Some forecasters will give the dew point temp. This is the temp. at which dew or condensation will form for the current temps and humidity.

 

Some forecasters will give the dew point temp. This is the temp. at which dew or condensation will form for the current temps and humidity.

To add to that, if you know the dew point temperature for a given night and also know that the air temperature is going lower than the dew point temperature that night, you will have dew on your bike the next morning.

Dew point = Temperature at which dew begins to condense out of the atmosphere. Generally, the lower the air temp below the dew point, the more dew will form.

 

The site I generally use, accuweather.com, also shows the hourly dew point forecast, but even when the dew point is well below the temperature (say 15 degrees difference), my bike still gets saturated. I'd expect there to be more and more condensation as the dropping temperature nears the dew point (i.e. not like a binary switch), but I guess I'm trying to understand what practical/mathematical combination of temperature, humidity, dew point, etc. means a wet bike is likely.

 

weather or not

Consider using a motorcycle cover.
I use an undersized one because it packs easier and it is used mainly to keep the suns rays and heat off my Burg.
Also, an undersized one is less likely to push a motorcycle over if it gets windy because of its smaller profile. A cover that goes over the windshield and hooks around the rear of the Burgman is just the ticket.
When you get ready to ride, reach under the cover to tap the beads into pools then tip the cover away from you to drain.
I use a small bungie cord to hold the cover onto the rear seat so its moistness doesn't affect my stuff down below.

If you're gentle, an inexpensive $20-$30 cover might do it.

 

I use NOAA

It Includes:
Temperature
Dewpoint
Wind Chill
Surface Wind
Sky Coverage
Precipitation Potential
Relative Humidity
Thunder
Rain
Snow
Freezing Rain
Sleet

In summer it includes
Heat Index

NO ads or pop-ups, and usually better than the rest.

Last week we had a lot of fog that did not play by the normal rules, at well below freezing. Obviously, anything that is at a lower temperature, than the humid air around it, will get wet. (or frost).

If a warm fog rolls in, the dew point can change quite quickly, and you will get wet.

Where are you from?

 

I do have a cover that I almost never use. It's easier for me to deal with a wet bike than a wet cover, that is when it's only condensation.

I do check NOAA and weatherunderground.com, though like accuweather.com for the hourly forecast.

I'm in So Cal, so have little to complain about relative to others here, but just want to be able to predict when to expect condensation.

 

I have thought, but havenot tried, about a simple spare tire cover for the seat. I have seen some seat covers here on the site but thought someone might try something different.

 

The one thing that is missing in this discussion is the temp. of the seat. What? you ask? Well, a black seat will have a different temp. than the surround air according to wheather or not there are clouds.

A black seat will radiate more heat and thus lower its temp. to a cloudless sky. With clouds the seat will be at the same temp. as the surrounding air.

Dew will form on a cooler object.

You should have more dew on the seat on cloudless nights. It is the same thing for frost on windshields of cars. There will be more frost on cloudless nights.

 

That's an interesting point. I'll use an infrared thermometer to check the temperature of the screen, seat, and trunk, which seem to be most susceptible to condensation, to check if there's any difference between this and air temperature.