Use only the month and day number (use days of the week, too, for upcoming events within a reasonable period of time); follow AP style for months. Do not use on before a date — even after a proper noun — unless confusion would result from its omission.
For a range of dates, use a hyphen; the hyphen means “through.” Use the month only once if the range of days falls all within the same month, unless the event occurs within the upcoming seven days from the date of publication. If a range of dates is given and the publication date is the first or last day of the range, use the month and day number.
Some illustrations of the above:
The award was presented Aug. 31. Martin presented the award to Waterston Dec. 7. The Bears play Fontbonne University at 6 p.m. today at the Field House. If publishing Sept. 5-11: The Performing Arts Department in Arts & Sciences will perform Oedipus Rex Thurs., Sept. 12 through Sat., Sept. 14 at Edison Theatre. Nominations will be accepted from July 5-Aug. 10. He served as dean from June 15, 1976-May 18, 2001.
See the entries under time, date, place; times; and years.