Comment 1 by torlangballe:

We think this might be the same cause:
I'm in Vietnam, and when I call
zonename, offset := time.Now().In(time.Local()).Zone()
I get a zone-name "ICT"  (Indo-China Time)
When I then call 
time.LoadLocation("ICT")
It returns UTC and the error: "unknown time zone ICT"
I'm on a Mac (go 1.1), so not just a windows problem if it's the same bug,

Comment 2:

I think time.LoadLocation ( http://golang.org/pkg/time/#LoadLocation ) takes zone names
like "Asia/Bangkok" not zone abbreviations like "ICT".
Alex

Comment 3 by diogomfranco:

It does, but that's because, instead of using the system for looking up zones, it
uses a packaged zoneinfo database. The *real* problem is that, given its current
behavior, the time package is unable to parse its own times, such as in
`time.Parse("MST", time.Now().Format("MST"))`.

Comment 4:

Labels changed: added os-windows.

Comment 5:

Remy,
As you described, it fails on linux too:
# cat > main.go
package main
import "fmt"
import "time"
func main() {
        zone, offset := time.Now().In(time.Local).Zone()
        fmt.Println(zone, offset)
        if loc, err := time.LoadLocation(zone); err == nil {
                fmt.Println(loc)
        } else {
                fmt.Println(err)
        }
}
# export TZ='Asia/Kolkata'
# go run main.go
IST 19800
unknown time zone IST
#
Alex

Comment 6:

The zone name returned by Zone can never be used by LoadLocation.
See comment #2.

Status changed to Invalid.

Comment 7 by diogomfranco:

This still leaves the problem that time.Parse can't parse time strings generated by
the time package itself, such as in `time.Parse("MST", time.Now().Format("MST"))`.
Should I open a separate bug for that? Or is this another instance of
https://golang.org/issue/3790 ?

Comment 8:

diogomfranco,
Please, provide example to demonstrate.
Alex

Comment 9 by diogomfranco:

Code: http://play.golang.org/p/CmKvKRSzxi
Output:
Zone: "" -10800
Format:  2006-01-02T15:04:05Z07:00
2013-08-02T13:43:47-03:00
2013-08-02 13:43:47 -0300 -0300
Format:  02 Jan 06 15:04 MST
02 Aug 13 13:43 -0300
parsing time "02 Aug 13 13:43 -0300" as "02 Jan 06 15:04 MST": cannot parse "-0300" as
"MST"
Format:  Monday, 02-Jan-06 15:04:05 MST
Friday, 02-Aug-13 13:43:47 -0300
parsing time "Friday, 02-Aug-13 13:43:47 -0300" as "Monday, 02-Jan-06 15:04:05 MST":
cannot parse "-0300" as "MST"
Format:  Mon, 02 Jan 2006 15:04:05 MST
Fri, 02 Aug 2013 13:43:47 -0300
parsing time "Fri, 02 Aug 2013 13:43:47 -0300" as "Mon, 02 Jan 2006 15:04:05 MST":
cannot parse "-0300" as "MST"
Format:  Mon Jan _2 15:04:05 MST 2006
Fri Aug  2 13:43:47 -0300 2013
parsing time "Fri Aug  2 13:43:47 -0300 2013" as "Mon Jan _2 15:04:05 MST 2006": cannot
parse "-0300 2013" as "MST"
I changed my system language to Japanese and I don't get "ESAST" as the timezone
abbreviation anymore (I presume the abbreviation code just sees a bunch of non-[A-Z]
characters and ignores them all); however "ESAST" was it when windows was in English,
presumably from "E. South America Standard Time"
(http://msdn.microsoft.com/en-us/library/ms912391%28v=winembedded.11%29.aspx
index 065).
Output (system language English):
Zone: "ESAST" -10800
Format:  2006-01-02T15:04:05Z07:00
2013-08-02T13:54:17-03:00
2013-08-02 13:54:17 -0300 ESAST
Format:  02 Jan 06 15:04 MST
02 Aug 13 13:54 ESAST
parsing time "02 Aug 13 13:54 ESAST" as "02 Jan 06 15:04 MST": cannot parse "ESAST" as
"MST"
Format:  Monday, 02-Jan-06 15:04:05 MST
Friday, 02-Aug-13 13:54:17 ESAST
parsing time "Friday, 02-Aug-13 13:54:17 ESAST" as "Monday, 02-Jan-06 15:04:05 MST":
cannot parse "ESAST" as "MST"
Format:  Mon, 02 Jan 2006 15:04:05 MST
Fri, 02 Aug 2013 13:54:17 ESAST
parsing time "Fri, 02 Aug 2013 13:54:17 ESAST" as "Mon, 02 Jan 2006 15:04:05 MST":
cannot parse "ESAST" as "MST"
Format:  Mon Jan _2 15:04:05 MST 2006
Fri Aug  2 13:54:17 ESAST 2013
parsing time "Fri Aug  2 13:54:17 ESAST 2013" as "Mon Jan _2 15:04:05 MST 2006": cannot
parse "ESAST 2013" as "MST"

Comment 10:

diogomfranco,
Like this https://golang.org/issue/5783 ?
Alex

Comment 11 by diogomfranco:

That'd be the case for the Japanese locale one, but I also get the problem in English
(the "ESAST" case).

Comment 12:

Do you? Are you using recent version of Go? If not, try it, please.
Alex