The output of `date "+%m"` in july is "07". It is possible to remove the leading zero by using the following syntax `date "+%-m"` which will output "7".
I haven't been able to find this in date(1), strftime(3), strptime(3).
I found it by looking gnu date man page and trying it on FreeBSD.
This is documented in strftime(3) which is referenced by date(1):
| %-* GNU libc extension. Do not do any padding when performing
| numerical outputs.
(In reply to Fabian Keil from comment #1)
Sorry for the fuss.