Predicting dew

[koputai]

Is there a way, by looking at the weather, that you can predict whether it's going to be a dewy night?
Last night I had a friend over who wants to buy a scope, and it was the most horrendous night for dew. There was so much moisture in the air that we gave up after not very long.

Cheers,
Jason.

[Starkler]

Many of the weather websites will give you the current dew point temperature. Its just a matter of if the temperature will drop to approach that dew point.

[Karlsson]

The spreadsheet attached gives dew point as a function of relative humidity and temperature, both of which can be measured easily. The yellow zone is dewpoints between 10° and 5° below the actual temperature, the green zone is 5° or less - in the green zone things usually get wet...

[Outbackmanyep]

I find it dewy if i have had rain recently and the sky is clear, warm days followed by cool late afternoons, or if the grass feels moist after the sun has set. Thats normally how i tell at home! Other times i notice that if its clear and there is a slight breeze then i get a high level fog, once it comes over it brings moisture with it!

[matt]

That's a handy spreadsheet, Karlsson.

Many thanks:thumbsup: