On spie.org and SPIE social media properties use the 12-hour clock. For North American events use the 12-hour clock.

 

For European, Australian, and Asian events use the 24-hour clock.

 

Always use hours and minutes. For the 12-hour clock include the time period (AM/PM).

12:00 PM

Never ‘12 PM’ or ‘noon’ or ‘12 noon’ (the first is acceptable on social media)

 

For the 24-hour clock AM/PM is not necessary, but the use of zero in the hours is standard.

08:00

14:30

 

For a time range, always include the hours and minutes for each instance and their time period. Use an en dash WITHOUT spaces on either side for the range. Never ‘to’ or ‘through’ unless it makes sense in a sentence.

11:30 AM–1:30 PM

2:30 PM–5:00 PM

Never

9:30 AM to 12:30 PM

2:00 to 5:00 PM

2–5 PM

But (24-hour clock)

12:00–15:30

08:00–09:30