If you travel, you will probably have the problem that the time on your laptop is still the home time. On mobile phones, the time will automagically be retrieved from the mobile network time, but if you do not have a mobile connection on your laptop, this is quite hard. But there is a trick you can do, which requires the use of geoip-bin.

Just lookup your public wifi IP and compare it to the geoip database:

TZ=$(geoiplookup $(curl -s ipconfig.sh) | cut -d " " -f 4 | tr -d ',') date

With a little bit of scripting, you can put this into a nice script, which will refresh the cache of the local timezone every hour.

# this script tries to get the local time by checking the public wifi IP

if ! [ -f ~/.cache/localtime.cache ] || [ $(($(date +%s) - $(stat --printf '%Y' ~/.cache/localtime.cache))) -gt 3600 ] ; then
    geoiplookup $(curl -s ipconfig.sh) | cut -d " " -f 4 | tr -d ',' > ~/.cache/localtime.cache
    if [ $? -ne 0 ]; then
        exit 1

if [ -z "$1" ]; then

if [ -f ~/.cache/localtime.cache ]; then
    TZ=$(cat ~/.cache/localtime.cache) date +"$FMT"
    date +"$FMT"

Later I found out, that this script does only work, if the country you are in, is listed as an own timezone in /usr/share/zoneinfo. It is the case for GB but for example not for AT. There are some conversion lists, but you will obviously get problems when you are in the US or Russia, as those countries span multiple timezones. So yeah, this script kind of work in some cases only. But I hope you get the point and can adjust it to your needs!