Variable: display-time-interval
display-time-interval is a customizable variable defined in
time.el.gz.
Value
60
Documentation
Seconds between updates of time in the mode line.
Source Code
;; Defined in /usr/src/emacs/lisp/time.el.gz
(defcustom display-time-interval 60
"Seconds between updates of time in the mode line."
:type 'natnum)