Tried to leave this as a Conversation but for some reason it wouldn't let me.
The timeline book confirms Civil War as Spring 2016, so the latest it should be is Mid-June.
- May 3rd, 2016- Lagos/Tony at MIT (matching the real world date of the WHIH breaking news tweet)
- June 12th, 2016- Ross announces the Accords/Peggy's death (Lagos was "last month")
- June 15th, 2016- Peggy's Funeral/UN Bombing (Ross mentions the Accords would be ratified in 3 days and it makes sense for Peggy's funeral to be a few days after her death)
- June 16th, 2016- Bucky's Capture, Zemo activates him which allows him to escape, Ross gives Tony 36 hours to bring Bucky in, Tony recruits Peter, Clint recruits Wanda and Scott
- June 17th, 2016- Airport Battle/Siberia. Homecoming mentions that Tony took Peter for the weekend and Peter's extended video journal shows the day after the battle as being a Saturday
- June 18th, 2016- Zemo is locked away, Natasha evades Ross's men while hiding out, and Yelena is broken out of her mind control
- June 19th, 2016- Tony returns Peter back to Queens, Natasha is in Norway and is given a package by Mason from the Budapest safe house from Yelena, that night she is attacked by Taskmaster, Peter lies to May about his injuries
- June 20th, 2016- Natasha arrives in Budapest and discovers Yelena, they are attacked by Black Widow agents and Taskmaster, the two rebond and Natasha figures out she can get Dreykov's location from Alexei and decides to break him out (This is the first official day of Summer which fits with the timeline book saying the movie is Spring-Summer 2016).
- June 21st, 2016- Natasha and Yelena help break Alexei out, they go to Melina's where that night they're ambushed by the Red Room
- June 22nd, 2016- Destruction of the Red Room, T'Challa saves Nakia (the news report says the UN bombing was a week ago, this would exactly be a week)
- June 23rd, 2016- T'Challa returns to Wakanda with Nakia and Okoye and reunites with Ramonda and Shuri, in London Killmonger and Klaue steal vibranium from a museum, T'Challa faces M'Baku and is officially made king, he then visits the Astral Plane and sees his father.
- June 24th, 2016- T'Challa begins his first day as king and is told that Klaue has shown up on their radar, stealing a Wakandan weapon "yesterday" and that he plans to sell to an American buyer in South Korea "tomorrow night". T'Challa visits Shuri's lab as she shares her new inventions.
- June 25th, 2016- Klaue is arrested in South Korea.
- June 26th, 2016- The next morning, Everett Ross interrogates Klaue, Killmonger helps Klaue escape, an injured Ross is taken back to Wakanda, and Killmonger kills Klaue and his girlfriend.
- June 27th, 2016- Killmonger brings Klaue's body to Wakanda, he later meets with the Tribal Council claiming his right to the throne, T'Challa and Killmonger fight, Zuri is killed, T'Challa is presumed dead, Killmonger takes the Heart Shaped Herb burning the rest.
- June 28th, 2016- Killmonger takes his seat on the throne and explains his plan to give Vibranium weapons so oppressed African descendants can fight against those in power, T'Challa is healed after his body is recovered from the Jabari tribe and asks for their help stopping Killmonger, Killmonger begins his plans but after battle is defeated and dies while watching the sunset.
- June 29th, 2016- T'Challa reclaims his seat on the throne and convinces Nakia to stay in Wakanda.
- July 2016- Natasha helps Steve break out The Raft prisoners/Tony is notified about the escape (Black Widow says this event is 2 weeks from the rest of the movie)
Some of the credit scenes set later are left out but I'll let you decide what you feel is best with them.