Rock On, Hard On

“ Try this: Count the number of times a cricket chirps in 15 seconds, and add 37. No, you didn’t just calculate your age in cricket years - you measured the temperature outdoors in degrees Fahrenheit. You just used a rule of thumb. ” -

- rulesofthumb.org  

At first I thought this was a joke, but I’ve been assured that this indeed works.  Unfortunately, however, I live in a country where Celsius rules so that little cricket needs to start doing some .3 chirping before I can impress anyone with this trick.