Represent dates and times following the Chicago Manual of Style with some modification.
For times on the hour, do not include the minutes, for example as “10 a.m.”. Removing the “:00” reduces noise for assistive technology.
Include the minutes for any times that are not on the hour, such as “1:30 p.m.”. Use “noon” and “midnight” instead of their more confusing numerical counterparts “12 p.m.” and “12 a.m.”.
Use the word "to" between time ranges rather than a dash. Assistive tech often disregards this type of punctuation, and in this instance the word version “to” does not take up much more space but can vastly improve understanding (e.g. 10 a.m. to 11 a.m. instead of 10 a.m.-11 a.m.).
Libraries are closed for .
The event starts at
<time>10 a.m. to midnight</time>
<p>Libraries are closed for <time datetime="2019-01-21">Martin Luther King Day</time>.</p>
<p>The event starts at <time datetime="13:00">1 p.m.</time></p>