July 2025 Discussion-OBS - seasonable summer variability

[Sundog]

1 hour ago, donsutherland1 said:

July 2025 ranked among the 10 hottest Julys on record in the greater New York City area:

Monthly Mean Temperatures:

Bridgeport: 78.2° (5th hottest)
Islip: 78.5° (2nd hottest)
New York City-Central Park: 79.5° (tied 14th hottest)
New York City-JFK Airport: 79.9° (2nd hottest)
New York City-LaGuardia Airport: 81.0° (8th hottest)
Newark: 82.1° (5th hottest)

Notes: The 0.4° difference between JFK Airport and Central Park when JFK Airport had a higher mean temperature in July was the largest such difference on record. Adjusting for the trees would have led to a mean temperature near 80.0° in Central Park. That would have tied for 8th hottest. 

Amazing that the area that has changed very little around JFK (the houses were already built and have basically stayed the same) had the biggest departure in terms of ranking the hottest July. 

Obviously it's a combination of factors but the above normal ocean temps and outrageous dewpoint temps played their role and kept JFK from cooling down as much as they could have in the past. Same in Islip. 

I guess UHI warmed up the whole damn ocean! 

[bluewave]

Warmest July on record at HVN,FWN,DXR,MTP, and the Charlotteburg Reservior. 2nd warmest finish at HPN and ISP. SMQ had their 3rd warmest July and highest average maximum daily dew point at 74.3°. FWN also had their highest average maximum dew point at 72.3°. JFK had their 2nd highest average maximum dew point at 73.2° behind the record of 74.2° in 2019. So a continuation of the shift to Mid-Atlantic dew points during  summers over the last decade. 
 

Time Series Summary for CHARLOTTEBURG RESERVOIR, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.0	2
2	2020	76.1	0
3	2024	75.8	0
4	2019	75.4	0
5	1935	75.3	6
6	2010	75.1	0
7	2013	75.0	3
-	1894	75.0	8
8	1955	74.9	2
9	2023	74.3	0
-	2022	74.3	0
10	2008	74.2	16
-	1949	74.2	0

 

Time Series Summary for NEW HAVEN TWEED AP, CT - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	78.8	0
2	2013	78.6	0
3	2024	78.3	0
-	2020	78.3	0
4	2022	78.1	0
5	2023	78.0	1
6	2019	77.9	0
7	2010	77.3	0
8	2012	76.6	0
9	2011	76.4	0
10	2008	75.9	0

 

Time Series Summary for SUSSEX AIRPORT, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	76.9	0
2	2020	76.5	0
3	2024	75.7	0
4	2019	75.3	0
5	2023	74.8	0
6	2013	74.6	0
7	2011	74.5	0
8	2022	74.4	0
9	2012	74.3	0
-	2006	74.3	0
10	2010	74.1	2

 

Time Series Summary for DANBURY MUNICIPAL AP, CT - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.1	0
2	1999	76.4	8
3	2024	76.1	1
-	2023	76.1	0
4	2022	75.9	0
5	2013	75.7	0
6	2020	75.6	0
7	2010	74.7	0
8	2019	74.6	0
9	2012	74.1	0
10	2011	74.0	0

 

Time Series Summary for MONTAUK AIRPORT, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.0	3
2	2024	76.7	1
3	2023	76.5	2
4	2013	76.1	0
5	2020	75.9	0
-	2010	75.9	0
6	2022	75.5	0
-	2011	75.5	0
7	2019	75.1	0
8	2015	74.9	0
9	2012	74.7	0
10	2006	74.6	0

 

Time Series Summary for WESTCHESTER CO AP, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.5	1
2	2025	77.3	1
3	2013	77.0	0
-	2010	77.0	0
4	2020	76.9	0
5	2022	76.8	0
-	2019	76.8	0
6	1966	76.7	0
-	1955	76.7	2
7	2024	76.6	0
-	2011	76.6	1
8	2012	76.4	0
9	2016	76.3	0

 

Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.6	0
2	2025	78.5	0
3	2019	78.1	0
4	2013	78.0	0
-	2010	78.0	0
5	2020	77.7	0
6	2011	77.6	0
7	1994	77.3	0
8	2022	77.1	0
9	2023	77.0	0
10	2024	76.9	0

 

Time Series Summary for SOMERSET AIRPORT, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.5	1
2	2024	78.3	0
3	2025	78.0	0
-	2020	78.0	0
4	2022	77.9	0
5	2019	77.5	0
-	2011	77.5	0
6	2013	77.4	0
7	2012	76.9	0
8	2023	76.8	0
-	2003	76.8	25
9	2016	76.7	0
-	2010	76.7	0
10	2006	76.4	0

[LibertyBell]

9 hours ago, NorthShoreWx said:

Twas chilly at the end of August.  There was a repeat exactly 10 years later.

August 1976 also had Hurricane Belle.  Just saying.

those were some extremes, from extremely cold and sometimes extremely snowy winters to the hottest stretch this area has ever seen in July 1977.

[LibertyBell]

2 hours ago, donsutherland1 said:

July 2025 ranked among the 10 hottest Julys on record in the greater New York City area:

Monthly Mean Temperatures:

Bridgeport: 78.2° (5th hottest)
Islip: 78.5° (2nd hottest)
New York City-Central Park: 79.5° (tied 14th hottest)
New York City-JFK Airport: 79.9° (2nd hottest)
New York City-LaGuardia Airport: 81.0° (8th hottest)
Newark: 82.1° (5th hottest)

Notes: The 0.4° difference between JFK Airport and Central Park when JFK Airport had a higher mean temperature in July was the largest such difference on record. Adjusting for the trees would have led to a mean temperature near 80.0° in Central Park. That would have tied for 8th hottest. 

ugh JFK should be given 80.0, it didn't go below 80.0 until after sunset, it was basically August by then, Don

 

[LibertyBell]

2 hours ago, donsutherland1 said:

July 2025 ranked among the 10 hottest Julys on record in the greater New York City area:

Monthly Mean Temperatures:

Bridgeport: 78.2° (5th hottest)
Islip: 78.5° (2nd hottest)
New York City-Central Park: 79.5° (tied 14th hottest)
New York City-JFK Airport: 79.9° (2nd hottest)
New York City-LaGuardia Airport: 81.0° (8th hottest)
Newark: 82.1° (5th hottest)

Notes: The 0.4° difference between JFK Airport and Central Park when JFK Airport had a higher mean temperature in July was the largest such difference on record. Adjusting for the trees would have led to a mean temperature near 80.0° in Central Park. That would have tied for 8th hottest. 

adjusting for calendar BS, JFK was definitely at or above 80.0

[LibertyBell]

34 minutes ago, Sundog said:

Amazing that the area that has changed very little around JFK (the houses were already built and have basically stayed the same) had the biggest departure in terms of ranking the hottest July. 

Obviously it's a combination of factors but the above normal ocean temps and outrageous dewpoint temps played their role and kept JFK from cooling down as much as they could have in the past. Same in Islip. 

I guess UHI warmed up the whole damn ocean! 

that JFK number is BS, it was definitely at or above 80.0

I don't subscribe to this antiquated idea that the new day begins at midnight/1 am.

[LibertyBell]

18 minutes ago, bluewave said:

Warmest July on record at HVN,FWN,DXR,MTP, and the Charlotteburg Reservior. 2nd warmest finish at HPN and ISP. SMQ had their 3rd warmest July and highest average maximum daily dew point at 74.3°. FWN also had their highest average maximum dew point at 72.3°. JFK had their 2nd highest average maximum dew point at 73.2° behind the record of 74.2° in 2019. So a continuation of the shift to Mid-Atlantic dew points during  summers over the last decade. 
 

Time Series Summary for CHARLOTTEBURG RESERVOIR, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.0	2
2	2020	76.1	0
3	2024	75.8	0
4	2019	75.4	0
5	1935	75.3	6
6	2010	75.1	0
7	2013	75.0	3
-	1894	75.0	8
8	1955	74.9	2
9	2023	74.3	0
-	2022	74.3	0
10	2008	74.2	16
-	1949	74.2	0

 

Time Series Summary for NEW HAVEN TWEED AP, CT - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	78.8	0
2	2013	78.6	0
3	2024	78.3	0
-	2020	78.3	0
4	2022	78.1	0
5	2023	78.0	1
6	2019	77.9	0
7	2010	77.3	0
8	2012	76.6	0
9	2011	76.4	0
10	2008	75.9	0

 

Time Series Summary for SUSSEX AIRPORT, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	76.9	0
2	2020	76.5	0
3	2024	75.7	0
4	2019	75.3	0
5	2023	74.8	0
6	2013	74.6	0
7	2011	74.5	0
8	2022	74.4	0
9	2012	74.3	0
-	2006	74.3	0
10	2010	74.1	2

 

Time Series Summary for DANBURY MUNICIPAL AP, CT - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.1	0
2	1999	76.4	8
3	2024	76.1	1
-	2023	76.1	0
4	2022	75.9	0
5	2013	75.7	0
6	2020	75.6	0
7	2010	74.7	0
8	2019	74.6	0
9	2012	74.1	0
10	2011	74.0	0

 

Time Series Summary for MONTAUK AIRPORT, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.0	3
2	2024	76.7	1
3	2023	76.5	2
4	2013	76.1	0
5	2020	75.9	0
-	2010	75.9	0
6	2022	75.5	0
-	2011	75.5	0
7	2019	75.1	0
8	2015	74.9	0
9	2012	74.7	0
10	2006	74.6	0

 

Time Series Summary for WESTCHESTER CO AP, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.5	1
2	2025	77.3	1
3	2013	77.0	0
-	2010	77.0	0
4	2020	76.9	0
5	2022	76.8	0
-	2019	76.8	0
6	1966	76.7	0
-	1955	76.7	2
7	2024	76.6	0
-	2011	76.6	1
8	2012	76.4	0
9	2016	76.3	0

 

Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.6	0
2	2025	78.5	0
3	2019	78.1	0
4	2013	78.0	0
-	2010	78.0	0
5	2020	77.7	0
6	2011	77.6	0
7	1994	77.3	0
8	2022	77.1	0
9	2023	77.0	0
10	2024	76.9	0

 

Time Series Summary for SOMERSET AIRPORT, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.5	1
2	2024	78.3	0
3	2025	78.0	0
-	2020	78.0	0
4	2022	77.9	0
5	2019	77.5	0
-	2011	77.5	0
6	2013	77.4	0
7	2012	76.9	0
8	2023	76.8	0
-	2003	76.8	25
9	2016	76.7	0
-	2010	76.7	0
10	2006	76.4	0

July 2010 was hotter but with a lower dew point?

 

[TheClimateChanger]

3 hours ago, bluewave said:

Warmest July on record at HVN,FWN,DXR,MTP, and the Charlotteburg Reservior. 2nd warmest finish at HPN and ISP. SMQ had their 3rd warmest July and highest average maximum daily dew point at 74.3°. FWN also had their highest average maximum dew point at 72.3°. JFK had their 2nd highest average maximum dew point at 73.2° behind the record of 74.2° in 2019. So a continuation of the shift to Mid-Atlantic dew points during  summers over the last decade. 
 

Time Series Summary for CHARLOTTEBURG RESERVOIR, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.0	2
2	2020	76.1	0
3	2024	75.8	0
4	2019	75.4	0
5	1935	75.3	6
6	2010	75.1	0
7	2013	75.0	3
-	1894	75.0	8
8	1955	74.9	2
9	2023	74.3	0
-	2022	74.3	0
10	2008	74.2	16
-	1949	74.2	0

 

Time Series Summary for NEW HAVEN TWEED AP, CT - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	78.8	0
2	2013	78.6	0
3	2024	78.3	0
-	2020	78.3	0
4	2022	78.1	0
5	2023	78.0	1
6	2019	77.9	0
7	2010	77.3	0
8	2012	76.6	0
9	2011	76.4	0
10	2008	75.9	0

 

Time Series Summary for SUSSEX AIRPORT, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	76.9	0
2	2020	76.5	0
3	2024	75.7	0
4	2019	75.3	0
5	2023	74.8	0
6	2013	74.6	0
7	2011	74.5	0
8	2022	74.4	0
9	2012	74.3	0
-	2006	74.3	0
10	2010	74.1	2

 

Time Series Summary for DANBURY MUNICIPAL AP, CT - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.1	0
2	1999	76.4	8
3	2024	76.1	1
-	2023	76.1	0
4	2022	75.9	0
5	2013	75.7	0
6	2020	75.6	0
7	2010	74.7	0
8	2019	74.6	0
9	2012	74.1	0
10	2011	74.0	0

 

Time Series Summary for MONTAUK AIRPORT, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	2025	77.0	3
2	2024	76.7	1
3	2023	76.5	2
4	2013	76.1	0
5	2020	75.9	0
-	2010	75.9	0
6	2022	75.5	0
-	2011	75.5	0
7	2019	75.1	0
8	2015	74.9	0
9	2012	74.7	0
10	2006	74.6	0

 

Time Series Summary for WESTCHESTER CO AP, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.5	1
2	2025	77.3	1
3	2013	77.0	0
-	2010	77.0	0
4	2020	76.9	0
5	2022	76.8	0
-	2019	76.8	0
6	1966	76.7	0
-	1955	76.7	2
7	2024	76.6	0
-	2011	76.6	1
8	2012	76.4	0
9	2016	76.3	0

 

Time Series Summary for ISLIP-LI MACARTHUR AP, NY - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.6	0
2	2025	78.5	0
3	2019	78.1	0
4	2013	78.0	0
-	2010	78.0	0
5	2020	77.7	0
6	2011	77.6	0
7	1994	77.3	0
8	2022	77.1	0
9	2023	77.0	0
10	2024	76.9	0

 

Time Series Summary for SOMERSET AIRPORT, NJ - Month of Jul
Click column heading to sort ascending, click again to sort descending.

1	1999	78.5	1
2	2024	78.3	0
3	2025	78.0	0
-	2020	78.0	0
4	2022	77.9	0
5	2019	77.5	0
-	2011	77.5	0
6	2013	77.4	0
7	2012	76.9	0
8	2023	76.8	0
-	2003	76.8	25
9	2016	76.7	0
-	2010	76.7	0
10	2006	76.4	0

Wow, since 1970, July nighttime low temperatures at NYC have risen 3.1F, while lows at Charlotteburg Reservoir have risen 7.1F, per linear regression.

[TheClimateChanger]

Just now, TheClimateChanger said:

Wow, since 1970, July nighttime low temperatures at NYC have risen 3.1F, while lows at Charlotteburg Reservoir have risen 7.1F, per linear regression.

You can even see the point where atmospheric changes start to swamp out the UHI signal. From 1970-2000, both sites show a small cooling trend, with NYC lows dropping 0.2F, while the Charlotteburg site saw lows drop by 0.7F during that timeframe. Hard to tell if the late 20th century cooling is a real trend or just an artifact from changing equipment/observation practices and site location. I'm not sure if that cooling trend is real or just manufactured by those non-climatic factors.

[LibertyBell]

13 minutes ago, TheClimateChanger said:

You can even see the point where atmospheric changes start to swamp out the UHI signal. From 1970-2000, both sites show a small cooling trend, with NYC lows dropping 0.2F, while the Charlotteburg site saw lows drop by 0.7F during that timeframe. Hard to tell if the late 20th century cooling is a real trend or just an artifact from changing equipment/observation practices and site location. I'm not sure if that cooling trend is real or just manufactured by those non-climatic factors.

it's not really cooling, maxes have stabilized while mins are climbing so overall it's still warming.

 

[TheClimateChanger]

10 minutes ago, LibertyBell said:

it's not really cooling, maxes have stabilized while mins are climbing so overall it's still warming.

 

Wow, I don't agree with this statement at all. Recent Julys have had mean minimum temperatures that are warmer than the mean 24-hour averages from past "cold" Julys. Probably after 2050, we will begin to see Julys where the mean minimum temperatures exceed the mean maximum temperatures from old-school cold Julys. For some reason, you only ever look and compare to the hottest years?

For example, JFK's mean minimum last month was 72.7F. That exceeds the mean 24-hour average of 71.8F in 1956, 72.2F in 1996, 72.2F in 1965, 72.3F in 2000, 72.4F in 2001, and falls just shy of the 72.8F observed in 1976. It's probably just a handful of decades before JFK starts seeing low temperatures in July that exceed the mean maximum temperatures observed in cold Julys (e.g., 1956, 77.9F; 1996, 78.6F; 2000, 79.5F; and 1967, 79.7F). I don't think its too hard to imagine a future in 2060 where NYC looks more like Washington, DC of 2000-2020, where such low temperatures are common.

I think it's significant when low temperatures are exceeding the mean of high and low from many past years. In the first 6 years after installation of the ASOS at JFK, there were 3 years in which the month of July had a colder mean temperature than this year's mean low temperature (1996, 2000, and 2001).

[Sundog]

1 hour ago, TheClimateChanger said:

Wow, since 1970, July nighttime low temperatures at NYC have risen 3.1F, while lows at Charlotteburg Reservoir have risen 7.1F, per linear regression.

Well Charlotteburg is the biggest city in the country, after all. 

[LibertyBell]

1 hour ago, TheClimateChanger said:

Wow, I don't agree with this statement at all. Recent Julys have had mean minimum temperatures that are warmer than the mean 24-hour averages from past "cold" Julys. Probably after 2050, we will begin to see Julys where the mean minimum temperatures exceed the mean maximum temperatures from old-school cold Julys. For some reason, you only ever look and compare to the hottest years?

For example, JFK's mean minimum last month was 72.7F. That exceeds the mean 24-hour average of 71.8F in 1956, 72.2F in 1996, 72.2F in 1965, 72.3F in 2000, 72.4F in 2001, and falls just shy of the 72.8F observed in 1976. It's probably just a handful of decades before JFK starts seeing low temperatures in July that exceed the mean maximum temperatures observed in cold Julys (e.g., 1956, 77.9F; 1996, 78.6F; 2000, 79.5F; and 1967, 79.7F). I don't think its too hard to imagine a future in 2060 where NYC looks more like Washington, DC of 2000-2020, where such low temperatures are common.

I think it's significant when low temperatures are exceeding the mean of high and low from many past years. In the first 6 years after installation of the ASOS at JFK, there were 3 years in which the month of July had a colder mean temperature than this year's mean low temperature (1996, 2000, and 2001).

I think you misread what I wrote: what you stated here is what I said, the mins are rapidly increasing, the maxes are not rapidly increasing, they are relatively stable (it could be a small increase but not anything like the rapid rate of the mins increase.) So the daily range is much less (the difference between min and max.)  I don't disagree with what you wrote about 2050 either, it's just that we are not there yet.

 

Recent Julys have had mean minimum temperatures that are warmer than the mean 24-hour averages from past "cold" Julys. Probably after 2050, we will begin to see Julys where the mean minimum temperatures exceed the mean maximum temperatures from old-school cold Julys.