"A Wind Chill Advisory is issued when wind chill index values will
drop to 30 or lower for at least 2 hours for the Rio Grande
Valley and 25 degrees or lower for 2 or more hours for the Rio
Grande plains and northern ranch lands... with winds of 10 mph or
greater."
As someone who lives in one of the coldest places in North America, have to chuckle at the regional "wind chill advisory" as issued for Rio Grand Valley !!!! 30F or lower for at least 2 hours...:B Not to belittle this, wind chill warnings are triggered by vary differing climate regimes, region by region.
As a comparison, wind chill advisories for our area don't even kick in till about -35C (-31F) :E And, in other parts of Quebec, north of St Lawrence River, wind chill warnings don't kick in till -50. We regularly get -30C or much worse here on our mountain for weeks at a time, in December, January and February. When the temps are 25F to 29F and the sun is out, we sit outside in the sun in front of our garage with a glass of wine, taking a tan; the garage is a very effective wind-break :B
Wiki wind chill criteria: "In Canada the warning is issued based on a regions normal climate. Thus in Southern Ontario and Atlantic Canada the warning is issued at -30/-35 and most of Canada it is issued at -45 while in Northern Manitoba and Northern Quebec and the Canadian Arctic the warning is not issued until -50"