Import date-time at a specified timezone, disregard Daylight Savings Time

Question

I have time series data obtained from a data logger that was set to one time zone without daylight savings (NZST or UTC+12:00), and the data spans a few years. Data loggers

Answer 1

You can use tz="Etc/GMT+12":

as.POSIXct(ts_str, format="%d/%m/%Y %H:%M", tz="Etc/GMT+12")
[1] "2008-09-28 01:00:00 GMT+12" "2008-09-28 02:00:00 GMT+12"
[3] "2008-09-28 03:00:00 GMT+12"

For a full list of available timezones use,

dir(file.path(R.home("share"),"zoneinfo"), recursive=TRUE)

There are a couple of of .tab files in there which aren't timezones but hold some information, but my regex-fu isn't good enough to be able to exclude them with the pattern argument to dir.

Answer 2

If just add 12*60*60 to that UTC derived vector, you will have local "standard" time.