Few Air Conditioners Inwards Seattle (And Western Washington): The Dry Out Facts
Today, 1 of my favorite Seattle Times writers (Gene Balk) had a fun story virtually the lack of air conditioners inwards Seattle. Turns out that our ownership of air conditioners is noteworthy: no major urban centre has less air conditioning per capita.
Much of the article is fine, noting our mild temperatures, proximity to water, as well as cooling at night...all of import factors inwards our minor air conditioning count.
But at that spot is an critical fact that he doesn't mention. Our depression humidities. Whenever it is hot around hither our air is dry. Which makes us far to a greater extent than comfortable.
The relative humidity of the air is critically of import for comfort because evaporation of effort is an enormously effective way to lose heat.
Humans are unique inwards our might to effort from our skin. No other mammal other than Equus caballus tin exercise as well as so effectively....and according to what I read, horses effort differently than us (mainly inwards their armpit area). Even our closest relatives (the slap-up apes) purpose some other mechanism...panting....as exercise our pets. With millions of effort glands as well as naked skin.....we are the superstars of sweat. And evaporation of H2O requires huge amounts of unloosen energy (heat), as well as so is an enormously effective cooling mechanism. So if a human has a large furnish of water, he or she tin grip really warm temperatures....but at that spot is a catch.
For sweating to live on effective the H2O must evaporate from our peel as well as that exclusively occurs when the relative humidity is below 100%. The drier the air, the amend nosotros tin evaporate as well as cool. So 85F as well as 35% relative humidity is far to a greater extent than comfortable than the same temperature as well as 95% relative humidity. The National Weather Service fifty-fifty has an equation to limited this, which they purpose for their "Heat Index" (see below)
The southeast U.S.A. is pitiful during the summer, non because they are crazy warm (it rarely gets higher upwards 100F there) precisely because the humidity is as well as so high. Why? Because the air had been over the warm Gulf of United Mexican States as well as the amount of H2O vapor air tin alternative upwards depends on temperature of the H2O as well as the side past times side air. And the Gulf is really warm (80s to 90F)
Here is Seattle, our summertime air is nearly e'er quite dry. Most of the time, our air is coming off the cool Pacific Ocean. That keeps the temperatures moderate, precisely likewise prevents the air from picking upwards a lot of moisture--since cool air, fifty-fifty if it is saturated, can't alternative upwards a lot.
The spot out 1 mensurate of wet content of the air is dew point, the temperature to which air must live on cooled at constant pressure level to gain saturation. Drier air has a lower dew point. Our summertime air typically has dew points inwards the lower 50s... over the eastern U.S.A. dew points inwards the 70s are common.
And when this relatively dry out (low dew point) air moves inland it warms, as well as the relative humidity plummets. Why? Because relative humidity is the ratio of the amount of H2O vapor inwards a book of air, divided past times the max. H2O vapor that book tin hold--and that depends on temperature. Warmer air tin agree to a greater extent than H2O vapor than cooler air. So warming air, allows it to agree more, which makes relative humidity plummet.
Our warmest temperatures...our existent oestrus waves... occur when air comes from the east. That is when nosotros croak into the mid-90s as well as more. But that air is really dry. First, at that spot isn't much of wet source eastward of the Cascades...the province is arid. And equally the air descends the Cascades, it warms past times compression, which causes the relative humidity to fall.
Enough theory, let's cheque out what happened the concluding 3 days on function past times of my department! (see plot below, fourth dimension increases to the right). The 3rd panel shows temperature (black line) as well as dew indicate (red line). Our dew indicate was really modest....around 50F...about the same temperature equally the sea offshore. Temperatures swings upwards as well as downward each day, amongst a dull overall ascension equally nosotros accept warmed.
But await at the 4th panel...relative humidity. Huge gyrations... really depression (about 30%)when it is hot later on inwards the afternoon , precisely 70-80% when the air temperature is lowest at nighttime (55-60F).
And the depression humidities accept some other benefit...they allow our nights to cool. Water vapor is the most strong greenhouse gas, which agency it traps as well as reradiates infrared energy....slowing downward the nighttime fourth dimension cooling. That is why deserts tin croak mutual frigidity at night, fifty-fifty when they are hot boxes during the day.
Want proof?...Here are the minimum temps concluding night. In some lowland locations temperatures dropped into the upper 40sF! Those folks needed a blanket.
So sweating is virtually e'er effective around here, different for those poor folks inwards the SE U.S. Just brand certain you lot remain hydrated. Don't effort enough? Take a mutual frigidity shower or run through a sprinkler. Influenza A virus subtype H5N1 wet tower inwards forepart of a fan tin cool things down. And air out your domicile or story at nighttime to forbid the house from progressively warming up.
Much of the article is fine, noting our mild temperatures, proximity to water, as well as cooling at night...all of import factors inwards our minor air conditioning count.
But at that spot is an critical fact that he doesn't mention. Our depression humidities. Whenever it is hot around hither our air is dry. Which makes us far to a greater extent than comfortable.
The relative humidity of the air is critically of import for comfort because evaporation of effort is an enormously effective way to lose heat.
Humans are unique inwards our might to effort from our skin. No other mammal other than Equus caballus tin exercise as well as so effectively....and according to what I read, horses effort differently than us (mainly inwards their armpit area). Even our closest relatives (the slap-up apes) purpose some other mechanism...panting....as exercise our pets. With millions of effort glands as well as naked skin.....we are the superstars of sweat. And evaporation of H2O requires huge amounts of unloosen energy (heat), as well as so is an enormously effective cooling mechanism. So if a human has a large furnish of water, he or she tin grip really warm temperatures....but at that spot is a catch.
For sweating to live on effective the H2O must evaporate from our peel as well as that exclusively occurs when the relative humidity is below 100%. The drier the air, the amend nosotros tin evaporate as well as cool. So 85F as well as 35% relative humidity is far to a greater extent than comfortable than the same temperature as well as 95% relative humidity. The National Weather Service fifty-fifty has an equation to limited this, which they purpose for their "Heat Index" (see below)
The southeast U.S.A. is pitiful during the summer, non because they are crazy warm (it rarely gets higher upwards 100F there) precisely because the humidity is as well as so high. Why? Because the air had been over the warm Gulf of United Mexican States as well as the amount of H2O vapor air tin alternative upwards depends on temperature of the H2O as well as the side past times side air. And the Gulf is really warm (80s to 90F)
Here is Seattle, our summertime air is nearly e'er quite dry. Most of the time, our air is coming off the cool Pacific Ocean. That keeps the temperatures moderate, precisely likewise prevents the air from picking upwards a lot of moisture--since cool air, fifty-fifty if it is saturated, can't alternative upwards a lot.
The spot out 1 mensurate of wet content of the air is dew point, the temperature to which air must live on cooled at constant pressure level to gain saturation. Drier air has a lower dew point. Our summertime air typically has dew points inwards the lower 50s... over the eastern U.S.A. dew points inwards the 70s are common.
 |
| Dogs pant, nosotros sweat |
Our warmest temperatures...our existent oestrus waves... occur when air comes from the east. That is when nosotros croak into the mid-90s as well as more. But that air is really dry. First, at that spot isn't much of wet source eastward of the Cascades...the province is arid. And equally the air descends the Cascades, it warms past times compression, which causes the relative humidity to fall.
Enough theory, let's cheque out what happened the concluding 3 days on function past times of my department! (see plot below, fourth dimension increases to the right). The 3rd panel shows temperature (black line) as well as dew indicate (red line). Our dew indicate was really modest....around 50F...about the same temperature equally the sea offshore. Temperatures swings upwards as well as downward each day, amongst a dull overall ascension equally nosotros accept warmed.
But await at the 4th panel...relative humidity. Huge gyrations... really depression (about 30%)when it is hot later on inwards the afternoon , precisely 70-80% when the air temperature is lowest at nighttime (55-60F).
Want proof?...Here are the minimum temps concluding night. In some lowland locations temperatures dropped into the upper 40sF! Those folks needed a blanket.
So sweating is virtually e'er effective around here, different for those poor folks inwards the SE U.S. Just brand certain you lot remain hydrated. Don't effort enough? Take a mutual frigidity shower or run through a sprinkler. Influenza A virus subtype H5N1 wet tower inwards forepart of a fan tin cool things down. And air out your domicile or story at nighttime to forbid the house from progressively warming up.
 |
| "The S is for SuperSweat" |
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