Showalter Index Calculator

Areas of Showers and Thunderstorms to Start the Work Week

Areas of rain and thunderstorms are forecast Monday across the central and eastern states. Some mixed rain and snow is possible in the high Sierra Mountains. Heavy to excessive rain may bring flooding in the central Appalachians. Read More >

Showalter Index

Enter the temperatures that you would like:

What does my answer mean?

Showalter Index greater than 0: Stable, but weak convection possible for SI = 1-2 if strong lifting is present.
Showalter Index between 0 and -3: Moderately unstable.
Showalter Index between -4 and -6: Very Unstable.
Showalter Index between less than -6: Extremely Unstable.

Areas of Showers and Thunderstorms to Start the Work Week

Showalter Index

by Tim Brice and Todd Hall

Enter the temperatures that you would like:

What does my answer mean?

What is the formula for the Showatler Index?