Phoenix Experiences Warmest February and Winter on Record

[donsutherland1]

Phoenix experienced its warmest February on record with a monthly mean temperature of 67.7°. That broke the prior record of 66.0°, which was set in 1991 and tied just last year.

 

Powered by the warmest December and February on record, Phoenix experienced its warmest winter on record, by far. Its winter mean temperature of 63.9° was similar to a typical winter in Melbourne, FL. Its seasonal mean temperature also exceeded the figure from March-May 1917.

Table 6: Winter and Spring Mean Temperatures:

 

 

 

[donsutherland1]

For what it's worth, it appears that global temperatures explain a larger share of Phoenix's (and perhaps the Southwest's) annual temperature variance than they do for such cities as New York.

[Stormchaserchuck1]

Records just keep dropping in PHX, does it have the greatest rate of warming in the world, of major cities? 

[Typhoon Tip]

It's almost like there is built in synergistic feed-back now, anywhere outside of direct polar sourced modulation/forcing on Earth.  

Where ever there is warm look to an outlook, relative to region, ... it seems to become historic more commonly than not.  Regardless of where. 

The aspect ( Meteorologically...) that enhances that prospect for PHX most likely has to do with the perennial flow across N/A, which features a flat ridge over the continental cordillera, tending to nadir as a flat trough exiting the east.  PHX, and surrounding of the S/W - which by the way has just registered the warmest winter ever from Canada to Mexico, reside within that flat ridge.  That supplies a perpetual positive/constructive resonance potential at all times.  It's not major... but, when we are dealing with synergy, the whole product after smaller additive forcing, tends to be larger than amount of the individual addition.  You add 1 to 10 ... you get 12 so to speak. 

In other words, this gives them a bit of an advantage.  There may be some urban expansion feed backs as well - I haven't heard/read of any studies that use scientifically discipline in conjunction with mathematics which quantifies how much. Not beyond speculation.  It's likely fractionally playing a role but cannot atone for the whole occurrences.

Nor does that diminish the significance of the record breaking occurrences, nor the standard elevated mean temperatures - in fact, .. it substantiates "why" that is happening.  Particularly when considering how well that fits in with the planet as a whole, where warm events are consummately over performing above leading predictive indicators/methods.

[donsutherland1]

For a further illustration of how remarkable the warmth has been in recent years, seven months have now seen their highest average temperature set since 2020. So far, no records have been set in any of the spring months. However, there is a chance that could change this month. With its sizzling start and possible near-record/record heat next week, 2026 is very likely to finish among the 10 warmest years on record in March. A new record is possible should the predominant winter pattern persist through much of the month.

[Stormchaserchuck1]

Models look really warm for Phoenix again mid to late March. They might break their March record.

[donsutherland1]

16 minutes ago, Stormchaserchuck1 said:

Models look really warm for Phoenix again mid to late March. They might break their March record.

Yes. There's a strong indication of heat on the guidance.

[frontranger8]

On 3/7/2026 at 6:47 AM, donsutherland1 said:

For a further illustration of how remarkable the warmth has been in recent years, seven months have now seen their highest average temperature set since 2020. So far, no records have been set in any of the spring months. However, there is a chance that could change this month. With its sizzling start and possible near-record/record heat next week, 2026 is very likely to finish among the 10 warmest years on record in March. A new record is possible should the predominant winter pattern persist through much of the month.

And again, over the same period Flagstaff has experienced 2 record warm months to Phoenix's 7.

Yes, the Southwest has been warming faster than most places recently. And yes also, Phoenix is an extreme outlier in this trend. Yet it's always the one place pointed out on here with all the records.

[donsutherland1]

1 hour ago, frontranger8 said:

And again, over the same period Flagstaff has experienced 2 record warm months to Phoenix's 7.

Yes, the Southwest has been warming faster than most places recently. And yes also, Phoenix is an extreme outlier in this trend. Yet it's always the one place pointed out on here with all the records.

Flagstaff has four such months: June (2024), July (2023), August (2020), and October (2024).

Record Warm Months have been common in the Southwest since 2020: 

8, Salt Lake City and Tucson
7, Phoenix
6, Las Vegas
5, Albuquerque, Palm Springs and Reno
4, Flagstaff
2, Denver

Flagstaff's record warmest months with records set in 2020 or later are June, July, August, and October.

[TheClimateChanger]

12 hours ago, donsutherland1 said:

Flagstaff has four such months: June (2024), July (2023), August (2020), and October (2024).

Record Warm Months have been common in the Southwest since 2020: 

8, Salt Lake City and Tucson
7, Phoenix
6, Las Vegas
5, Albuquerque, Palm Springs and Reno
4, Flagstaff
2, Denver

Flagstaff's record warmest months with records set in 2020 or later are June, July, August, and October.

Don, it's CLEARLY urban heat island effect. That's why the 10 warmest years at Death Valley (pop: 0) are 2022, 2021, 2025, 2018, 2017, 2024, 2020, 2014, 2012, and 2016. Note the handful of older years are all missing months, mostly in the cold part of the year. It's actually pretty wild that recent years are as warm as those years that have no data for one or more winter months. 

 

[frontranger8]

On 3/9/2026 at 8:00 PM, donsutherland1 said:

Flagstaff has four such months: June (2024), July (2023), August (2020), and October (2024).

Record Warm Months have been common in the Southwest since 2020: 

8, Salt Lake City and Tucson
7, Phoenix
6, Las Vegas
5, Albuquerque, Palm Springs and Reno
4, Flagstaff
2, Denver

Flagstaff's record warmest months with records set in 2020 or later are June, July, August, and October.

Flagstaff had some very hot summers in the late 1800s: https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?az3010

It's very possible that their was a thermometer is those summers, though 1898 in particular was hot throughout the region. But those are the official records for Flagstaff per the WRCC.

[frontranger8]

On 3/9/2026 at 8:00 PM, donsutherland1 said:

Flagstaff has four such months: June (2024), July (2023), August (2020), and October (2024).

Record Warm Months have been common in the Southwest since 2020: 

8, Salt Lake City and Tucson
7, Phoenix
6, Las Vegas
5, Albuquerque, Palm Springs and Reno
4, Flagstaff
2, Denver

Flagstaff's record warmest months with records set in 2020 or later are June, July, August, and October.

Here's some other locations with long term records. All of these have far less UHI than Phoenix, SLC, or Vegas.

Santa Fe: 4 (but missing a ton of years prior to 1997)

Roswell: 5

Las Vegas, NM: 3

Gallup, NM: 4 (records only back to 1973)

Mesa Verde NP: 2

Imperial, CA: 3

Barstow, CA: 5

Blythe, CA: 2

Winslow, AZ: 5

Prescott, AZ: 3

The mean is around 3-4. Clearly Phoenix's 7 is an outlier, as asserted.

 

 

[donsutherland1]

3 hours ago, frontranger8 said:

Here's some other locations with long term records. All of these have far less UHI than Phoenix, SLC, or Vegas.

Santa Fe: 4 (but missing a ton of years prior to 1997)

Roswell: 5

Las Vegas, NM: 3

Gallup, NM: 4 (records only back to 1973)

Mesa Verde NP: 2

Imperial, CA: 3

Barstow, CA: 5

Blythe, CA: 2

Winslow, AZ: 5

Prescott, AZ: 3

The mean is around 3-4. Clearly Phoenix's 7 is an outlier, as asserted.

 

 

Yes, Phoenix has UHI, and I've often noted that the combination of UHI and climate change are responsible for the outcome. My main point is that a disproportionate share of the warmest months have occurred since 2020.

[Stormchaserchuck1]

EPS yesterday had PHX hitting 101 on March 19. Today the 12z EPS mean has 100, 101, 101, March 19-21

[TheClimateChanger]

3 hours ago, donsutherland1 said:

Yes, Phoenix has UHI, and I've often noted that the combination of UHI and climate change are responsible for the outcome. My main point is that a disproportionate share of the warmest months have occurred since 2020.

Thanks, Don. I agree there's a UHI component as well, but it's not impacting the trends. Whereas Phoenix has warmed at about .6F/decade since 1896, NCEI has the State of Arizona warming at about a third of that rate (0.2F/decade), so it's not like they are just using Phoenix numbers to calculate the official trends and departures.

By the way, Death Valley - with a population of, checks notes, zero - has 4. But really 6, as the numbers for November & December in 1913 & 1914 are clearly erroneous. The huge surpluses were driven by implausibly high temperatures with impossibly small diurnal ranges that make zero sense in winter in Death Valley. Ignoring those months, it's 6 of 12.