Could be it…

The days of riding to work in shorts, no socks or gloves could be at an end. This week has seen some cooler weather and on a couple of mornings, I’ve been able to see my breath in the air. Now that doesn’t mean it’s necessarily baltic outside, because it’s to do with the humidity too.

We always breath out water vapor along with air, but can’t usually see it because the water molecules are not close enough to form individual droplets. Individual droplets can be seen at the dewpoint which is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current air temperature. If the relative humidity is 100%, the dew point is equal to the current temperature.

Now cool air can hold less moisture, which is why dew forms on the ground overnight, when the air cools. If it’s humid, you’ll be able to see your breath at higher temps, than when it’s less humid when it’ll take cooler temps to be able to see your breath. This is why you can see your breath in the winter much more easily than in the summer.

It’s been cool and dry over the last week – well up until earlier today, so it’s probably time to dig out the 3/4 bibs and long sleeved merino. Oh and bike lights… I’ll be needing them too.