Act III. But that is only because "climax" is defined as "Act III of a Shakespearean play" in the Freytag Pyramid theory of the structure of a Shakespeare play.
Seems to be Act 3.
For some people the word "climax" has a technical sense when discussing a play. This might cause them to identify the climax with act 3 of any Shakespearean play. In a non-technical sense, the climax of the play comes when Othello smothers Desdemona. He had a chance up to that point but none after.
Act IV
Hamlet, Act 3 Scene 1
This varies depending on the play, but for most it would be when the main character has a sudden realisation moment, an Epiphany or change of heart, which either alters the plays main initial intent or brings it to a different end
Seems to be Act 3.
For some people the word "climax" has a technical sense when discussing a play. This might cause them to identify the climax with act 3 of any Shakespearean play. In a non-technical sense, the climax of the play comes when Othello smothers Desdemona. He had a chance up to that point but none after.
Act IV
If you are talking about Freytag's pyramid, the "climax" is always Act 3. In terms of dramatic tension, this reaches its peak when Othello is about to kill Desdemona.
The quotation "To be or not to be" is from Act III, Scene I of Shakespeare's Hamlet.
Hamlet, Act 3 Scene 1
The first act was the introduction, where you would meet all the characters, the second is where complications arise, the third is the rising action where things leading up to the climax happen, the forth is the climax or most suspenseful point, then falling action where everything is coming to an end, then the catastrophe which usually results in the death of Shakespeare's hero.
The acts in a Shakespearean play serve to structure the plot and provide a sense of progression. Each act typically represents a major development in the story, building tension and leading towards the climax. Acts help to organize the play into manageable segments for both the performers and the audience.
The Comedy of Errors (Act III, Scene ii).
As You Like It, Act 2 Scene 7
This varies depending on the play, but for most it would be when the main character has a sudden realisation moment, an Epiphany or change of heart, which either alters the plays main initial intent or brings it to a different end
Act III, Scene 1 is the climax because there is no turning back for Romeo after he kills Tybalt.