A Chronology of My Little Pony: Friendship is Magic · 6:44pm Apr 30th, 2015
Greetings, my Brony brethren!
As promised, I have produced a chronology of events on My Little Pony: Friendship is Magic based on the information we have so far. I will very likely be editing this chronology as new episodes and comics come. (Yes, I have included some of the comics in this chronology as well as the Equestria Girls movies.) I was considering doing a whole blog explaining my reasoning for why I ordered the series in this way, but it will have to wait. Feel free to point out if there were details that I may have neglected when it came to the order of some episodes.
Summer- 1st Year
Season 1
(1-2) Friendship is Magic
(3) The Ticket Master
(4) Applebuck Season
(5) Griffon the Brush Off
(6) Boast Busters
(7) Dragonshy
(8) Look Before You Sleep
(9) Bridle Gossip
(10) Swarm of the Century
(12) Call of the Cutie
Fall- 1st Year
(13) Fall Weather Friends
(30) Luna Eclipsed
Winter- 1st Year
(11) Winter Wrap Up
Spring- 1st Year
(14) Suited for Success
(15) Feeling Pinkie Keen
(16) Sonic Rainboom
(17) Stare Master
(18) The Show Stoppers
(19) A Dog and Pony Show
(20) Green Isn't Your Color
(21) Over a Barrel
(22) A Bird in the Hoof
(23) The Cutie Mark Chronicles
(24) Owl's Well That Ends Well
(25) Party of One
(26) The Best Night Ever
Season 2
(27-28) The Return of Harmony
(29) Lesson Zero
(32) The Cutie Pox
(34) The Mysterious Mare Do Well
(36) Secret of My Excess
(38) Family Appreciation Day
(43) Hearts and Hooves Day
Summer- 2nd Year
(31) Sisterhooves Social
(35) Sweet and Elite
(39) Baby Cakes
(40) The Last Roundup
(41) Super Speedy Cider Squeezy 6000
(42) Read It and Weep
(47) Dragon Quest
(44) A Friend in Deed
(45) Putting your hoof down
(46) It's About Time
(48) Hurricane Fluttershy
(50) MMMystery on the Friendship Express
(51-52) A Canterlot Wedding
Fall- 2nd Year
(49) Ponyville Confidential
Comic- Return of Queen Chrysalis arc
Winter- 2nd Year
(37) Hearth's Warming Eve
Spring- 2nd Year
Season 3
(53-54) The Crystal Empire
Summer- 3rd Year
(56) One Bad Apple
(57) Magic Duel
(60) Apple Family Reunion
Comic- Nightmare Rarity Arc
Comic- Neigh Anything
Comic- Zen and the Art of the Gazebo Repair
Fall- 3rd Year
Winter- 3rd Year
Comic- Applejack Micro-Series
Spring- 3rd Year
(33) May the Best Pet Win!
(55) Too Many Pinkie Pies
(58) Sleepless in Ponyville
(59) Wonderbolts Academy
(61) Spike at Your Service
(62) Keep Calm and Flutter On
(63-64) Just for Sidekicks/Games Ponies Play
(65) Magical Mystery Cure
Equestria Girls
Comic- Reflections arc
Summer- 4th Year
Season 4
(66-67) Princess Twilight Sparkle
(68) Castle Mane-ia
(69) Daring Don't
(70) Flight to the Finish
(71) Power Ponies
(72) Bats!
(73) Rarity Takes Manehattan
(74) Pinkie Apple Pie
(75) Rainbow Falls
(76) Three's a Crowd
(77) Pinkie Pride
(78) Simple Ways
(79) Filli Vanilli
(80) Twilight Time
(81) It Ain't Easy Being Breezies
(82) Somepony to Watch Over Me
(83) Maud Pie
(84) For Whom the Sweetie Belle Toils
(85) Leap of Faith
(86) Testing, Testing, 1, 2, 3
(87) Trade Ya
(88) Inspiration Manifestation
(89) Equestria Games
(90-91) Twilight's Kingdom
Equestria Girls: Rainbow Rocks
Season 5
(92-93) The Cutie Map
(94) Castle Sweet Castle
(95) Bloom & Gloom
(97) Appleloosa's Most Wanted
(99) The Lost Treasure of Griffonstone
(100) Slice of Life
(101) Princess Spike
(102) Party Pooped
(103) Amending Fences
(104) Do Princesses Dream of Magic Sheep
(105) Canterlot Boutique
(107-108) Made in Manehattan/Brotherhooves Social
"September"
(109) Crusaders of the Lost Mark
(110) The One Where Pinkie Pie Knows
Fall-4th Year
(112) Scare Master
(96) Tanks for the Memories
Winter- 4th Year
(111) Hearthbreakers
Spring- 4th Year
(98) Make New Friends But Keep Discord
(106) Rarity Investigates!
(113) What About Discord?
(114) The Hooffields and McColts
(115) The Mane Attraction
(116-117) The Cutie Remark/Equestria Girls: Friendship Games
Season 6
Summer- 5th Year
(118-119) The Crystalling
(120) The Gift of Maud Pie
(121) On Your Marks
(122) Gauntlet of Fire
(123) No Second Prances
(124) Newbie Dash
(127) Applejack's "Day" Off
(128) Flutter Brutter
Fall- 5th Year
(126) The Saddle Row Review
Winter- 5th Year
(125) A Hearth Warming's Tail
Spring- 5th Year
(129) Spice Up Your Life
(130) Stranger Than Fan Fiction
(131) The Cart Before the Ponies
(132) 28 Pranks Later
(133) The Times They Are a Changeling
(134) Dungeons and Discords
(135) Buckball Season
(136) The Fault in Our Cutie Marks
(137) Viva Las Pegasus
(138) Every Little Thing She Does
(139) P.P.O.V. (Pony Point of View)
(140) Where the Apple Lies
(141) Top Bolt
God bless you all. God bless America. And God bless Equestria.
I very much like this chronology you've set up.
While not official, it at least helps my mind wrap around the fact of Tanks for the Memories showing Rainbow Dash's first winter with Tank. Thank you for this. 
3035911 You're welcome!
For now at least.
Muahahaha! Mine is an evil laugh!
Can't say I disagree with anything here. Very well thought-out.
3172677 It's what I do
... When I'm feeling incredibly anal. 
I think that Seasons 3, 4, and the first half of 5 are set in the same year.
Luna Eclipsed is more likely set just two months before Hearts Warming Eve.
A Canterlot Wedding parts 1 and 2, along with most of the other episodes in the second half of season two are most likely set in spring after Hearths Warming Eve, so to with Sweet and Elite, since it mentions the Grand Galloping Gala.
All the season 3 episodes are likely set in late spring after A Canterlot Wedding parts 1 and 2.
The episodes Filli Vanilli, Twilight Time, and Flight to the finish, along with Rainbow Falls, Equestria Games and Twilight’s Kingdom are likely set in late summer since those first two or three episodes are school days.
All the season 7 episodes are likely set in late spring and early to late summer after the events of To Where and Back Again parts 1 and 2.
The movie is likely set in late summer.
The first half of season 8 probably is set in fall and winter, and the second half in spring.
I think that the Best Gift Ever and the shorts are set just two months after a few episodes in the first half of season 9.
The series began set in summer and it ended in a summer setting.
I'm not one to be picky, but I have spotted a discrepancy. Nothing major, but The Return of Queen Chrysalis must take place after May the Best Pet Win. Tank appears in the comic, yet you have it placed after the episode.
I mean, it doesn't really matter, anyway, with how out of date it is (2015, yikes!) but I still felt it was worth mentioning for anyone else who stumbles across this.