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Comment by ks2048 | Hacker News Reader

ks2048

I know there's a lot of reasons for this, but I think weather is one of the biggest. I wonder if that ever reverses from extreme heat. Is a full month of 110+ degrees having people reconsider Arizona?

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Air conditioning changed everything: https://www.energy.gov/articles/history-air-conditioning

> Engineer Henry Galson went on to develop a more compact, inexpensive version of the window air conditioner and set up production lines for several manufacturers. By 1947, 43,000 of these systems were sold -- and, for the first time, homeowners could enjoy air conditioning without having to make expensive upgrades.

> By the late 1960s, most new homes had central air conditioning, and window air conditioners were more affordable than ever, fueling population growth in hot-weather states like Arizona and Florida. Air conditioning is now in nearly 100 million American homes, representing 87 percent of all households, according to the Energy Information Administration.

Dewpoint and relative humidity are huge factors in how temperature is felt. 110F in Arizona might still feel more comfortable than 90F in eastern regions.

https://en.wikipedia.org/wiki/100th_meridian_west

>In the United States, this meridian roughly marks the boundary between the semi-arid climate in the west and the humid continental and humid subtropical climates in the east and is used as shorthand to refer to that arid-humid boundary.

I don't know. I was just in Northwest Arkansas with 100°F and 99% humidity and then a day later in Phoenix Arizona with 100°F and ≈30% humidity (at midnight!) and it felt similarly oppressive...

> Northwest Arkansas with 100°F and 99% humidity

People like to throw numbers like 90°F at 90%+ humidity. It doesn't work like this. If you look at the hourly data for Bentonville, AR (Northwest Arkansas) on the hottest day of the month [1] you see that by the time temperature got to 101°F humidity was at 32%. It is sticky as hell, but I guess as a number 30% doesn't sound impressive enough.

[1] https://www.wunderground.com/history/daily/us/ar/bentonville...

100°F and 99% humidity is a dew point of 100. The highest recorded dew point ever on earth is 95.

No, I do not believe that you were just in Northwest Arkansas with 100°F and 99% humidity.

I always feel hotter with the low humidity. It's stickier and possibly more uncomfortable if you aren't used to it with high humidity. But even low 90s with very low humidity feels like inside an oven to me. I was working outside all day yesterday and it was about 95 with with 60-70% humidity and it felt great with a slight breeze.

You were dehydrated.

A recent Atlantic article says, no. The county where Phoenix is, is still the fastest growing county in the USA, for multiple years running.

Most of the year the weather is good, apparently. Throw in air conditioning de rigeur, and cheap housing (due to no artificial supply restriction), and I guess you have the formula for population growth. Perhaps some politics are part of it too. Total taxes are half that of California. Probably not the #1 tax friendly state, but certainly up there.

Do we need a contemporary reason for it? People have been migrating away from the northeast since the early 1800s, and that is still going on today.

I went the opposite direction of that line several years ago. It's been high 70's and low 80's all summer. Two low 90 days so far.

Last winter was mild as well.

So yeah, that could happen. Lots of water here as well.

Arizona is tax friendly to retirees allowing a more comfortable living on a fixed income. That can pay for a lot of air conditioning (or swamp coolers).

People are way more tolerant of extreme heat compared to cold

Yes...up to a point. And there's the similar/related issue of extreme drought. If the wells and pipes run dry, the local population density tends to plummet.

Which is an artifact of a past age and foolish to bank on. Cold can be dangerous but we basically have what we need to survive at any low temperature in North America.

However, heat can't be combatted when you're outside in it with the same effectiveness. It reaches a point where the air temperature is simply lethal. It reaches a point where the paved ground burns whatever touches it. It degrades our medicines and damages our tools. We've already begun to experience these effects and it will only ever get worse. People should be moving away from hot areas, but instead they're running their AC 24/7 so they can keep pretending they made a good choice a little longer.

Until you get to wet bulb saturation extremes, you can survive heat as long as you have a supply of water. Cold temperatures, on the other hand, will kill you straight up.

Also, AC uses way less carbon than heat.

Heat pumps can work both ways.

We could reverse this statement, but replace "water" with "warm clothing". It's not like we haven't been ameliorating the effects of cold for ages.

> you can survive heat as long as you have a supply of water

Above ~55C (131F) that water will burn your tongue and throat. Even at 45C water will be uncomfortably warm.

What are you talking about?

A majority of the world's population is into drinking tea and other beverages significantly hotter than 55C

No, you're saying that like those extreme highs are distant specters. They already happen and are part of our immediate future. At which point, the human body cannot survive by evaporating water. Drinking cold water is an active measure which frankly is not available to all people, especially many of those most vulnerable to these fatal temperatures. When the WBT passes a certain level it will kill you straight up. Cold, not so much. People live in Antarctica. And although we will get storms and more extreme weather, the planet is getting hotter.

>> we basically have what we need to survive at any low temperature in North America

Senior citizens don't have what they need to survive shoveling snow at any temperature in North America.

Really cold seasons are cold around the clock... in the neotropical summer many people do go out running between 5AM and 7AM because it's fine to be outside when it's 75°-85°F outside.

At subtropical latitudes a low elevation desert climate with high temperatures overnight is very much the exception, not the rule. Likewise, it's unusual to have cold bright sunny seasons because few of us live in the Andes:

The hot subtropics are often bright even when it's muggy. This 24/7 makes one (even without going out jogging) feel less cooped up inside than the double whammy of low annual insolation gloom in so many cold latitudes when it's cold (even without having to walk in nor shovel snow).

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