Talk:Heat index

message: This clause is confusing: thus there is an inverse relationship between maximum potential temperature and maximum potential relative humidity, therefore making, say, a simultaneous temperature of 120 °F (50 °C) and 90% relative humidity physically impossible. There cannot be an inverse relationship between two maximums. And it is not clear why the second part is proven by the first. I am not sure what this sentence is trying to accomplish, but if you do I urge you to rewrite it without the "relationship" language.  -- cmh 03:43, 27 May 2006 (UTC)
thread_title: Inverse relationship

message: I've added a disputed tag because I don't think heat index and humidex are the same thing. The NWS heat index is calculated with temperature and relative humidity, while the Environment Canada humidex is derived from temperature, dewpoint and vapor pressure (http://www.weatheroffice.ec.gc.ca/mainmenu/faq_e.html). -- Mwalcoff 01:37, 1 June 2006 (UTC)
replies: text: Side note on that: Relative Humidity can be calculated by using vapor pressure and a constant.  They could be basically the same thing going through slightly different math.
IMO this isn't a dispute, this is you not liking a sentence in the article. (A dispute is where two parties can't come to an agreement.) It makes no sense to tag this whole article as disputed just because you think "heat index and humidex" are not synonymous... the rest of the article is fine. I have reworded the first sentence to address your concern and removed the tag. In future, if you think something is wrong please simply edit the article to improve it, rather than putting dispute tags on things. -- cmh 03:00, 16 July 2006 (UTC)

text: I'm not a meteorologist and was hoping that experts could fix the article. I've removed the references to the humidex until this can be sorted out. -- Mwalcoff 03:05, 16 July 2006 (UTC)
thread_title:  Heat index = humidex? 

message: I can't tell what this means:
"...essentially the same temperature colder than which wind chill is thought to commence"
I'd fix it myself if I knew what the author was trying to say.
72.130.129.220 04:28, 24 July 2006 (UTC)
thread_title:  Confusing language 

message: I was just wondering if anyone had any information as to why heat index tables, such as the one on NOAA's webpage:  don't consider the result of high humidity at high temperatures.  For example, I'm currently in Qatar and the temperature is about 113F(45C) with a humidity of around 90%.  As I've read in some of the other comments, I'm sure some would say this isn't possible, but believe me it's true.  Using a seemingly unofficial online calculator at:  these values yield a heat index of: 272F(133C).  Realizing that even though it's really hot here, this isn't possible, why isn't the equation designed to consider extremes such as this?  Any information would be appreciated.
:: All I can say is, no, it's not possible.  Something is wrong with the humidity reading.  It may have been 90% humidity in the morning when the temperature was lower, but it won't be 90% humidity at mid-day because the amount of moisture in the air would have to increase drastically for that to occur, and that just doesn't happen in the real world.  Haplolology 19:40, 25 May 2007 (UTC)
thread_title:  Heat index at high temperature and humidity 

message: The article defines V, "vapour pressure", but doesn't specify the units to be used. ?mmHg ?mbar
:'Tis done ʍαμ$ʏ5043 17:33, 30 May 2007 (UTC)
thread_title:  Vapor Pressure Units 

message: I removed the hypothetical about Kent because the humidity was nowhere near 50% that day at the time the 101.3F was recorded.  If it had been, the dewpoint would have been about 80F.  In London, on the same day (8/10/2003), the dewpoint was in the low 40s Fahrenheit and when the temperature was 98.6F, yielding a relative humidity below 20% and a heat index of about 95F.  So, there's no reason to get into hypotheticals. Ufwuct 21:05, 25 October 2006 (UTC)
thread_title: Kent

message: All I want to say is that I would take any reading coming from Weather Underground very very cautiously, even if it looks correct.  I could give you a list of dozens of readings and long-term averages that anyone should be able to see are plainly wrong but which they list as officially correct.  In their defense, however, they have tagged many of the more unreliable stations as being "not official NWS values".  Haplolology 19:43, 25 May 2007 (UTC)
replies: text: I would definately agree with this, it appears that their local reading station gets fully exposed to sunlight in the mid afternoon resulting in it often reading 10 F higher than NWS / NOAA. Jon (talk) 14:35, 6 March 2009 (UTC)
thread_title:  Weather Underground 

message: Are the terms "heat index" or the colloquial "feels-like temperature" used otuside of the U.S.? -FZ 15:03, 12 July 2007 (UTC)
replies: text: Here in the UK, "feels like" values are occasionally given in winter, but that's about it. Our generally mild climate means that we hardly ever experience conditions where a precise wind chill/heat index value is really important. 86.132.142.207 (talk) 00:57, 28 July 2008 (UTC)
thread_title:  regionalism 

message: This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 09:53, 10 November 2007 (UTC)
thread_title:  WikiProject class rating

message: At least one of the formulas must be horribly wrong, as a simple check of the value for T=0, H=0 shows. The first says it's in Fahrenheit, but the second formula wouldn't make sense if it were in Celsius either, because -42.379°F just isn't anywhere near 16.923°C.  — Sebastian 21:57, 13 December 2008 (UTC)
replies: text: You might check to see if the formula(s) would make since if the temperature were in Kelven units as well since that is also a common unit by mathematicans. Jon (talk) 14:32, 6 March 2009 (UTC)
thread_title:  At least one formula is horribly wrong 

message: Heat Stroke and Sun Stroke are the same thing, both being Hyperthermia. Where essentially, the bodies ability to regulate it's own temperature becomes overwhelmed and fails. In the article it reads the following under Effects of heat index (shade value)
Danger — sunstroke, heat cramps, and heat exhaustion are likely; heat stroke is possible
I will correct this quote to correct the statement that implies that sunstroke occurs at one stage and heat stroke may be possible after. Medic48 (talk) 03:43, 12 May 2009 (UTC)
thread_title:  Heat Stroke versus Sun Stroke 

message: First of all, what range of dates or months does "summer" cover? Also, according to www.weatherbase.com, the average humidity for Phoenix in July is 24%, nowhere close to 10%. Also, Miami is at 67%, not 75%. The temperatures are more or less correct. If you run the calculations, Phoenix's heat index on a typical July afternoon would be several degrees higher than Miami.
A criticism of the heat index in general is that it assumes you are in the shade. This happens a lot less frequently in a place like Phoenix than Miami. Hence, the heat index makes Phoenix look a lot better than it should.
Kuvopolis (talk) 21:31, 17 July 2009 (UTC)
thread_title:  Miami/Phoenix comparison is inaccurate, heat index criticism 

message: I converted some degrees farenheit values to degrees celsius. I hope that relative heat can be converted. No formulae were provided for the original figures. See my IP's edits. --80.1.249.18 (talk) 18:47, 12 February 2010 (UTC)
thread_title:  Conversion 

message: This whole heat index concept is only a crude approximation, so to calculate more than even a few terms is specious.
187.132.3.243 (talk) 20:42, 10 March 2010 (UTC)
thread_title:  Formulae: 16 term polynomial? 

message: "The heat index is calculated only if the actual temperature is above 27 °C (80 °F), dew point temperatures greater than 12 °C (54 °F), and relative humidities higher than 40%[4]."
This statement is contradicted by NOAA:
http://www.crh.noaa.gov/jkl/?n=heat_index_calculator
NOAA says DP should be 60F  —Preceding unsigned comment added by PeterK2003 (talk • contribs) 22:51, 6 April 2010 (UTC)
thread_title:  When  HI should be calculated. 

message: The heat in Finnish sauna is from 60-100 C. Take if from me, I've lived in Finland for almost four decades and we sure don't go into sauna before it's at least 60 C, preferably 80 C. 100 C is uncomfortable to most people.
So please fix that part of the article. I'd do it myself, but can't comment on the actual heat index, because I know so little about it.
Please not that I only talk about temperatures in the above, not heat index.
—Preceding unsigned comment added by SuurMyy (talk • contribs) 17:09, 11 July 2010 (UTC)
replies: text: Definitely. Sauna temperatures are usually around 70...140 °C, humidities  5..30%. If someone finds an extension of Heat index to cover this range it could be reported here. Relative humidity of 100% and a temperature of 38 °C would make it a Roman caldarium. Turkish hammam is slightly less humid, but changing the heading "Turkish bath example" would be close enough.
128.214.182.212 (talk) 07:54, 1 August 2010 (UTC)
thread_title:  Finnish Sauna Example is Incorrect 

message: The last formula given, the simple one that gives a very rough approximation, is either incorrectly stated, or the example usage is wrong.  The formula given is HI = 1.9 * T * R + 10. The example uses T=90 and R=73% and gives a result of 124 F.  The only way to wrench that result from the formula is to treat R as a fraction (it was defined as expressed in percent in the prior two formulas) AND to ignore the constant 10.  Should the formula say R/100 rather than R?  Should the example result be 134?  Since I'm a reader of this article, not an expert, I can't correct it, especially since the link given twice in the article to the site that details the various formulae is broken (http://www.crh.noaa.gov/jkl/?n=heat_index_calculator).  So I can't even check if the experts there give the correct version of the formula (in which case I'd do the edit myself).  Could someone knowledgeable please fix the link and the formula?  —Preceding unsigned comment added by Paulalancaster (talk • contribs) 22:42, 12 August 2010 (UTC)
replies: text: I found an online heat index calculator elsewhere on NOAA's site: http://www.wpc.ncep.noaa.gov/html/heatindex.shtml.  If someone is interested, they could parse the Javascript source to determine the equation.  These two links (http://www.srh.noaa.gov/bmx/tables/hindex.html and http://www.srh.noaa.gov/ffc/html/studies/ta_htindx.PDF) found at the bottom of http://www.crh.noaa.gov/pub/heat.php seem useful, but they are also dead, unfortunately. Vidalian Tears (talk) 19:14, 26 August 2010 (UTC)
thread_title:  Incorrect example of formula and a broken link 

message: I found the following discussion of the heating and cooling effect of wind on HI.
-- which I leave here for others more-better than I.
http://www.zunis.org/at_least_theres_a_breeze.htm
  HalFonts (talk) 21:18, 17 June 2011 (UTC)
thread_title:  Wind vs Heat index 

message: There is a loooong formula for calculating HI, but no examples.  For the common user, this formula (using lots of  extended small values) in effect means that the article is a dead-end in terms of getting actual HI values. How about a table with  some values? Kdammers (talk) 00:44, 31 July 2011 (UTC)
replies: text: Done! Thanks for the suggestion.  Duoduoduo (talk) 16:17, 31 July 2011 (UTC)
replies: text: Great!  That really helps. Kdammers (talk) 05:21, 1 August 2011 (UTC)
thread_title: Examples needed

message: In this Wikipedia Heat Index article it states:
"The humidex differs from the heat index in using the relative humidity rather than the dew point."
In the Wikipedia Humidex article the same sentence is the opposite: 
"Humidex differs from the heat index used in the United States in being derived from the dew point rather than the relative humidity."
Both can not be correct.
I'm no expert, so I made no changes. One needs fixin. (22Dec2011)
HalFonts (talk) 05:22, 23 December 2011 (UTC)
thread_title:  Function of (dew-point or relative-humidity) -- HI vs Humidex Wikipedia articles 

message: Just below the first HI formula is the phrase "R = relative humidity (decimal fraction of 1.00, i.e. percentage/100)".  I can't get results from this formula to come out anywhere close to the NOAA table shown in the article, unless I use "R" values scaled as percentages (i.e. 0-100).  Then the results match within +/- 1 degree F, as far as I have checked.  I also confirmed the table's results match this online calculator: http://www.wpc.ncep.noaa.gov/html/heatindex.shtml .
Reference #8 (http://www.srh.noaa.gov/images/ffc/pdf/ta_htindx.PDF, at the bottom of pg. 2, states "R = relative humidity (integer percentage)."
I didn't look into the scaling of "R" in the second formula (with the 16 terms.)
BBmex (talk) 20:07, 16 February 2013 (UTC)
thread_title:  Scaling error of "R" in first formula 

message: I'm not well in English, but I think its wrong to say: „...resulting in a heat index of 78C (172F). This is comparable to the temperatures that are recommended to kill bacteria in many meat products, and it is common in a sauna.“
78 C could be the Temperature in a mild Sauna but the Heat Index in a Sauna is much higher because of the high Humidity. I'm also sure, that 42 C and a extreme high Humidity won't kill bacteria secure in meat products.--88.84.8.236 (talk) 00:14, 2 July 2015 (UTC)
thread_title:  Heat Index is mixed up whit Temperature 

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thread_title:  External links modified 

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thread_title:  External links modified 

message: The "History" section states
:the heat index uses heat balance equations which account for many variables other than vapor pressure
while the "Definition" section states
:The heat index and its counterpart the humidex both take into account only two variables, shade temperature and atmospheric moisture
These appear to me as a reader to be in direct contradiction, but I don't have the knowledge to alter either of the statements. Paleolith (talk) 17:50, 27 August 2023 (UTC)
thread_title:  Variables? 

message: Someone who has the skill should take a look at the NOAA table of values on a mobile display and try to fix it. The table is only partially visible and cannot be scrolled vertically. It is also confined to a tiny box instead of taking up available real estate. 59.180.144.103 (talk) 06:00, 29 May 2024 (UTC)
thread_title:  Table mobile formatting broken