Occasional Thoughts on Climate Change

[tacoman25]

24 minutes ago, bluewave said:

If you look at the JJA 20 year trend from 1995 to 2024, then the high/low trend is nearly identical for both stations. The minimums are rising at a faster pace for both locations. Obviously, Phoenix gets the most attention since the actual temperatures are significantly higher. But the temperature increase at both locations has been the same even at significantly different altitudes.

https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/city/time-series/USW00003103/tmin/3/8/1995-2024?trend=true&trend_base=10&begtrendyear=1995&endtrendyear=2025&filter=true&filterType=binomial

1995-2024 temperature trend 

Phoenix……max…+0.8°F/Decade….min…+1.0°F/Decade

Flagstaff…..max…+0.7°F/Decade…min…..+.1.1°F/Decade

 

That's 30 years. And obviously the exact starting point matters...depending on if you start in 1970, 1980, 1995, 2005, 2010 you'll get differing trend numbers.

But again, July/August is the primary monsoon season (rarely does it start until late June/early July, sometimes not until mid July). Including June makes about as much since if not less than including September.

If I go as far back as the data allows (1933) and plot JJAS avg temp trend for Flagstaff, it's .3F/decade. For Phoenix, it's twice as much with .6F/decade. Same trend for JJA if you prefer that.

[donsutherland1]

21 minutes ago, GaWx said:

 Chris,

 Don and I have had discussions about the UHI portion of the warming at Phoenix over the last 30-40+ years due to the tremendous population growth. We agreed that the UHI portion isn’t at all insignificant if I’m recalling this correctly.

@donsutherland1

Yes, that’s correct. Phoenix has a pronounced UHI effect. One sees it particularly in the explosive increase in 90 or above low temperatures.

[tacoman25]

All trendlines aside, in practical, very recent terms:

- Phoenix was 3 degrees above their long term average in July 2025. Flagstaff was exactly average.

- Phoenix was a ridiculous 9 degrees above their long term mean in July 2023. That same month, Flagstaff was about 5 degrees above theirs.

- Phoenix hasn't had a June below their long term mean since 2009. Flagstaff's most recent was 2023.

- Phoenix's hottest year on record was 2024. Flagstaff's was 1981.

 

[tacoman25]

3 minutes ago, donsutherland1 said:

Yes, that’s correct. Phoenix has a pronounced UHI effect. One sees it particularly in the explosive increase in 90 or above low temperatures.

The last time Phoenix had an August with average low temps below their long term mean was 1990.

Flagstaff did it in 2017, 2016, and 2014. Along with a bunch of other years since 1990.

[bluewave]

13 minutes ago, tacoman25 said:

That's 30 years. And obviously the exact starting point matters...depending on if you start in 1970, 1980, 1995, 2005, 2010 you'll get differing trend numbers.

But again, July/August is the primary monsoon season (rarely does it start until late June/early July, sometimes not until mid July). Including June makes about as much since if not less than including September.

If I go as far back as the data allows (1933) and plot JJAS avg temp trend for Flagstaff, it's .3F/decade. For Phoenix, it's twice as much with .6F/decade. Same trend for JJA if you prefer that.

The 2020s has produced unprecedented summer warmth for both locations. Flagstaff and Phoenix both had their warmest summers on record in 2024 by a significant margin. All the 2020s summers have been in the top 10 for warmth which has never happened before.

Time Series Summary for Flagstaff Area, AZ (ThreadEx) 10 Warmest Summers dense rank sorting by temperature 
Click column heading to sort ascending, click again to sort descending.

1	2024	68.4	0
2	1981	66.6	0
3	2002	66.3	0
4	2025	66.2	13
5	2021	66.1	0
6	2020	65.8	0
-	2007	65.8	0
-	1974	65.8	0
-	1940	65.8	0
7	2018	65.6	0
8	2022	65.4	0
-	2008	65.4	0
-	1980	65.4	0
9	2012	65.3	0
-	1946	65.3	0
10	2023	65.2	0
-	2017	65.2	0
-	1996	65.2	0
-	1977	65.2	0

 

Time Series Summary for Phoenix Area, AZ (ThreadEx)10 Warmest Summers dense rank sorting by temperature  
Click column heading to sort ascending, click again to sort descending.

1	2024	98.9	0
2	2023	97.0	0
3	2025	96.7	13
-	2020	96.7	0
4	2015	95.1	0
-	2013	95.1	0
5	2019	94.9	0
-	2007	94.9	0
6	2011	94.8	0
-	2002	94.8	0
-	1981	94.8	0
7	2022	94.7	0
8	2017	94.6	0
-	2016	94.6	0
-	2003	94.6	0
9	2006	94.5	0
10	1989	94.4	0
-	1988	94.4	0

[rclab]

12 minutes ago, bluewave said:

The 2020s has produced unprecedented summer warmth for both locations. Flagstaff and Phoenix both had their warmest summers on record in 2024 by a significant margin. All the 2020s summers have been in the top 10 for warmth which has never happened before.

Time Series Summary for Flagstaff Area, AZ (ThreadEx) 10 Warmest Summers dense rank sorting by temperature 
Click column heading to sort ascending, click again to sort descending.

1	2024	68.4	0
2	1981	66.6	0
3	2002	66.3	0
4	2025	66.2	13
5	2021	66.1	0
6	2020	65.8	0
-	2007	65.8	0
-	1974	65.8	0
-	1940	65.8	0
7	2018	65.6	0
8	2022	65.4	0
-	2008	65.4	0
-	1980	65.4	0
9	2012	65.3	0
-	1946	65.3	0
10	2023	65.2	0
-	2017	65.2	0
-	1996	65.2	0
-	1977	65.2	0

 

Time Series Summary for Phoenix Area, AZ (ThreadEx)10 Warmest Summers dense rank sorting by temperature  
Click column heading to sort ascending, click again to sort descending.

1	2024	98.9	0
2	2023	97.0	0
3	2025	96.7	13
-	2020	96.7	0
4	2015	95.1	0
-	2013	95.1	0
5	2019	94.9	0
-	2007	94.9	0
6	2011	94.8	0
-	2002	94.8	0
-	1981	94.8	0
7	2022	94.7	0
8	2017	94.6	0
-	2016	94.6	0
-	2003	94.6	0
9	2006	94.5	0
10	1989	94.4	0
-	1988	94.4	0

Amazing BW ….. 3 of the top 5 occurred within the last 4 years. As always …..

[tacoman25]

43 minutes ago, bluewave said:

The 2020s has produced unprecedented summer warmth for both locations. Flagstaff and Phoenix both had their warmest summers on record in 2024 by a significant margin. All the 2020s summers have been in the top 10 for warmth which has never happened before.

Time Series Summary for Flagstaff Area, AZ (ThreadEx) 10 Warmest Summers dense rank sorting by temperature 
Click column heading to sort ascending, click again to sort descending.

1	2024	68.4	0
2	1981	66.6	0
3	2002	66.3	0
4	2025	66.2	13
5	2021	66.1	0
6	2020	65.8	0
-	2007	65.8	0
-	1974	65.8	0
-	1940	65.8	0
7	2018	65.6	0
8	2022	65.4	0
-	2008	65.4	0
-	1980	65.4	0
9	2012	65.3	0
-	1946	65.3	0
10	2023	65.2	0
-	2017	65.2	0
-	1996	65.2	0
-	1977	65.2	0

 

Time Series Summary for Phoenix Area, AZ (ThreadEx)10 Warmest Summers dense rank sorting by temperature  
Click column heading to sort ascending, click again to sort descending.

1	2024	98.9	0
2	2023	97.0	0
3	2025	96.7	13
-	2020	96.7	0
4	2015	95.1	0
-	2013	95.1	0
5	2019	94.9	0
-	2007	94.9	0
6	2011	94.8	0
-	2002	94.8	0
-	1981	94.8	0
7	2022	94.7	0
8	2017	94.6	0
-	2016	94.6	0
-	2003	94.6	0
9	2006	94.5	0
10	1989	94.4	0
-	1988	94.4	0

Right, no one is disputing it's been hot in Flagstaff. It just hasn't warmed as much as Phoenix, as those stats clearly show. It's a distinct difference.

- Two of Flagstaff's top 3 warmest summers happened more than 20 years ago. Meanwhile, those same two summers are tied for 6th hottest in Phoenix, and their three hottest are the last three summers.

- Flagstaff has 5 summers among their 10 warmest that occurred 2007 or earlier. Phoenix has 2.

- Flagstaff has a total of 7 20th century summers on their list. Phoenix has 3.

- Phoenix's hottest summer is more than 4 degrees warmer than their hottest 20th century summer. Flagstaff's is less than 2 degrees warmer.

[bluewave]

1 hour ago, GaWx said:

 Chris,

 Don and I have had discussions about the UHI portion of the warming at Phoenix over the last 30-40+ years due to the tremendous population growth. We agreed that the UHI portion isn’t at all insignificant if I’m recalling this correctly.

@donsutherland1

UHI acts as an amplifier of mostly the low temperatures in and around Phoenix leading to the rapid increase in 80° minimums there. But the rapid increase in 100°+ maxes is evenly distributed across, urban, suburban, and rural locations. It’s the rapid warming of the planet which is driving the increasing intensity of the heat.

So the UHI acts to keep the urban centers warmer at night than the outlying areas. But both areas as seeing steep increases in the minimum and maximum temperatures. So without the background warming of the climate, the UHI alone wouldn’t be nearly as significant. 

 

[Typhoon Tip]

4 hours ago, bluewave said:

UHI acts as an amplifier of mostly the low temperatures in and around Phoenix leading to the rapid increase in 80° minimums there. But the rapid increase in 100°+ maxes is evenly distributed across, urban, suburban, and rural locations. It’s the rapid warming of the planet which is driving the increasing intensity of the heat.

So the UHI acts to keep the urban centers warmer at night than the outlying areas. But both areas as seeing steep increases in the minimum and maximum temperatures. So without the background warming of the climate, the UHI alone wouldn’t be nearly as significant. 

 

It just gets exhausting trying to explain this to the people that can’t synthesize global perspectives; probably as a native intellectual limitation. Which unfortunately is precisely what is needed if somebody’s going to understand how global warming works  

Dimes to donuts the majority of the people in the denier frame of mine are narrow perspective types