I know that areas on the coast are more humid, compared to inland areas, but the heat + humidity you see around the Persian Gulf is just insane. Why does it have the humidity levels of the equator when it’s above the tropic of Cancer?
I had always read and been told that in tropical and semitropical climates, the high humidity keeps the temperature from rising too high, so I’m not exactly sure how it is that these areas regularly experience temperatures over 100 degrees with ~50% humidity??
It’s currently 7% humidity in Riyadh, Saudi Arabia. It was never humid for the 3 years I was there. It was the perfect definition of “dry heat”
Riyadh. The place which is 500 miles inland from the Gulf?
Since Riyadh is no where near the Persian Gulf, that’s not a very responsive answer, is it?
The humidity in Doha, Qatar, as I type this (7:26 pm local to Doha) is 40%. Just north of there, in Dammam, Saudi Arabia, it’s 36%. Overnight, into the morning (always the most humid time), the humidity will increase to about 60%.
Now, for someone in, say, Florida, that’s not particularly humid (morning humidity in Orlando, Florida will be about 90-95%, for example).
But for an arid desert region, that’s pretty substantial.
HenryIX, where did you get the notion that humidity keeps a place from being hot? Florida (as already mentioned) often has temperatures that are quite high (upper 90s). The only real moderating influence on Florida’s temps is the fact it’s a peninsula in the middle of a huge, albeit ineffective because shallow, heat sink.
Doha and Dammam get hot dry winds from the nearby Great Arabian desert which are a moderating influence on humidity and increases heat.
Pakistani port of Gwadar on the mouth of the Gulf currently is 30C with 93% humidity.
Long answer short, its juts not latitude and altitude which define climate, its also distance from the Ocean and local geography.
yeah, sorry. I misread the question. my bad 
The division between the tropical and temperate climate zones isn’t permanently along the Tropic of Cancer … it moves north and south depending on season, turbulence and general air flow in the area … we can certainly find where this dividing line is on average … but at any given moment in time this division may be quite removed from the average location …
Why are places by the Persian Gulf so muggy?
Because of the Persian Gulf … and all the water that is evaporated there and if and only if the air flow is “on-shore” … blowing the high humidity air onto the land …
There’s nothing about high humidity that limits air temperature, if we dump enough energy in … however, if we’re limited on how much energy we can apply, then only some will be used to raise temperature and the rest to evaporate water … one bit of energy can only do one or the other …
The Persian Gulf is quite shallow for being an arm of the sea. It isn’t deep enough to have cold water below like in normal oceanography, and I bet in parts the hot sun warms it right down to the bottom. It’s almost entirely closed in by hot desert shores. It’s basically built as a wide natural sauna. If the coastlines are ringed with mountains or plateaus, that would strongly increase the sauna effect. Hot air will rise right out of it, but water vapor is heavier than N[sub]2[/sub] and O[sub]2[/sub], so I guess more of it is retained by the seashore. The Iranian side is all lined with mountains, but the Arabian side doesn’t have any except on the Musandam Peninsula by the Strait of Hormuz. The Persian Gulf littoral of Arabia rises very gradually to the uplands of Riyadh. Having mountains lining one side of the steaming Gulf must affect the winds a particular way, but I’ll leave that to the meteorologists.
I routinely see single-digit daytime humidity reported on WxUnderground for my current location in the summer, and I can see the Gulf from my 12th floor apartment windows. Current temp as I type this is 97F/43% humidity on WxUnderground. Today’s high temp was 111F, with a forecast 119*F later this week. Next month we will regularly see high temps in the 120s, if last summer is any indicator.
Conversely, when I used to deploy to the UAE with the Air Force, our air base would sometimes experience summertime humidity levels approaching 90% along with 100+*F temps, and we’d often have a late-night/early-morning fog layer dense enough to cause aircraft to hold for a couple hours, and sometimes divert to other bases.
Manama Airport in Bahrain is also very humid at night in the summer. Not quite as bad (with respect to the fog) as what I’d see in UAE, but still quite swampy.
Just depends what the winds are doing; if they’re blowing out of the desert, they’re kinda like a giant heat gun - hot as hell, but dry. Winds from offshore - not as hot, but swampy.
It’s not the triple-digit temperatures that’ll get ya, it’s the double digit humidity … 97ºF/43% … I’d be in the Persian Gulf …
Thank you. This was a very informative answer:)
Thank you. I don’t have the answers, just educated speculation going off of whatever I’ve retained from oceanography class. It just looks to me that if any seashore in the world was going to get freakishly humid, the Persian Gulf would have to be the prime candidate.
But the Adriatic is likewise a very shallow arm of the sea almost closed off at one end and with mountains lining both sides, and I’ve been to the Adriatic in the summer, but the humidity wasn’t noticeably high.
Yeah … I’m thinking the American Southwest … moist Gulf of Mexico air undercutting the Westerlies forced up by the Rockies … tornado country …
What makes you think that humidity has anything at all to do with latitude? Anywhere in the world that’s close to water will be humid, and anywhere that’s far from water will have low humidity. In Cleveland right now, the humidity is 61%, because we’re right next to a giant lake.
Depends on air flow … if the air is coming from above, it’ll be dry as a bone when it reaches the surface … like in Baja or the Atacama … not that it never gets muggy there, but on average not so much …
61% ??? … that’s inhuman … I’m suffering here in Eugene at 22% … July is normally much drier …
For that matter, what about the Gulf of California? Long and narrow, flanked all over by hot desert mountains. I don’t know because I’ve never been there. But if my hypothesis held, it would need to hold for places like Baja California & Sonora.
I just checked the weather for Kuwait. 6am, 90f, 84% humidity. My original assessment of it being the worst place on earth is intact.
The time I visited it was actually really quite pleasant. I had a nice afternoon walking about, and the weather was close to idyllic. Blue skies, cool enough to walk about without breaking a sweat, nice breeze. It doesn’t have much to recommend it as a tourist destination, there is only one industry, but the sea would make for some brilliant sailing, and the food was a very nice and interesting fusion. Kuwait’s location means it doesn’t receive the worst of the weather and humidity. But I was there at the best time of year. Othertimes and YMMV.
My understanding of the humidity problems is much as Johanna outlined. Sea surface temperature is a critical determinant of climate. And the gulf gets to warm bath levels. The energy in the water makes a huge difference in bridging the energy needs for vaporisation of water. The latent heat of vaporisation of water is remarkably high. Which is why you get significant cooling when you evaporate water (and is why evaporative air-conditioners work). If the sea surface is cool you can get some water to vaporise and it will cool the air (hence part of the reason “sea-breezes” can be so refreshing.) But if the water is warm it will give up water to vapour much easier, and any cooling effect will marginal. So you are left with hot humid air.
Good explanation, Francis Vaughan.
I just reread where I said water vapor must be heavier than N[sub]2[/sub] and O[sub]2[/sub] and realized that on the basis of molecular weight (18 vs. 28 and 32, respectively), that was an especially ridiculous thing to say, so I’m kind of disappointed nobody called me on it. (This must be why Cleveland summer humidity is worse on the Heights than down by the lake: warm water vapor rises. Clouds. Duh!) Anyway, like I said, I’m no meteorologist. I can tell you which rocks are likelier to sink below other rocks. Continental crystalline rock like granite floats on top of oceanic basalt like ice floats on water, partly immersed.
Another thing I can tell you is that the open ocean depths are filled with very cold water that has its own circulation currents, different from the warm surface currents, though in a kind of inverse relationship. Deep cold water upwelling brings up nutrients and oxygen from otherwise inaccessible depths in places where the deep currents meet the continental shelves + offshore winds. Places where this occurs, like the Grand Banks of Newfoundland (before they ruined it), have plentiful fish. Upwelling water has more oxygen (dissolves easier in cold water) and nutrients (from all the creatures higher up in the water column whose remains sank when they died).
It also helps moderate climate too, doesn’t it? Environment and life in the littoral by the open ocean depend greatly on warm and cold, surface and deep, ocean currents. Chronos, I remember the brutal summers in Cleveland all too well. Even on the Heights. If anything, summers on the Heights were even worse than when I lived down in the lacustrine plain of Cleveland city proper. This goes to show: Erie is very much the shallowest of the Great Lakes. If Lake Superior is the deep end of an Olympic swimming pool, Lake Erie is the puddle in somebody’s footprint.
Since the Persian Gulf hasn’t any of that cold water, at least in its shallower portions such as the gulf head around Kuwait and Abadan, it’s all warm surface. Not so much a sauna as like filling your bathtub with the hottest water and hanging out near it. When its waves splash onto hot desert rocks in the sun, that’s more like sauna.
If you’re inviting being called out … I guess I could oblige …
It’s a bit more complicated than just molecular weights … that would be true if the air was a mixture of O[sub]2[/sub]/N[sub]2[/sub] and water … for example mixing BB-sized chunks of gold and aluminum, give a little vibration, and the two materials quickly separate … and even that is only indirectly associated with molecular weight, as molecular weight is just one consideration for density …
The better model is a solution, with O[sub]2[/sub]/N[sub]2[/sub] as the solvent and water as the solute … if we put a sealed flask of moist air on the shelf, we’ll have to wait a god-awful long time before the water vapor rises to the top and the argon settles to the bottom … perhaps never because of Brownian motion … and that sealed flask on the shelf is a terrible model for the atmosphere, a churning turbulent mass with better than 2 x 10[sup]16[/sup] W of power moving through (yes, I used radius this time) …
The Atacama Desert in Chile would be a counter-example to your theory … there’s no trough of mountains for this to sit in … one side is the open ocean … also Omaha, NE … it gets quite muggy there and that’s flatland to make a flatlander weep … and no large bodies of water nearby either …
Yes, the oceans do moderate the rate of global warming, but they won’t stop it … we’ve make our bed at 400 ppm CO[sub]2[/sub], someday we will have to lie in the bed … fortunately, our teenage children really are smarter than us parents, so they’ll figure out what to do about it …
I apologize for not jumping you before … fellow countryman and all that …