be at, and the smack heard around the Lin Residence!
28. Most awkward meet the in-laws I've seen in a Cdrama for a while, plotting to go to the capital!
29. LX doesn't want to go to the capital! Ope, now she wants to go first thing tomorrow because Ji-er.

Winter
30. They finish traveling to the capital (by boat it seems). Aunt is going to be there for fiveish months to make sure Jinqiao's wedding in May happens appropriately. ZXT meeting (though now she's Dai Furen)
31. LX gets Ji-er back, and LJQ helps Ji-er, her maid, and Zhi-er leave for Quanzhou, 3 more months pass and we're in spring!

Year 4
Spring
32. JG and LX narrate the Tale of the Feathered Immortal (over Xiuwan remembering DZ, Xiulai being abused, Xiuru giving birth to a daughter, and Madam Lin watching her husband with Jinliao's mother). Preparing to get Xiulai out of the house. JQ's wedding is the next day! (So we're in May)
33. Starts in Spring but skips over the wedding entirely and jump to the case so it's probably Juneish, but Xiulai is free!

Winter
34. LJQ's been given a gun! Actual Lanxiang's birthday. Prince Han has an ambush in place for LJQ but LX saves the day by warning him.

I'll come back and update the timeline as we move through the rest of the show. Let me know in the comments if I missed any timestamps from the subtitles/show!

AmelieLucan:

chotoranii:

For the nerds who like knowing these things!

Not just nerds. I often have a hard time figuring how timelines in dramas. I wish someone did this for all the dramas I watch! Thank you.

Honestly if it wasn't for the intro cards before the eps start and them telling us I too would be so confused haha. You're welcome!!