If the days of the month in your file were all two digits (padded with 0 if necessary), then this example in the info page of GNU sort can help:
* Sort a set of log files, primarily by IPv4 address and secondarily
by time stamp. If two lines' primary and secondary keys are
identical, output the lines in the same order that they were
input. The log files contain lines that look like this:
4.150.156.3 - - [01/Apr/2004:06:31:51 +0000] message 1
211.24.3.231 - - [24/Apr/2004:20:17:39 +0000] message 2
Fields are separated by exactly one space. Sort IPv4 addresses
lexicographically, e.g., 212.61.52.2 sorts before 212.129.233.201
because 61 is less than 129.
sort -s -t ' ' -k 4.9n -k 4.5M -k 4.2n -k 4.14,4.21 file*.log |
sort -s -t '.' -k 1,1n -k 2,2n -k 3,3n -k 4,4n