Honestly, walking outside in Phoenix today doesn't feel like mid-January. It feels more like the tail end of April. While much of the country is bracing for a "much below normal" cold snap later this month, Arizona is currently trapped in a stubborn ridge of high pressure.
Arizona heat advisory news isn't usually the headline at the start of the year, but the 2026 winter season is rewriting the rulebook. We aren't seeing 115-degree warnings—thankfully—but the National Weather Service (NWS) in Phoenix is tracking temperatures 5 to 10 degrees above historical averages. On January 18, 2026, many lower desert areas are hitting the mid-to-upper 70s. Some spots like Yuma are even flirting with 80°F.
It’s a weird time. You've got people hiking Camelback Mountain in tank tops when they should be in light jackets.
The Omega Block and Your Weekend Plans
Why is it so warm? Meteorologists at the NWS Phoenix office are pointing to something called an "Omega block." Basically, the jet stream is shaped like the Greek letter $\Omega$, locking high pressure over the Southwest. This acts like a lid on a pot, keeping the cool, rainy storms from the Pacific pushed far to our north.
Here’s the breakdown of what we’re seeing right now:
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- Daytime Highs: 73°F to 78°F through the early part of this week.
- Humidity: Dropping into the 15% range. It's bone-dry out there.
- Winds: Mostly light, though the Lower Colorado River Valley is seeing some 20 mph gusts.
While "Heat Advisory" is a specific technical term used by the NWS when the HeatRisk hits high levels, the current "above normal" trend is significant because it follows the hottest December on record. 2025 was already the second-hottest year in Phoenix history, trailing only 2024. The "winter break" from the heat just isn't happening.
New 2026 Heat Safety Laws for Workers
It’s not just the weather that's changing; the rules are too. On January 5, 2026, news broke that Arizona is finally moving toward concrete heat safety requirements for employers. Governor Katie Hobbs’ Workplace Heat Safety Task Force released recommendations that will likely become the new standard for outdoor labor.
Kinda crazy it took this long, right?
The new framework focuses on three pillars: water, shade, and rest. Employers will soon be required to have written "heat illness prevention plans." One of the most interesting parts of the proposal is the "flexibility" for rest breaks. Instead of a rigid clock, workers are encouraged to take a "cool-down rest" whenever they feel they need to prevent overheating.
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Phil Smithers from Arizona Public Service (APS) noted that while these are "best practices" for now, they provide a necessary shield for the people keeping our power on during those brutal summer spikes.
Why 2025 Data Has Experts Worried
If you look at the 2025 year-end stats, the picture is pretty grim. Phoenix endured 122 days of triple-digit heat last year. The "normal" is 111. Even scarier? Nighttime temperatures are staying high. We had 23 nights in 2025 where the mercury never dropped below 90°F.
The Maricopa County Heat Relief Network reported 156 confirmed heat-related deaths for the 2025 season by late September, with hundreds more under investigation. While that number is actually lower than the 645 deaths in 2023, Dr. Eugene Livar, Arizona's chief heat officer, warns that the public health challenge is only growing.
"Heat is not just heat stroke," Dr. Livar recently stated. "It overwhelms our first responders and emergency rooms."
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The urban heat island effect is the real culprit here. All that concrete in Mesa, Tempe, and Phoenix soaks up the sun and bleeds it out at night. It’s why the urban core almost never sees a freeze anymore. In the last decade, Phoenix Sky Harbor has only hit 32°F or lower twice.
What This Means for Your Health and Garden
Even without an official "Excessive Heat Warning" in January, this unseasonable warmth has side effects.
First, there’s the "chill hour" problem. Fruit trees like citrus and peaches need time below 45°F to set fruit properly. If Arizona keeps having record-warm Decembers and Januaries, your backyard harvest might look pretty sad come spring.
Then there's the human element. Because it’s "winter," people aren't carrying as much water as they do in July. But with 15% humidity and 77-degree sun, you can dehydrate surprisingly fast.
Actionable Steps for the Current Warm Spell:
- Check Your Irrigation: The lack of rain and high evaporation means your desert plants might need an extra drink, even if the calendar says it's winter.
- Hydrate on Trails: If you're hitting Piestewa Peak or any Valley trails this week, don't assume the "cool" breeze is enough. Drink at least one liter of water for every hour you're out.
- Watch the "Cut-off Low": Weather models show a potential cut-off low pressure system near the California coast by next weekend. This could finally bring some rain and "normal" 60-degree temps back to the desert.
- Review the New Workplace Standards: If you run a crew or work outdoors, start looking at the Arizona Division of Occupational Safety and Health (ADOSH) updates. The public hearing is set for February, and these rules will likely be in effect before the 110-degree days return.
The winter of 2026 is proving that in Arizona, the heat never truly goes away—it just takes a short, lukewarm nap. Stay weather-aware and don't let the "January" label fool you into skipping the sunscreen.