Indicate the format of your date/time string

You can indicate the format of your date/time string in the following way:

Format character Description Example returned values
Day d Day of the month, 2 digits with leading zeros 01 to 31
D A textual representation of a day, three letters Mon through Sun
j Day of the month without leading zeros 1 to 31
l (lowercase ‘L’) A full textual representation of the day of the week Sunday through Saturday
N ISO-8601 numeric representation of the day of the week 1 (for Monday) through 7 (for Sunday)
S English ordinal suffix for the day of the month, 2 characters st, nd, rd or th
w Numeric representation of the day of the week 0 (for Sunday) through 6 (for Saturday)
z The day of the year (starting from 0) 0 through 365
Week W ISO-8601 week number of year, weeks starting on Monday Example: 42 (the 42nd week in the year)
Month F A full textual representation of a month, such as January or March January through December
m Numeric representation of a month, with leading zeros 01 through 12
M A short textual representation of a month, three letters Jan through Dec
n Numeric representation of a month, without leading zeros 1 through 12
t Number of days in the given month 28 through 31
Year L Whether it’s a leap year 1 if it is a leap year, 0 otherwise.
o ISO-8601 week-numbering year. This has the same value as
Y, except that if the ISO week number
(W) belongs to the previous or next year, that year
is used instead.
Examples: 1999 or 2003
Y A full numeric representation of a year, 4 digits Examples: 1999 or 2003
y A two digit representation of a year Examples: 99 or 03
Time a Lowercase Ante meridiem and Post meridiem am or pm
A Uppercase Ante meridiem and Post meridiem AM or PM
B Swatch Internet time 000 through 999
g 12-hour format of an hour without leading zeros 1 through 12
G 24-hour format of an hour without leading zeros 0 through 23
h 12-hour format of an hour with leading zeros 01 through 12
H 24-hour format of an hour with leading zeros 00 through 23
i Minutes with leading zeros 00 to 59
s Seconds, with leading zeros 00 through 59
u Microseconds. Example: 654321
Timezone e Timezone identifier Examples: UTC, GMT, Atlantic/Azores
I (capital i) Whether or not the date is in daylight saving time 1 if Daylight Saving Time, 0 otherwise.
O Difference to Greenwich time (GMT) in hours Example: +0200
P Difference to Greenwich time (GMT) with colon between hours and minutes Example: +02:00
T Timezone abbreviation Examples: EST, MDT …
Z Timezone offset in seconds. The offset for timezones west of UTC is always
negative, and for those east of UTC is always positive.
-43200 through 50400
Full Date/Time c ISO 8601 date 2004-02-12T15:19:21+00:00
r RFC 2822 formatted date Example: Thu, 21 Dec 2000 16:01:07 +0200
U Seconds since the Unix Epoch (January 1 1970 00:00:00 GMT) 1497957607

Here you can see some examples of a date/time format and how is represented:

F j, Y, g:ia                   // May 16, 2017, 4:29pm
m-d-y                          // 05-16-17
m/d/y                          // 05/16/17
j, n, Y                        // 16, 5, 2017
Ymd                            // 20170516
jS \d\a\y                      // 16th day
D M j Y G:i:s                  // Tue May 16 2017 16:29:09
H:i:s                          // 16:29:09
Y-m-d H:i:s                    // 2017-05-16 16:29:09 (MySQL DATETIME format)