I dreamed about white… Halloween?
It doesn’t have the same ring as a white Christmas, but believe it or not, some parts of the US actually have a good chance of seeing snow on Halloween every year.
Brian Brettschneider, an Alaska-based climatologist, compiled the map below, illustrating the historical probability of a white Halloween.
To qualify for a white Halloween, there must be at least 1 inch of snow on the ground on the morning of October 31 or the snowfall must have accumulated at least 0.1 inches on that date.
This is the same criteria used by the National Weather Service to determine a white Christmas.
This map is based on historical weather data averaged over many years.
Brettschneider noted that snow observations had to go back at least 40 years for locations to be included in his analysis.
The map shown is based on historical weather data averaged over many years. Dr. Brian Brettschneider
In the Lower 48, trick-or-treaters have the highest chance of finding snow on Halloween in the higher elevations of the northern and central Rockies, ranging from a 25% to 50% chance on the highest peaks west of Denver and in parts of Yellowstone National Park in northwestern Wyoming.
However, the probability is lower, 10% to 25%, for most of the Rockies.
Parts of the Washington and Oregon Cascades, the northern Plains, northern Minnesota and the western Upper Peninsula of Michigan also have a 10% to 25% chance of a white Halloween.
There must be at least 1 inch of snow on the ground on the morning of October 31 or the snowfall must have accumulated at least 0.1 inches on that date for it to qualify as a white Halloween. AFP via Getty Images
A snowy Halloween is a rarity for the entire Lower 48, where the probability is usually less than 10%.
Much of the South never records a white Halloween, although the odds are between 1% and 5% as far south as New Mexico and the Texas Panhandle.
If you really want to wear snow boots as part of your costume, head north to Alaska or northern Canada, where there is more than a 50% chance of a white Halloween in some areas.
“Based on climatology, places from Anchorage northward have a greater than 50% probability of a ‘white’ Halloween,” Brettschneider said. “Our friends in the Lower 48 are not so lucky.”
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Source: thtrangdai.edu.vn/en/
