The overnight low

A factor we often forget to take into consideration.

We check the forecast for the daily temperature, wind, and percent chance of rain. We check the time of the sunset and last light.

But the overnight low is often overlooked, and at times it is critical.

Have an autumn project that gets morning shade?

If the overnight low is 26 degrees, you might not get a chance to climb without numbing out until the sun hits the wall, in which case it might be best to choose plan B.

Or an unseasonably warm day in the forecast?

If the overnight low is reasonably cold you’ll have a longer window of good conditions before it gets too warm, and likely some wind as temperatures rise more quickly than usual.

The overnight low: not a necessity, but a piece of useful information when considering the best way to spend a precious climbing day.