So, you're looking back at the calendar and wondering what the heck was going on with the temperature last year today. Honestly, if you were in the United States on January 18, 2025, you were probably either shivering in a weirdly cold basement or watching the news about a massive arctic front that was literally about to rewrite the record books for the Deep South.
It's kinda wild. While most of the planet was actually cooking—January 2025 ended up being the warmest January ever recorded globally—the U.S. was basically an ice box. It was a classic "weather isn't climate" moment. You've got the global average screaming "hot," while your local thermometer in Alabama or Georgia was screaming "where did I put my parka?"
The Great Divide: Global Heat vs. American Ice
On January 18 last year, the world was in the middle of a massive thermal tug-of-war. According to data from the Copernicus Climate Change Service and NOAA, the global average surface temperature for the month was about $1.33°C$ ($2.39°F$) above the 20th-century average.
But here’s the kicker. If you were standing in the Lower 48, you didn't feel that heat. Not even close.
An arctic blast had just plunged into the southeastern United States. While January 18 itself was somewhat "the calm before the storm" in places like Mobile or New Orleans, the air was already turning sharply colder. Meteorologists were frantically issuing Winter Storm Watches for a system that would eventually dump historic snow on the Gulf Coast just 48 hours later.
- Global Status: Hottest January on record.
- U.S. Status: 55th coldest January since 1850.
- The Culprit: A stretched stratospheric polar vortex that dumped all the cold air onto North America while leaving Europe and Russia weirdly mild.
What was the temperature last year today in major cities?
If we look at the specific readings from January 18, 2025, the numbers tell a story of a country on the edge of a deep freeze.
In Boston, the Blue Hill Observatory recorded a high of $41°F$—which is actually about 7 degrees above the normal high. It was a "milder" day for the Northeast before the hammer dropped. But further south, the humidity was rising and the pressure was falling.
In the South, the "mild" afternoon on the 18th was deceptive. In places like Birmingham, temperatures were hovering in the 40s and 50s during the day, but the "Extreme Cold Watch" had already been posted. By the following Monday and Tuesday, those same spots were seeing single digits. It’s that weird pre-storm lull where you know something bad is coming, but the sun is still out.
Why the world was "broken" that day
Climate scientists like James Hansen and Samantha Burgess from Copernicus were basically scratching their heads. Usually, when we have a La Niña event—which we did last year—the world is supposed to cool down a bit. La Niña is the "cool phase" of the Pacific Ocean.
But 2025 didn't care about the rules.
Even with those cool Pacific waters, the rest of the oceans were so record-breakingly hot that they overrode the La Niña effect. On January 18, 2025, we were living through the 18th consecutive month where global temperatures were more than $1.5°C$ above pre-industrial levels. Basically, the planet had a fever that the U.S. "cold snap" couldn't break.
The "Southern Snow" setup
The reason we talk about the temperature last year today so much is because of the freak blizzard that followed.
On January 18, a massive "trough" (basically a giant dip in the jet stream) was pushing south across the central U.S. It was acting like a giant vacuum, pulling moisture up from the Gulf of Mexico and slamming it into that freezing Arctic air.
If you were in Louisiana or the Florida Panhandle on that Saturday, the air felt "heavy." You might have even seen some rain or thunderstorms. Little did people know that by Tuesday, they’d be looking at 10 inches of "fluffy" snow—the kind of snow you usually see in the Rockies, not on a beach in Alabama.
Lessons from the 2025 freeze
What did we actually learn from that day?
- Preparation matters more than the "High": On Jan 18, the high temps weren't scary. It was the rate of the drop that followed. People who didn't wrap their pipes on the 18th were the ones dealing with bursts by the 20th.
- Global vs. Local: Just because your backyard is frozen doesn't mean the planet isn't warming. January 2025 was a textbook example of how a warming Arctic can actually push more cold air down into the U.S. by destabilizing the polar vortex.
- The "Third Warmest" Year: While Jan 2025 started with a record, the year as a whole ended up as the third warmest on record, slightly behind 2024.
How to use this info today
If you’re checking the temperature last year today to plan for this year, remember that January is the most volatile month in the northern hemisphere.
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Next Steps for You:
Check your local "Climate Normal" via the NOAA NCEI website. Compare your current temp to the Jan 18, 2025, data. If you’re seeing a "milder" day today, don't get complacent—the 2025 records show that a 40-degree drop can happen in less than 24 hours when the polar vortex gets wonky. Keep an eye on the "Jet Stream" maps, not just the 7-day forecast.