Oklahomans hoping to sip pumpkin spice lattes in a chilly morning breeze may have to wait a few weeks.
Although the favored fall drink is already here, the cool weather that transitions Oklahoma from summer to winter has yet to show itself.
And according to the latest weather reports, the Arctic’s polar vortex might not dump its cold air this far south until later in October.
When will it get cold? Average first frost dates in Oklahoma
According to nearly 30 years of temperature measurements, the Oklahoma City area usually experiences its first overnight freeze around Oct. 21 each year.
Data collected by the Oklahoma Mesonet also includes historical first-freeze dates for other cities around the state:
Long-term forecast shows warm October
Through the first week of October, temperatures are expected to be above normal for this time of year.
Oklahoma City’s average high temperature on Oct. 1 is 78.5 degrees, according to the National Weather Service in Norman.
The average high temperature continues to fall throughout the month, reaching as low as 73 degrees by Oct. 15. That’s also when the average low temperature dips below 50 for the first time.
What is the polar vortex?
The polar vortex is a swirling mass of frigid air high in the atmosphere, always present near the Arctic.
Its strength and position shift with the seasons, according to the National Weather Service. When the vortex is strong, the coldest air tends to stay near the North Pole. When it weakens or wobbles, pockets of that cold air can sometimes spill south, which can contribute to extreme winter storms or prolonged cold snaps in the U.S.
How much cold actually reaches Oklahoma depends on other atmospheric patterns, like the jet stream and storm systems. Colder air could eventually move into parts of the U.S. as the vortex shifts, but that doesn’t mean immediate blizzards or Arctic outbreaks — it’s simply a sign that the atmosphere is gradually transitioning toward winter.
Over the longer term, forecasters will watch whether the vortex remains stable or weakens later this fall.
Contributing: USATODAY Network Reporter Brandi D. Addison
This article originally appeared on Oklahoman: When will it get cold in Oklahoma? Average first frost dates in state
