True, there's a timeline on this site, but here's my personal take for the sake of it. Note that it's been converted to the old WC1 system.
For working out dates, two assumptions are made. The first is that Azeroth follows the same seasonal patterns as Earth. Eg. events in Lordaeron's summer would occur in the middle of the year, while events in Durotar's spring would occur late in the year.
The second is that each expansion of WOW takes place over a year (BC lends itself to this theory). The number of patches are subdivided so that they're set throughout the year, unless there is evidence to the contrary.
-13bya (approx.): The universe is created, either through “a catastrophic cosmic explosion” or through “a singular, all-powerful entity.” In the aftermath, a race known as the Titans emerges “to bring order out of chaos.”
-74,420 BCE (approx.): The Titans discover the world that will later be known as Azeroth. However, it is ruled by the Old Gods, who seek to keep the Titans away from their world, harnessing the power of the elements. Disturbed at the Old Gods' penchant for evil, war breaks out between the Titans and Old Gods.
-69,420 BCE (approx.): The Titans defeat the Old Gods and imprison them beneath the planet. They begin shaping the world as they see fit.
-64,420BCE (approx.): The Titans finish creating the world of Azeroth.
War of the AncientsEdit
-13,227BCE: Tyrande Whisperwind is born.
-9,432BCE: Shandris Feathermoon is born.
-9,416BCE: The War of the Ancients begins
-9,415BCE: The War of the Ancients ends.
The Eastern KingdomsEdit
-3,420BCE (approx.): The forest trolls resume their attacks on the high elves.
-2,216BCE (approx.): The human Arathi Tribe realizes that the trolls are too dire a threat to ignore and that a unified humanity is their only chance of survival. They begin a conquest of their neighbouring tribes.
-2,210BCE (approx): The Arathi finish their unification of the human tribes. The nation of Arathor is founded, with its capital being Strom. Soon afterwards the high elves enlist the aid of humanity in their fight against the trolls. As such, the Troll Wars end with human and high elf victory.
-2,116BCE (approx): While the high elves rebuild their kingdom the city state of Dalaran is founded, a haven for humans who wish to learn the ways of magic. However, their reckless use of magic begins to lure demons back into the world. The mages enter a pact with the Convocation of Silvermoon, founding the Order of Tirisfal, which would wage a secret war against the demonic forces of the Burning Legion.
-416BCE: The War of the Shifting Sands occurs.
-385BCE: The city of Stormwind is founded.
-213: Last gnome royalty.
-353: High King Modimus Anvilmar dies and the Bronzebeards, Wildhammers and Dark Irons engage in a civil war over the right to the throne, thus starting the War of the Three Hammers. It ends with Bronzebeard victory.
Eve of ChaosEdit
-388: Muradin Bronzebeard is born.
-510: Cairne Bloodhoof is born.
-520s: Modera is born.
-537: Rise of the Horde (past) begins.
-538: Antonidas is born.
-545: Uther (the) Lightbringer is born.
-551: Kel'Thuzad is born.
-554: Tirion Fordring is born.
-557: Isillien is born.
-570: Khadgar is born.
-571: Medivh's inherent power is unleashed and it takes 100 clerics to keep it at bay. Suddenly, both he and his father collapse; Nielas Aran is dead and Medivh barely alive, existing in a comatose. Medivh is taken to Northshire Abbey.
-Fordring becomes a knight.
-573: Calia Menethil is born.
-577: Llane reaches the Age of Ascension and the title of Prince of Azeroth is bestowed upon him. At the height of the festivities, the doors of the banquet hall blow open and Medivh walks in. He states that he's gained control of his powers and wants to thank the court for their hospitality. He gives Llane an intricately crafted hourglass. Oddly enough, the upper half never emptied and the lower half never filled, despite the fact that the sand was clearly moving. He tells Llane that as long as the top half never emptied, Azeroth would prosper.
-578: Blight descends upon the kingdom; crops fail, children are taken sick and winter and summer were always in their extreme.
-580: Taretha Foxton is born.
-Early 580s: Varian Wrynn is born.
-583: Llane shows to his father how the sand of the hourglass that Medivh gave him is nearly run out. Just as it does so, orcs attack Stormwind. Wrynn sends Llane and Varia to Northshire Abby with an escort of knights. The orcs slaughter their way through the castle until reinforcements arrieve, namely Azeroth's knights. With the orcs unprepared for such warriors, the knights rally Azeroth's foot soldiers and drive the orcs back to the Swamp of Sorrows.
-Barthilas is born.
-584: Llane is pronounced as King of Azeroth. He learns from the orcs how they seem to be encamped in the Swamp of Sorrows to the east. He dedicates himself to ridding the land of these creatures. Numerous skirmishes start erupting, thus starting the First War.
The First WarEdit
-586: Jaina Proudmoore is born.
-Late 586: Lothar is rescued from the Dead Mines.
-Early 587: The Last Guardian occurs.
-The First War ends with orc victory.
The Second WarEdit
-Mid 587: The Second War begins.
-Late 588: The Second War ends.
-589: Construction on Nethergarde begins.
-Mid 589:Day of the Dragon occurs.
-590s: Karandra is born.
-591: Beyond the Dark Portal occurs.
Lord of the ClansEdit
-600: Taelan Fordring is born.
-Anduin Wrynn is born.
-605: Of Blood and Honor occurs.
-Rumors of 'death cults' reach King Terenas.
The Third WarEdit
-609: The Third War begins.
-610: The Third War ends.
-War of the Ancients (present) occurs.
-The Frozen Throne begins.
-611: The Frozen Throne ends.
-Early 612: The Founding of Durotar occurs. The events of the original Warcraft RPG book occur shortly afterwards.
-The Alliance and Horde Compendium is written.
-Mid 612: The Sunwell Trilogy occurs.
-Shadows and Light is written. The short stories in the book occur in this time also.
-613: The WOW RPG book is written.
-Cycle of Hatred occurs.
-More Magic and Mayhem is written.
-Monster Guide is written.
-Dark Factions occurs.
The New AgeEdit
-Concerned that their soldiers are losing morale, the Horde and Alliance make their rank systems more flexible in order to draw in recruits that care little for red tape.
-Mid 614: Onyxia's alias as Lady Katrana Prestor is revealed and she flees Stormwind for her lair in Dustwallow Marsh. Simultaniously, Lord Victor Nefarius, a human who has entered into an alliance with Rend Blackhand at Blackrock Spire, is revealed as the black dragon Nefarian. Despite their misgivings, the Horde and Alliance know that the Black Dragonflight is a threat to both of them. The Horde storms Blackrock Spire, killing Nefarian and Rend and bringing the fel orcs there back in line. Simultaniously, Theramore forces storm Onyxia's lair, killing the black dragon and her unborn young. In the aftermath, both factions enjoy the first Darkmoon Faire, glad that, as far as they can tell, the Black Dragonflight has been eradicated.
-In the ancient city of Zul'Gurub, the Gurubashi trolls succeed in summoning the avatar of Hakkar the Soulflayer. However, they're far from subtle in declaring this and bring down the wrath of the Horde and Alliance on them, Hakkar and his acolytes being defeated as a result. Simultaniously, conflict breaks out in the Arathi Highlands between the League of Arathor and the Defilers.
-Late 614: Green Dragons enter the material world from the Emerald Dream, having been corrupted by something called the Emerald Nightmare. While the night elves are able to defeat them, the exact nature of this malignant force is unknown;not even a vision of Malfurion Stormrage offers much insight. To top it off, the Cenarion Circle reports that something is stirring beyond the Scarab Wall in Silithus.
-The Cenarion Circle's predictions prove correct-the Qiraji are stirring behind the Scarab Wall, eager to avenge their defeat in the War of the Shifting Sands. Banding together, the Horde and Alliance band together, re-opening the gate to the realm. After a titanic battle, the Qiraji are defeated and the Old God C'thun destroyed.
-Winter (as per northern hemisphere): Perhaps timed in order to take advantage of the recent conflict in Silithus, the Scourge suddenly become active in the Plaguelands, the citadel of Naxxramas appearing above the ruins of Stratholme. The attempt is a dismal failure-Scourge forces are easily beaten back by the Forsaken, Scarlet Crusade and Argent Dawn, Naxxramas itself.
-Seeking to capitalize on the power vacuum left by the Scourge's defeat, the Alliance and Horde vie for control for strategic locations in the Plaguelands.
-The Infinite Dragonflight enters the Caverns of Time, seeking to disrupt Azeroth's timeline. Under the guidance of the Bronze Dragonflight however, a band of adventurers are able to preserve history.
The Burning CrusadeEdit
-Early 615: The Burning Crusade is renewed by the Legion, courtesy of Lord Kazzak re-opening the Dark Portal. Although his invasion presses deep, the Horde and Alliance are able to isolate his forces and beat them back. In the aftermath, they turn their attention to Outland.
-Stealing the Light occurs.
-The blood elves join the Horde.
-Rise of the Horde (present) occurs.
-The draenei join the Alliance.
-Lament of the Highborne occurs.
-Stranger in a Strange Land occurs.
-Killing Ground occurs.
-Destiny Awaits! occurs.
-Balancing the Scales occurs.
-The Beast Within occurs.
-The Return occurs.
Wrath of the Lich KingEdit
-Night of the Dragon begins.
-616: Night of the Dragon ends.
-Wrath of the Lich King occurs.