In a series like Agents Of SHIELD, in which the timeline isn't always strictly laid out and birthdays aren't celebrated on screen, it can be difficult to discern dates of birth and zodiac signs for characters. There are only a handful of characters that do have their dates of birth revealed in the show's canon.
In some cases, the character's birth dates are revealed when a file is flashed on screen, on a SHIELD ID badge, or even thanks to a well-placed origin story. Thanks to those birth dates, fans can figure out the in-universe zodiac signs of several characters, but not every character fits the characteristics of their sign.
Phil Coulson: Cancer
Born on July 8 according to his SHIELD ID, Phil Coulson is a Cancer right in the middle of the sign's reign. Cancers are in touch with their emotions, incredibly protective, and are very imaginative. All of those traits are in line with Coulson, so he's one of the instances of the sign being a good fit in the show.
Coulson is someone who thinks outside of the box, like having those SHIELD has pursued join his team, and treats his team like more than just his employees. His team becomes his family.
Bobbi Morse: Gemini
Bobbi's birthday isn't actually revealed in the series. Neither is her zodiac sign. Instead, she references herself as a Gemini in her solo comic book series, Mockingbird. The bit of trivia comes to fans in the third issue.
Geminis are versatile. They're able to adapt to changing situations with seeming ease, though underneath their calm exterior, they can be incredibly anxious. That sounds like the perfect zodiac sign for one of the best undercover agents SHIELD has ever had.
Mike Peterson: Virgo
Thanks to Skye (AKA Daisy Johnson) swiping his ID in the pilot episode of the series, fans know Deathlok's birthday is August 28. That puts him at the beginning of Virgo season.
Virgos are planners. They love to be organized and prepared. Mike tries very hard to be a planner. He wants what's best for his son, and sees a future for him when he joins the CENTIPEDE program. Unfortunately, Mike doesn't have all of the information at hand there, and he spends a lot of his time off screen trying to make up for that decision.
Lincoln Campbell: Aries
Lincoln's birthday comes to the audience in his final episode of the show, the season three finale. Born on April 17, he's an Aries baby.
Aries are typically very heroic, but that's more because they impulsively leap into action than anything else. Lincoln is one of the characters who doesn't quite fit with the stereotypes associated with his sign. He's more likely to want a well-thought out plan than most Aries are.
Aida: Sagittarius
Aida, who eventually becomes Ophelia, or Madame Hydra, doesn't have an exact birth date revealed in the series. Instead, the audience knows that her life begins just under six months after Lincoln's death in June 2016. That makes her "birthday" when Holden Radcliffe first speaks to her in mid-December, and Aida a likely Sagittarius.
Sagittarius is the perfect sign for her. With a love for learning and some serious wanderlust, Sagittarius always want to know and see more. Aida's obsession with human emotion causes her to want to be as human as she can. She zeroes in on Leo Fitz in order to achieve that in a pretty creepy way.
Daniel Sousa: Cancer
Daniel Sousa joins the characters on their time traveling missions in the final season of the series, but it certainly feels like he's been a part of the team for longer. He's a perfect fit for the team from the moment Daisy peruses his file. With a July 22 birthday, Sousa is a Cancer on the cusp of becoming a Leo.
That might be why he and Coulson get along so well. They both connect to the team - specifically Daisy - very quickly. Sousa also comes up with some creative solutions, like turning chronicoms into bombs, in hopes of solving the team's problems.
Grant Ward: Capricorn
Grant Ward, as revealed in his original SHIELD ID, shares his birthday with the actor who plays him. Since Brett Dalton celebrates on January 7, so does the villainous Ward, making them both Capricorns.
Capricorns are ambitious, hard working, and duty driven. While Ward does eventually start his own version of Hydra, he's only with Hydra to begin with because he feels like he owes John Garrett everything. That's ambition and duty right there. Grant Ward is also constantly training and observing, treating every moment like an exercise in spy craft, proving how hard he works.
Jemma Simmons: Virgo
Like Ward, Jemma Simmons shares her fictional birthday with the actress who plays her, Elizabeth Henstridge. Born on September 11, they're both Virgos.
A love for planning and the structure provided by rules? Check. A need to be organized? Check. Jemma is the stereotypical Virgo. She refuses to break the rule because they "make her feel nice" early in the series. Fitz makes sure no one touches her work space when she disappears between seasons two and three because he knows she likes things just so. Jemma even goes back in time with a plan that she doesn't entirely remember thanks to a piece of technology embedded in her brain in the final season.
Leo Fitz: Leo
Maybe the writers and producers were having a little fun when they give Fitz a star sign to match his name. With a birthday of August 19 on his SHIELD ID, Leo Fitz is born under the sign of Leo.
Leos love to be the person everyone else pays attention to, and for much of the series, Fitz gets that attention thanks to his intelligence and scientific know-how. Leos also tend to understand their strengths extremely well - and make sure everyone else knows them. Fitz has no problem reminding everyone just how smart he is.
Daisy Johnson: Cancer
Thanks to a tumultuous childhood and a SHIELD agent hiding her from her birth parents, for a long time, Daisy Johnson doesn't even know her own birthday. It's not until she meets her parents in the second season that she learns she was born on July 2, making her a Cancer.
She has her sign in common with her mentor Coulson and love interest Sousa. It's no wonder that Coulson found her incredibly empathic early in the series. She finds common ground and cares deeply for people, just as they do, causing her to reach out and try to help before she tries fighting. Her experiences with characters like Hannah in the season one episode "Repairs" and Kora in the final season, it's easy to see just how much Daisy cares.