I see a lot of examples in javascript but I cannot find an example to do it in R
Here is the api link: http://api.highcharts.com/highcharts#global
I am tryin
First you have to switch of the useUTC flag to FALSE. Than you can set the timezoneOffset as you wish and save the options back.
global <- getOption("highcharter.global")
global$useUTC <- FALSE
global$timezoneOffset <- -300
options(highcharter.global = global)
For better understanding make sure you take a look at global:
str(global)