Guest guest Posted August 17, 2006 Report Posted August 17, 2006 I wish the people who give the weather and temperature, would include the dew point. Where I live, they give the temperature in Fahrenheit, not in Celsius. But I don't think it would be so hard for the weather people to figure out the dew point, and it wouldn't take long for them to say it. I'd like to know it. > > Hey guys, > I found out that dewpoint is a better indicator of when you can put > the windows open (if your allergies permit), since it is more > indicative of humidity than relative humidity. I thought to look it > up when local weather person said we'd be comfortable for a few days > since the dewpoint is going to be around the upper 40s-low 50s, so > looked it up. As temperature goes up and down, dewpoint stays the > same. Dewpoints below 55 about are considered very dry for summer. > I'm a newby on subject so some information may be wrong. I don't > know about others, but letting fresh air into house really helps me > if it isn't humid. In general I read it's better to go by dewpoint > temperature than relative humidity since as temperatures go up and > down during day, relative humidity will continually be changing. > However if dewpoint is low, can count on more consistent dry feeling > even while temperatures go up and down. I wonder if there is any > place in country where dewpoints tend to be low. I imagine not > since they probably come and go with wind currents, but not sure. > > <http://en.wikipedia.org/wiki/Dew_point> > > <http://weathersavvy.com/Q-dew_point1.html> > > Here's one excerpt from accuweather: > > Dew point is simply the saturation point of the air, or the > temperature to which the air has to be cooled in order to get > condensation. It is really a true measure of how much water vapor is > in the air...the higher the dew point, the more water there is in > the air, and the lower the dew point, the drier the air mass is. In > the summer, dew point is an excellent tool to use in determining how > comfortable, or uncomfortable, it feels outside. Here is a general > summertime guideline for dew points... > Below 50: very dry > 50-59: comfortable > 60-64: moderately humid > 65-69: humid > 70-79: oppressive > 80 and above: steam bath! > Now you may be wondering...how does dew point relate to relative > humidity? Well, the relative humidity is dependent on the > temperature and the dew point. The closer together the dew point and > temperature are, the higher the relative humidity is. The farther > apart they are, the lower the relative humidity is. Here's an > example of what I mean, and also an illustration why the term > relative humidity does tell you anything about how comfortable or > uncomfortable it is outside. > Let's say we've got a very humid air mass in place, and the dew > point is 70. It's daybreak, and it's very murky outside...hazy, and > perhaps even foggy. The grass, car tops, etc. are all covered with > heavy dew. Let's say the temperature at that time is 70 degrees. > With a temperature of 70, and a dew point of 70, the air is > saturated, and the RELATIVE HUMIDITY at that time is 100%. The sun > comes up, burns off the fog and evaporates the dew. There is no > front coming through that day...no air mass change whatsoever. So, > the air mass will have basically the same amount of water vapor in > it all day long, i.e., the dew point will stay close to 70. Now with > the sun out, the air heats up, and the temperature rises. Let's say > the high temperature that day, around 4pm, is 90 degrees. At that > time, the hottest part of the day, the RELATIVE HUMIDITY is only > 50%!!! That doesn't tell the average person anything about how it > feels outside!!! > The dew point is a good tool to use all year long. In the winter > time, the lower the dew point, the drier the air mass is, and the > more likely precipitation will fall as snow, even if the temperature > initially is above freezing. That's because the air temperature will > cool as the precipitation initially evaporates. > The heat index is simply a combination of temperature and dew point, > and how it feels. When the dew point is relatively low...say in the > low 60s or lower, then the heat index is basically the temperature. > However, as it gets more humid (higher dew point), then it feels > hotter than the actual temperature. There really is something to the > expression... " it's not the heat but the humidity " . When the > temperature is quite hot, and the dew points are very high, the heat > index is extremely high. Sometimes the heat index can go into the > dangerous category of 110 degrees or more. > The Real Feel Temperature is something we developed in-house here at > AccuWeather. It takes into consideration other factors besides just > temperature and dew point. It factors in the time of day, the sun > angle, and amount of cloud cover, the winds or lack thereof, etc. > For example, a temperature of 90 and a dew point of 70 will feel > worse at noon or 1 pm with the sun high in the sky than it will at 5 > pm or 9 am. Also, a temperature of 90 and a dew point of 70 will > feel worse when it is dead calm than if there is a 15 mph wind > blowing. The same thing goes for 90/70 with bright sunshine vs. 50% > cloud cover. For all of these examples, the heat index will be > identical...no difference > whatsoever, since it is based solely on temperature and dew point. > The Real Feel Temperature, however, will be different for each > case. > I hope I answered your question. If so, please close out the > question and give me a rating. Thanks! > > Sincerely, > > Dave Dombek > Expert Senior Meteorologist > AccuWeather.com > Quote
Guest guest Posted August 17, 2006 Report Posted August 17, 2006 Yes, I think they could make room for the dewpoint, considering they take so much time trying to explain 'why' the weather is going to be this way or that, like " there is a high pressure zone coming in..blah, blah, blah " . I have to listen to weather report severals times since my mind takes mini-vacations during these explanations. Temperature here (in Ohio) is given in Fahrenheit also and dewpoint if figured out. You can go to accuweather.com and put in your zip code and get temperature including dewpoint. Put it is your favorites or make a link to it on your toolbar or could even make it your home page so you get the weather report every time you pull up a new window. --- deary333 <deary333@...> wrote: > I wish the people who give the weather and > temperature, would include > the dew point. Quote
Guest guest Posted August 18, 2006 Report Posted August 18, 2006 I have to listen for repeats of the weather also. By the time they get to the temperature and so on, my mind is elsewhere. It would not be a problem getting the dew point while I'm on the computer, but most of the time that I'm interested in the weather, I'm elsewhere. Why wouldn't they think the dew point is important? If they think we'll be confused, what about relative humidity? Do people really know what that is? I think many people think it's the same as the dew point. > > > I wish the people who give the weather and > > temperature, would include > > the dew point. > Quote
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