Hi there & welcome to the forum ?
It isn't any rule of thumb ... it's to many "it depends".
This from the user manual is what you should start up with & respect ...
Then it's how & where you fly that dictates if you will be successful in a flight if you notices that you have judged the wind speeds wrongly ... if you always fly out into the wind, have a possibility to loose height if needed without risking the RC-AC connection & have plenty of space without obstacles so you can maneuver freely ... Then you rises the odds that you can make it home.
As long as you have a RC-AC connection you always have access to the Sport modes 19m/s & can make headway if the wind is below that, but bear in mind that the battery consumption will be high if fighting a head wind, keep close & turn home in time ... but if you loose connection it's the RTH speed that fights the wind & that is much lower (equals N mode I believe).
Use something that can help you judge the wind speeds on different altitudes ... like the UAV forecast app. It's been pretty believable in my neighborhoods & I have it set to show me winds at 100m. But it's a forecast ... nothing more.
With the correct flying behavior & environment set you can try out winds that's stronger the the max wind resistance stated in the manual, learn when you get wind warnings & how much headroom you have after that.
Then of course ... it's always better to skip flying a too windy day & fly more another instead.