Last updated 10/19/13.
2011: Word of God (or at least of Brian Millikin) confirms that season 4 takes place in mid-late spring of this year. There is a six month gap between October 2010, when the Hunter meteor storm arrives (Thanks for the Memories 3x13), and Duke's resurfacing in Boston (Fallout 4x01), which would place season 4 during April. It's also quite clear that season 4 takes place over a highly condensed period of time, with elapsed time between eps ranging from days to seconds but as yet no more than days.
2010: Most recent surge of Troubles begins, though some Troubles return before this. (Notable on that list are Nathan and Dwight's Troubles. Nathan's starts "a couple of years" before the series begins.)
June or later 2010: Audrey arrives in Haven, at least, judging by the page of the tide charts calendar on Duke's boat in the pilot that's the month. (Which makes current canon late winter/early spring 2011? Approx. Feb or March, which puts us even more squarely in Not Our Universe since here the Orionids show up in October. Unless our timeline is either more compressed than we think, less compressed than we think, or we've spotted a continuity error. We'll ignore the lack of snow in Maine ever because filming schedule, difficulty of filming in snow, and also supernatural little town.)
Six months before Audrey arrives: Piper Taylor's Trouble awakens when her son is killed in a house fire; she stuffs him and brings him back to life.
2008 (?): A "couple years ago," Duke and Nathan go out for drinks on the Cape Rouge; Duke is using Nathan to dodge law enforcement while smuggling something. They end up in a fistfight for "an hour" and Nathan's Trouble returns.
2007 (?): Three years before s3 finale, Jeanine from Reunion has her Trouble awaken. (Reunion 3x12)
1997: Duke wins the Cape Rouge in a poker game on his 21st birthday, which Simon Crocker somehow arranged for 14 years earlier. (Business as Usual 2x12)
199x: Nathan and the Rev's daughter go up to "watch a meteor shower" and have sex instead of going to prom. I'm sure this meteor shower is in NO WAY SIGNIFICANT. (Butterfly 1x02)
1985: Max Hansen goes to prison for killing some family, and supposedly killed the Colorado Kid. (Point of interest: Hansen's disease causes the kind of lack of feeling affliction that both Max Hansen and Nathan Wuornos have.) Garland Wuornos' testimony is crucial to his conviction on at least the CK murder. (Spiral 1x13)
1984 (?): Mrs. Holloway's third-grade class was out camping in a field in May and 12 kids, 2 chaperones died due to Jennie Meers' (sp?) Trouble kicking in and causing fear that killed. Sounds similar to Jackie Clark's Trouble though more overtly/immediately damaging. This is probably an inaccurate date, since the only Mrs. Holloway we know of died while Lucy Ripley was still in town and Simon Crocker is not what we can call a reliable narrator, so call it May of '83 instead. (Sins of the Fathers 2x12)
Note on this year: We're aware that the s3 finale brought up a great deal of contradictory and confusing information surrounding Arla and James Cogan, the barn, and Lucy Ripley's disappearance either on schedule or late, depending on who you listen to. We have every confidence that the showrunners will explain this to us. Someday. As such, until we get Word of God that this is an accidental continuity error, we're going to keep treating it as a plot point.
1983: Previous surge of Troubles. Possibly the majority end with the disappearance of Lucy Ripley but others continue, such as Nathan's (as shown by the recollection of the incident with Duke and the tacks.)
~October 15-22: Lucy Ripley disappears. (Stay 3x02) This is contradicted directly in The Tides That Bind (2x07), when Gwen Glendower/Penny Driscoll tells Audrey that Lucy disappeared "a few days" after the Colorado Kid murder. On the other hand, Lucy only being there "a few months" fits the timeline as established, somewhere between 6-9 months total.
May 28 1983: Colorado Kid is dead. (Opening Credits, all seasons) Sometime between May 3 and this date Vanessa Stanley touches him and learns that the last thing he sees before his death is/was/will be an arm with the Guard tattoo. Lucy Ripley stands with young Duke Crocker (age 8) in the newspaper photo.
May 21 1983: Simon Crocker dies (Born 1946) by drowning at sea, witnessed by Duke Crocker (A Tale of Two Audreys 2x01); sometime shortly before he makes Duke promise to come back to Haven if the Troubles return. (Sins of the Fathers 2x12) According to Driscoll's list this was murder; according to Simon Crocker's spirit Lucy Ripley did it. According to Vince Teagues he and Lucy both participated in the hunt for and murder of Simon Crocker, presumably due to his addiction to Troubled blood having driven him insane and too dangerous to be allowed to live. (Countdown 4x06)
May 3 1983: Colorado Kid is last seen in Nederland CO
February 1983: Nathan Wuornos is 7 years old.
-- Unknown date & location: James Cogan marries Arla [maiden name unknown].
-- Unknown date: the florist from Harmony sells Lucy Ripley daisies (innocence), snapdragons (deception/graciousness), and orchids (beauty).
-- Unknown date: Lucy Ripley gives Duke Crocker (8 at the time) her locket.
-- Unknown date: Lucy Ripley learns to play piano (and specifically learns Your Song, which in our universe was written in 1970; it's therefore unlikely that this is a tune known to prior incarnations)
-- Unknown date: Penny Driscoll "dies", 3 days after running away from him. (Rule of Three!) In reality, she ran off to marry Cole Glendower and faked her death in a car accident afterwards. Her name was changed to Gwen Glendower. Lucy Ripley and Garland Wuornos were in some way involved.
-- Unknown date: Lucy Ripley turns up at Lucy Ripley's doorstep on the run and tells her that someone had died (Cogan?) and that she'd discovered how the Troubles started and how to stop them. The people chasing her wanted to erase her, which apparently they succeeded at doing. New data (3x10 Burned) indicates that these people were members of the Guard, who wanted to force her to walk into the barn and end the Troubles for 27 years. A few months after this, Simon Crocker tracked the original Lucy Ripley down to ask about where AudSarLu was, but wasn't told anything. This directly contradicts with Simon's date of death as given before Lucy's disappearance.
-- Unknown date: Vince Teagues (and Dave? and the Guard? and both?) attempt to force Lucy to become/remember being Sarah, with presumably disastrous results at least to any trusting relationship with Lucy.
1981: Duke & Nathan have known each other since Nathan was 5. (Nathan and Duke are within a year of each other, age-wise; close enough to be classmates at school.)
-- June: The Troubles return two years or more ahead of Lucy, kicking off in Vince Teagues' telling with a Little League pitcher who literally threw his arm out. The Troubles continue progressing over the course of months, leading Vince to request Simon Crocker to allow activation of his Trouble in order for him to murder Vince's father-in-law (wife's name carefully kept unknown at this time though suspected to be Eleanor Carr) and remove the possibility of Vince's wife acquiring the family Trouble. This leads to Vince blaming himself when Simon goes off the rails later on and taking responsibility for Simon's death. (Countdown 4x06)
c. 1960: Last of the Carvers dies off (according to Vince), shortly after (?) the Sarah incarnation's batch of Troubles.
-- Unknown date: Hastings family moves from Kaolin Georgia. Sole survivors of a freakish series of storms that destroys a small town. (Check King tie-in here.) (http://en.wikipedia.org/wiki/Kaolinite) Granddaughter marries, becomes Marian Caldwell. (Pilot 1x01)
-- Unknown date: Dave Teagues is somewhere in his mid-20s, and his worst fear in 2010 is Sarah. (Fear and Loathing 2x02)
-- August 31: James Cogan born to Sarah Vernon, father Nathan Wuornos. Given to June Cogan of Nederland, CO, before Sarah vanishes at the end of this round of Troubles. If conception date of 8/16/55 is accurate, something is playing merry havoc with time in Haven, because longest pregnancy ever. (Sarah 3x09, Magic Hour 3x07/08)
August 16 1955: Sarah Vernon kills grandpa Roy Crocker after he tries to kill her under the impression that she was going to kill him. Simon Crocker is six years old. (Sarah 3x09)
1954: Alexandra Leidner - Born 1925, died 1954 after giving birth to Beattie's mother (Ball and Chain 1x05)
April 8, 1949 Simon Crocker is born. (Sins of the Fathers 2x12)
1786: Regis Glendower, silversmith, made the Crocker box. (Roots 2x05) Commissioned by Fitzwilliam Crocker. (According to Dave Teagues, so may be somewhat questionable in veracity.) (Of note: Fitz is an appellation used to indicate bastardy.)
1700s: Puzzle board created by Tristram Carver which destroys the buildings, possibly along the lines of the girl in Sketchy?
Unknown: Generations ago, the Novelli family Trouble split and went half to Novellis, half to Keegans.
1497: Explorer Sebastian Cabot lands in Haven and writes a journal about his time there, including numerous Mi'kmaq legends about the Troubles and their past. NOTE: This is 19 cycles prior to the current one.
Late 15th/Early 16th Century: The College of William and Mara is founded, i.e. William and Mara arrive in Haven and proceed with their reign of terror.
Founding Families of Haven: At a very rough guess, Teagues, Keegan, Novellis, Carvers, Glendowers, Crockers, Rasmussens. Possibly Wuornos, Hansen, Holloway, Brody.
Unknown, very far past: The darkest time of the Mi'kmaq; a time of great evil when a door was opened that should have remained closed. This may be the beginning of the Troubles, or a noteworthy pause in the cycle, which remains unclear. We do have indications as a result of Cabot's diary that the Troubles have been in the area now known as Haven since time out of mind, however.
Unknown, very far past: Possibly prior to this "darkest time" listed above, possibly congruent with it. We don't know! Isn't it great? William and Audrey's original self, whoever they were calling themselves then, created the Troubles together, according to William, who as we all know is the most reliable narrator ever and totally wouldn't tell Audrey things out of context to screw with her mind.