can someone help me interpret something on Weather Underground?

[ima_sinnic]

I feel foolish asking this: under "5-Day Forecast" for tomorrow, say, it shows temperature "47/38" --
I always thought that meant maximum and minimum, but when I look at "Hourly," it shows the temp going no colder than 45, and "dew point" actually going to 34 (i.e., "45/34" at 2 a.m.).

I understand that "dew point" is the temp at which "dew" or moisture comes out of the air, but how does it relate to the forecasted temperature? Is the temperature actually going to 34? I just don't understand "temperature" being shown along with "dew point"--if the temp is 45, when does 34 come into play?

:blush:

[slackmaster]

1. Dew point gives you an indication of relative humidity - lower is drier

It's also known as the "wet bulb" temperature.

[ima_sinnic]

2. ok, so it's not actually going down to 34 -- ?

thanks for the info

[slackmaster]

4. It means that if it DID go down to 34, things would get wet

Stay warm and dry!

[old mark]

3. If the dew point equals the actual temperature, the air is completely saturated

with water. The closer the dew point is to the actual temp, the more humid-and uncomfortable and hard to breathe-the outside air feels.
The dew point is actually the temperature at which water vapor ambient in the air condenses to form "dew".

I live in PA, and we generally have horrible humidity much of the summer, and it should be starting soon...

mark

[ima_sinnic]

7. ok, I guess I get it

just read Wikipedia on it and see it's for reference about humidity and not an indication of actual air temperature.

http://en.wikipedia.org/wiki/Dew_point

am concerned because, with global warming/climate change and unseasonably warm temps for most of the past month, I've taken a chance and planted some things almost a month earlier than normal here in Maine.

[old mark]

10. Yeah - our fig tree had HUNDREDS of small fruits 2 weeks ago, and

90% died off after 2 nights of frost last week - we still have aboug 50 or so, and there are new ones starting again...near 80 for several days now, going to low 60's on Sunday through Wednesday...welcome to the changing climate that people say does not exist...
We planted a lot very early, covered them with plastic bags for the frost nights - they all came through just fine - we already have pumpkin and cantaloupe plants growing, and small green tomatos and peppers-at least a month early.

mark

[Duer 157099]

5. I'm not sure about this but

on the 5-day page, the A/B seems to indicate as you say, the high/low.

On the hourly page, the C/D seems to indicate temperature/dew point.

So, they are showing different things, but both use the "/" -- is that what you're asking?

Like I say... I'm not sure, but that's my best guess.

[ima_sinnic]

8. I wondered what "dew point" had to do with temps

I'm not sure if "/" is showing temps or temp/dew point on the 5-day page either. "Hourly" certainly does not show temps going below 45 tomorrow in this part of Maine (it's going to be a crappy, cold rainy day, apparently, with high of 47).

[Duer 157099]

11. I know what you mean

It's as if the data for the 5-day and the hourly are coming from different sources (and perhaps that's true).

On the 5-day page, the two numbers are red and blue, whereas on the hourly, they are red and green, so I believe they are not showing the same thing.

[Oregone]

6. Well, its definitely illegal to bomb public buildings, despite the temperature

[ima_sinnic]

9. heh, can't believe I'd forgotten about THAT "weather underground"

duh ... :+

[whyverne]

12. Yeah, they don't match up exactly, but they shouldn't be

that far off. Are you sure you clicked on the right hourly? if you want the low temp for Saturday night, you gotta hit Sunday's hourly and look at the early AM temps.

I love Weather Underground. About the same as Democratic Underground.