A New Low

Three percent relative humidity!

This is the lowest I've ever recorded on my weather station (and I've had an electronic weather station going for five years now). The temperature outside is 89F, but you'd never know it — it feels more like about 80F or so with our more usual 10% to 20% relative humidity.

While the low relative humidity makes the heat more bearable, not all of its effects are good. For example, sustained low relative humidity (especially combined with wind) sucks all the moisture from the dead brush and other plant-derived fuels in the chapparal, greatly increasing the danger of wildfire. This phenomenon is why the fall has the greatest fire danger for us, as we generally have low relative humidity most of the summer.

But generally not quite this low! I was a little shocked to see that number on my gauge... BTW, the "37" you see on the gauge is the high value for relative humidity in the 24 hours preceding the snapshot I took showing the "3" reading. That 37% relative humidity occured in the middle of our night last night. Our air cools rapidly in our cloudless nights, and as it does the relative humidity goes up — usually to 100%. So even this "high" reading is quite low!