Ignore the clock. If it is before lunch, say good morning. If it is after lunch, but before whatever kind of break happens between 4 and 7, say good afternoon. After that say good evening. Only say good night at the end if you said good evening at the beginning. Thanks to all for your insightful answers!!
If you like a big send-off, try one of these: Best, (short for "best regards" and good for formal and informal e-mails) Sincerely, (formal) See you soon, (informal) Hope to hear from you, (somewhere between formal and informal) Regards, (formal and a little old-fashioned) All of the preceding closings contain commas.
Good night in many languages. Jump to phrases. How to wish someone a good night in numerous languages. These are phrases you use when parting from others at night. Key to abbreviations: inf = informal, frm = formal, sg = said to one person, pl = said to more than one person. Click on any of the phrases that are links to hear them spoken.