use figures (8 p.m., 4 a.m.) except for noon (12 p.m.) and midnight (12 a.m.)
use a colon to separate hours from minutes
use lowercase, periods, and no space between the letters for a.m. and p.m.
do not include a colon or minutes if the time is exactly on the hour (11 a.m., but 3:30 p.m.)
avoid redundancies such as 10 a.m. in the morning
with time ranges, use the words from and to, not from and an en dash (from 9 a.m. to 2 p.m., not from 9 a.m.–2 p.m.)
with time ranges without the word from, use an en dash with no spaces (Monday–Friday, 2–4 p.m.); if both times are a.m. or p.m., include the a.m. or p.m. with the later time only (8 to 11:30 a.m., 1:30–5 p.m., but 9 a.m.–2 p.m.)
when preparing copy for news releases or Inside UW–Madison, use a hyphen, not an en dash or the word to (from 9 a.m.-2 p.m.)