Does it make a differece whether it's dry heat or humid heat if the heat index temps are the same? (night, degree)
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How did the dew point increase by 31°F (17°C) in just two hours?
In any case, thank you for approving my system (I would rep you, but it says I need to spread some rep around), and this really does go to disprove the stereotype of it always being hot and dry in Phoenix, doesn't it?
Location: Live:Downtown Phoenix, AZ/Work:Greater Los Angeles, CA
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Quote:
Originally Posted by YITYNR
How did the dew point increase by 31°F (17°C) in just two hours?
In any case, thank you for approving my system (I would rep you, but it says I need to spread some rep around), and this really does go to disprove the stereotype of it always being hot and dry in Phoenix, doesn't it?
Different cities, that was the current condition for both Phoenix, AZ (Sky Harbor) and Houston, TX (Intercontinental). Observation was 4 Pacific Time/6 Central Time
Different cities, that was the current condition for both Phoenix, AZ (Sky Harbor) and Houston, TX (Intercontinental). Observation was 4 Pacific Time/6 Central Time
Whoops, didn't see that they were two different cities. Sorry about that!
The feel is different, because the humid heat index has humidity adding to the raw heat, whereas in the identical dry heat index it's just the raw heat. When you have an identical heat index, i.e. you feel the same level of heat in both places, you just go with whether you like the feel of low humidity or high humidity. I strongly prefer low humidity myself, so I'd go with the dry heat every time. I'd even go with it if the heat index was significantly hotter, since the humidity itself just makes me miserable.
In terms of standing in the shade, shade will have a far more noticeable cooling effect in dry heat than in humid heat. Wind will also feel better in a dry heat than in a humid heat, since when it's just humid you just get the humidity shoved in your face, whereas with dry heat you have air that feels purer; then again, there's the risk of the dry heat wind exerting a hairdryer effect, which if anything makes it feel hotter. That doesn't usually happen when the wind is only 5 or 10 mph, though.
I once tried very dry 51°C (123.8°F) with 65 km/h (39 mph) wind. It was horrible.
As others mentioned, the heat index is pretty much just a subjective made up number based on feel, and really only is useful for comparing weather in the same place from day to day.
I can tell you from experience that identical heat index numbers in two vastly different locations means diddly squat, such as your Miami and Phoenix examples. I'm from Michigan, have lived in Phoenix for 15 years, and have spent a considerable amount of time near Miami and up the eastern coast of Florida. I was recently in Jensen Beach, which is a couple hours north of Miami, back in January. Even then, the temps were in the 70s, and it just felt plain muggy and nasty compared to Phoenix.
Right now, the heat index in Florida is 79*, and it's 89* here in Arizona. It feels quite pleasant to me here at home, and I can tell just by looking at the other weather numbers in Florida that it would feel downright disgusting to me.
But then there are people that would think the current outside temp of 93*, especially at night, to be downright oppressive regardless of humidity or heat index. I'm the opposite - I think places like Florida are downright oppressive, regardless of temp, because of the humidity levels. There's NEVER a time that coastal Florida feels "good" or "comfortable" to me, whereas I'm plenty comfortable in Phoenix for 9-10 months out of the year.
Yes. At least in dry heat, it's cool in the shade. When it's humid, the shade isn't worth a crap. I've lived in both Florida and Oregon, so I can definitively say dry heat feels better. Take today: I live in Medford, Oregon. I just got back from a 45 minute walk. It's a bit on the hot side, 82 degrees, but there's a slight breeze blowing and it felt great in the shade, and I was barely sweating, so I felt okay. If it was 82 degrees in Tampa, being outside was misery.
Heat index and wind chill are a bunch of contrived drivel designed for people who don't understand how weather works. The correct answer is to use the entire pair of statistics (temp, wind speed) for cold conditions, or (temp, dew pt) for hot conditions. To answer your question: no, distinct pairs of values will not in general feel similar at all, even if those two pairs give the same heat index or wind chill value.
Location: Live:Downtown Phoenix, AZ/Work:Greater Los Angeles, CA
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Quote:
Originally Posted by Shalop
Heat index and wind chill are a bunch of contrived drivel designed for people who don't understand how weather works. The correct answer is to use the entire pair of statistics (temp, wind speed) for cold conditions, or (temp, dew pt) for hot conditions. To answer your question: no, distinct pairs of values will not in general feel similar at all, even if those two pairs give the same heat index or wind chill value.
HI and Wind Chill aren't telling you what it "feels like", they're telling you how effectively your body can cool itself (heat index) or how quickly your body will lose heat (wind chill)
HI and Wind Chill aren't telling you what it "feels like", they're telling you how effectively your body can cool itself (heat index) or how quickly your body will lose heat (wind chill)
I know that NWS claims that, but it's not how most people understand it. Also the NWS claim itself is arrogant; wind chill for example is based on a number of assumptions and simplifications about how fast a "typical adult person" with "normal skin tissue resistance" would get frostbite, but there's no one-size-fits-all answer like that. All these weird assumptions can be found on the NWS wind chill page, it's obvious that there's nothing physically intrinsic about it like the actual air temp.
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