You wouldn’t write it out as “twenty fif.th”, so you wouldn’t put the period in the middle of the word when using superscripts either.

If you are using a style guide, check to see if you’re supposed to be using superscripts with dates anyways. APA style, for example, says to make it regular case, which would be:

• on the 25th.

If you’re not using a style guide, consider writing it like this.

You wouldn’t write it out as “twenty fif.th”, so you wouldn’t put the period in the middle of the word when using superscripts either.

If you are using a style guide, check to see if dates should have superscripts or not. APA style, for example, says to make it regular case, which would be:

• on the 25th.

If you’re not using a style guide, consider writing it like this.