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UHI Proves Global Warming!

July 7, 2018

By Paul Homewood


It’s summer time in the Northern Hemisphere, and it’s hot in places, but according to  Jason Samenow of the Washington Post, you must blame it global warming!

Reposted from the NZ Herald:


From the normally mild summer climes of Ireland, Scotland and Canada to the scorching Middle East, numerous locations in the Northern Hemisphere have witnessed their hottest weather ever recorded over the past week.

Large areas of heat pressure or heat domes scattered around the hemisphere led to the sweltering temperatures.

No single record, in isolation, can be attributed to global warming. But collectively, these heat records are consistent with the kind of extremes we expect to see increase in a warming world.

Let’s take a tour around the world of the recent hot-weather milestones.

North America

A massive and intense heat dome has consumed the eastern two-thirds of the United States and southeast Canada since late last week. It’s not only been hot but also exceptionally humid. Here are some of the notable all-time records set:

• Denver tied its all-time high-temperature record of 40.5 Celsius on Thursday.

• Mount Washington, New Hampshire, tied its all-time warmest low temperature of 15.5C on Monday.

• Burlington, Vermont, set its all-time warmest low temperature ever recorded of 26.6C on Monday.

• Montreal recorded its highest temperature in recorded history, dating back 147 years, of 36.6C on Monday. The city also posted its most extreme midnight combination of heat and humidity.

• Ottawa posted its most extreme combination of heat and humidity on Sunday.


Excessive heat torched the British Isles late last week. The stifling heat caused roads and roofs to buckle, the Weather Channel reported, and resulted in multiple record highs:

• Scotland provisionally set its hottest temperature on record. The UK Met Office reported Motherwell, about 20km southeast of Glasgow, hit 33.2C on Thursday, passing the previous record set in August 2003 at Greycrook. Additionally, Glasgow had its hottest day on record, hitting 31.9.

• In Ireland, on Thursday, Shannon hit 32C, its record.

• In Northern Ireland, Belfast hit 29.5C on Thursday, its record, and Castlederg hit 30.1C on Friday, its record


A large dome of high pressure, or heat dome, has persistently sat on top of Eurasia over the past week, resulting in some extraordinarily hot weather:

• In Tbilisi, Georgia, on Wednesday, the capital city soared to 40.5C, its all-time record.

• In Yerevan, Armenia, on Monday, the capital city soared to 42C, a record high for July and tying its record for any month.

So how do his claims stack up?

1) Denver

You will note that Samenow likes to quote big city sites, which are heavily affected by UHI. The record of 105F was registered at Denver International Airport, according to NWS.

Yet the all-time State record temperatures for Colorado were set in 1933 and 1954, long before Denver International Airport was opened in 1995.


In fact, if we check all the US State records, we find that the vast majority were set in the 1930s. Only two occur this century, S Carolina and S Dakota, and the latter only ties 1936 anyway.







It is extremely dishonest to use heavily UHI affected sites to claim temperatures are increasing because of global warming.

2) Montreal

For Montreal, read Denver, except the temperature reading was in the city itself, rather than the airport, which would make UHI worse still.

As with the US, nearly all of Canada’s all time state records occurred in the 1930s.

There is no coincidence about this. The infamous heatwaves of the dustbowl years were not simply localised events over a couple of summers, as is sometimes suggested. They affected most of North America throughout the decade.


Samenow talks dramatically about “heatdomes”, but these are simply areas of high pressure. As Environment Canada explained in a previous heatwave in 2011:

The heat dome phenomenon happens every few summers.”


And if he wants to blame single weather events on global warming, he might like to explain why Montreal suffered its coldest February in history – just three years ago.


UK & Ireland

As we know, that “Scottish record temperature claim” has had to be withdrawn, much to the embarrassment of alarmists.

In England, the CET series showed last month as only the 10th warmest June, with the hottest occurring as long ago as 1846.

The highest temperature in N Ireland was 30.1C, well below the record of 30.8C set in 1976 and 1983.

As for Ireland, Shannon International Airport may have set a record of 32C, confirmed by the Ireland Met Office as the  highest temperature anywhere in the country last month. But this was also well below the all-time record at Kilkenny in 1887, not to mention the 20thC record of 32.5C in 1976.




Samenow also quotes records at a couple of places in Asia, but both Tblisi and Yerevan, which he refers to, have both expanded massively in recent decades, both in terms of population and infrastructure.

Yerevan, for instance, has an estimated population of 1.1m, five times the size in 1939. The temperature is measured slap bang in the middle of an extremely built up city.




Tblisi too has grown in leaps and bounds, with population rising from 500K in 1939 to an estimated 1.5m now.

Hot Weather

Nobody would deny that there has been a lot of hot weather around in the UK, US and doubtless other places lately.

But they are certainly not unprecedented, and temperatures have been consistently well below other notoriously hot summers in the past.

To pretend that city and airport sites, where UHI artificially raises temperatures significantly, are representative of some sort of new climate is junk science, which meteorologists like Jason Samenow should be ashamed of peddling.

  1. quaesoveritas permalink
    July 7, 2018 2:59 pm

    “• Scotland provisionally set its hottest temperature on record. The UK Met Office reported Motherwell, about 20km southeast of Glasgow, hit 33.2C on Thursday, passing the previous record set in August 2003 at Greycrook. Additionally, Glasgow had its hottest day on record, hitting 31.9.”

    Unfortunately the lie is perpetuated!

  2. Up2snuff permalink
    July 7, 2018 3:55 pm

    “All-time heat records have been set all over the world during the past week.”

    They sure have. That is if low heat is included with high heat. Did I hear correctly that there has been snow in South Africa where it does not usually have snow in winter? And that things have been a bit extra chilly, ie. cold – not ‘extra chillis with that’, in parts of Australia?

    It is great to have a really good summer across the UK, the best since records began demonstrating Global Warming … er, no, sorry … the best since 1976 BAGW. (Before AGW). Been a long time coming.

  3. Athelstan permalink
    July 7, 2018 4:52 pm

    WaPo……….seeesh, they’re almost as bad as the NYT, global warming activists is all they are.

  4. July 7, 2018 5:53 pm


    You say “Did I hear correctly that there has been snow in South Africa where it does not usually have snow in winter?”

    In fact we do regularly have snow in winter in South Africa. The high mountains of the Drakensberg and the Malutis, on the border with Lesotho, are frequently covered in snow in winter. In the past week, the high mountains of the Western Cape have also received large falls of snow.

    Cape Town and the Western Cape Province, on the southern tip of Africa, are in a Mediterranean type of climate regime, with dry summers and wet winters. The interior of South Africa, on the other hand, typically has very dry winters and rainfall in summer.

    With modern access to Internet weather sites like YR and Accuweather, it is fascinating to look at their satellite images to see that South Africa is a not too-distant province of Antarctica, as waves of cold fronts race northwards across the Atlantic to bring freezing cold (and welcome rain) to the southern outposts of Africa.

    There has been a lot of local and international news about ‘Cape Town being the first major city in the world to run out of water’, and of course the populist media and activists have laid the blame on ‘climate change’ caused by our use of fossil fuels. Even our usually sane (but new) President has been suckered into blaming ‘climate change’ for Cape Town’s water woes.

    As Paul has shown on this website, the average rainfall in South Africa has remained the same for at least the past one hundred years. Sure, annual rainfall goes up and down, year on year, and sure, Cape Town has had a couple of below average years. But this is quite normal, and has nothing to do with ‘climate change’ and fossil fuels.

    What has changed dramatically around Cape Town is a massive population increase as people from impoverished rural areas flock to the city in search of better lives, as well as a lot of political posturing and shenanigans between the majority ruling party in the country, the African National Congress, and the minority party (the Democratic Alliance) that is running Cape Town rather well and efficiently, in contrast to the shambles that prevails in most ANC-run municipalities in South Africa.

    The good news is that recent heavy rain in the catchments of Cape Town’s main supply dams has lifted their average levels to above 40%, meaning that their ‘crisis’ has been averted for now. I suspect that Antarctica will send a few more parcels of water to Cape Town before the wet winter months end. Rather like a Father Christmas bring gifts from the South Pole for a change!

    John Ledger

  5. July 7, 2018 6:23 pm

    There are two major airports in Montreal area: MONTREAL MIRABEL INTL A and Pierre Elliot Trudeau International. Mirabel is several Km from downtown Montreal and is actually in the country while Pierre Elliot Trudeau airport is surrounded by the city of Montreal.
    It was 35.3 degrees C at the Pierre Elliot Trudeau International airport on Monday. At MIRABEL it was 33.6 degrees C. Both these readings are lower than downtown reading.

  6. Broadlands permalink
    July 7, 2018 7:24 pm

    The weather of 1921 in the US and other parts of the world was similarly weird and wild…

    Click to access mwr-049-07-0418.pdf

    Some excerpts:

    BRITISH ISLES: London, July 10. England is sweltering and suffering the worst drought in a century. Today was the seventy-eighth virtually rainless day. For the third successive day temperatures have exceeded 100.

    FRANCE: Paris July 12. The Senate yesterday… cancelled the usual July 14 military review in Longchamps owing to the extreme heat.

    ITALY: July 30. The principal phenomenon…was the intensely hot weather. An unprecedented heat wave continued to develop in its intensity of heat and in its length and duration.

    RUSSIA: July 17. Twenty million persons are on the verge of starvation in drought-stricken sections of Russia. The parched earth…is opening up great crevices, and wells and rivers are drying up.

    SWITZERLAND: July 26. On the summit of the Wellenkuppe, above Zermatt, and 12,830 feet high, the temperature at 10 o’clock in the morning has exceeded 100°F.

    1921 the warmest year on record only four years after the coldest…1917.

    Carbon dioxide… Barely above pre-industrial?

  7. quaesoveritas permalink
    July 7, 2018 7:26 pm

    The Metro wades in:

    “Up to 50 motorists were left with their tyres covered in bitumen that had melted on a stretch of road outside the Australian city of Cairns in northern Queensland. Tablelands regional mayor Joe Paronella said: ‘I have never seen anything like it.’”

    As Cairns is in the tropics it must be hot all of the year round.

    They are incorrect in stating that Montreal is the capital of Quebec.

  8. July 7, 2018 8:37 pm

    One unusual feature of the current UK heatwave is the almost total absence of clouds, even fair weather (cumulus) ones. At the same time the humidity seems high. Is this just a wiggly jet stream thing?

    • Gerry, England permalink
      July 7, 2018 9:03 pm

      I wonder what those strange things in the sky were today and yesterday that hid the sun at times?

    • quaesoveritas permalink
      July 7, 2018 11:06 pm

      Plenty of clouds on the NE coast, but not much rain.

    • July 8, 2018 8:17 am

      We’ve had plenty of cloud up in North Lincolnshire.

      Very frequently over last few weeks we’ve had strong breezes move in at teatime, strong enough to threaten the gazebo. This has been accompanied by lots of cloud and sudden drops in temp. We’ve seen temp drops of 10c in 2 hours regularly during this warm spell. This has led to us eating indoors rather than out as conditions deteriorated so quick just as we were about to eat evening meal outdoors.

      Humidity often increases from 55% to 75% at these times too. I think the reason for lack of rain is that the weather system is easterly not westerly, unusual for UK summer, especially in last 20 years. It is pulling air in off near continent which doesn’t pass over a long enough stretch of water to pick up enough moisture?

      Jet stream is due to relocate south soon which means a return to Atlantic driven pattern eg. Rain. I think we should appreciate the warm dry spell for what it is, a nice summer. I dare say wet, miserable normality will return eventually and I would not be surprised to see another cold winter too. The media have such short memories, only 4 months ago we had record cold.

  9. martinbrumby permalink
    July 7, 2018 9:09 pm

    Tblisi &Yerevan are usually counted as European.

    More interesting, have you seen the UK wind generation figures over the last two months?

  10. Curious George permalink
    July 7, 2018 11:38 pm

    We should improve our reading habits above the level of junk.

  11. Broadlands permalink
    July 8, 2018 12:54 am

    “Up to 50 motorists were left with their tyres covered in bitumen that had melted on a stretch of road outside the Australian city of Cairns in northern Queensland.

    That’s where the Great Barrier Reef is located. While that urban heat was creating problems, the corals were underwater…away from all that CO2 induced warming.. that some decry as the cause of the Reef’s demise. When their widely publicized bleaching took place it was not “global warming”. It was clear sky UV radiation. Check out the literature. Gleason and Wellington.

  12. mary stewart permalink
    July 8, 2018 4:35 am

    I checked out weather and temperatures for Cairns and there were no abnormally hot days!!! I think this is a beat up. Perhaps the bitumen was new or faulty.!!!!!! Most of the east coast of Australia has been experiencing colder weather with cairns recording a record low temp in June.

    • mary stewart permalink
      July 8, 2018 5:38 am

      And guess what if you check the records for the melting bitumen event “Here’s something you probably haven’t seen before. Recent roadworks between Tarzali and Jaggan spelt disaster for a number of vehicles. The gravel did not settle in the tar and was swept aside until the first bit of sunlight today since our recent rainy days. The tar melted today and even this semi-trailer came to a sticky end.” Quote from the Tablelander.
      “Cr Paronella said a section of the road was repaired by a Main Roads contractor a week ago. There were initial problems when gravel failed to stick to the bitumen.

      “We started getting reports in the middle of last week from people getting stones and gravel flying up everywhere,” he said. “We helped with brooms to get the gravel off.”

      That was during a period of cold, wet weather.”

      • quaesoveritas permalink
        July 8, 2018 9:36 am

        Thanks, I thought there was something more to it than just heat.
        The usual low standard of journalism in “the Metro”, of the sort you expect from a free newspaper, but others seem to emphasize the heat too.

        “A melting road caused a sticky situation for unlucky motorists in northern Australia after their vehicles were left “drowning in tar” following a spell of unseasonably hot weather. ”

        “The incident has been blamed on a change in weather, and damage to the road after it was resealed last week. “

      • martinbrumby permalink
        July 8, 2018 11:01 am

        This is almost certainly ‘surface dressing’, where the surface of the road is ‘dressed’ by spraying with a ‘tar’ or bitumen binder and then gravel rolled into the binder.
        A cheap (and not very effective) method of re- surfacing.
        It is mainly notable because, once open for traffic, flying gravel is everywhere, even if ‘temporary speed limits’ are observed.
        A very common problem is that the grade of the bitumen needs to be controlled, depending on temperature amongst other things.
        And the proportions of binder to gravel is also important. If you imagine the gravel as being very roughly like little spheres and the optimum level of the binder to be somewhere around or above mid height of the gravel pieces, you don’t need to be a genius with calculus to work out that small increments in binder quantity can have significant effects on depth, leading either to loose gravel on a very thin layer of binder, or a sea of bitumen (especially in hot weather) with bits of submerged gravel in it.
        How tightly do you imagine the average contractor (let alone public works outfit) control this?

  13. July 8, 2018 9:14 am

    The headline is what matters. The facts? Not so much.

    Theresa May should appoint a Minister for Drought, Boris would be ideal. It would then rain and flooding would follow because the heavy rain will run off the dry earth, leading to “extreme flooding” due to “carbon” emissions”

    It worked in 1976, but we weren’t afraid of CO2 then:

    “In 1976, during Britain’s driest summer in over 200 years, he was made Minister for Drought (but nicknamed ‘Minister for Rain’). Howell was charged by the Prime Minister with the task of persuading the nation to use less water – and was even ordered by No. 10 to do a rain dance on behalf of the nation.

    The appointment provoked much public mirth, but in true Brummie style, the Lozells-born MP responded by inviting reporters to his home in Moseley where he revealed he was doing his bit to help water rationing by sharing baths with his wife, Brenda.

    Days later, heavy rainfall caused widespread flooding, and he was made Minister of Floods.

    Additionally, during the harsh winter of 1978–1979 he was appointed Minister for Snow.”

  14. Gamecock permalink
    July 8, 2018 12:22 pm

    A statistical trick. There are thousands of cities in the world. It should be expected that some will set records during a year. WaPo bizarrely expects there to be no records set. You need no more proof of MMGW being bogus than WaPo connecting some record highs with global warming. A ‘jump the shark’ stretch.

  15. Bob Koss permalink
    July 8, 2018 12:42 pm

    I see both Alaska and Hawaii have 100F for their maximum temperature record, yet those locations are more than 5200 km different in latitude.

    Might make an interesting trivia question.

  16. July 8, 2018 7:48 pm

    Reblogged this on WeatherAction News and commented:
    A perfect illustration for UHI is shown in this article from the Daily Mail on 26 June quoting the MetO;

    This comes after a warm night in the capital with those in London struggling to sleep with temperatures hovering around 64F (18C).

    [Marco Petagna – Media Advisor and Senior Operational Meteorologist with the UK Met Office] said it was much cooler out towards the countryside with lows of 48F (9C) recorded in Surrey and even down to 36F (2C) or 67f (3C) in Scotland and 45F (7C) in Exeter, Devon.

  17. Derek Colman permalink
    July 8, 2018 11:59 pm

    Not one mention in this article about the high number of locations experiencing unusual cold. BTW, the Scottish record high was from one weather station, which it transpired had an ice cream van parked beside it with the engine running all day to keep its fridge working. This series of heat waves is due to jet stream blocking patterns which correlate with low sunspot activity. It’s the Sun, stupid.

    • quaesoveritas permalink
      July 9, 2018 6:23 am

      Good point.

      Each month there are parts of the globe which have temperatures “above normal” and others which are others which are “below normal”.

      When we eventually see the figures for June, if there really are some areas which are considerable warmer than normal, there will be other areas

      which are considerably cooler than normal.

      Concentrating only on those areas which are warmer than normal, as proof of “global warming” is cognitive bias in the extreme.

  18. saparonia permalink
    July 9, 2018 1:05 am

    It’s been snowing in Wyoming!!!

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