Thermal strength
The climb you can realistically expect in a thermal.
Thermal strength is the climb a glider can realistically achieve in a good thermal: the rising air minus what the glider itself sinks while circling.
How to read it
Section titled “How to read it”The value is the climb on your vario, averaged over a good thermal, not the peak of a single gust. Move the hour slider to see when the thermals switch on, peak and fade.
What goes into it
Section titled “What goes into it”The strength of a thermal comes from how much heat the ground passes to the air and how deep the thermal layer is. Rain, heavy shading, strong wind and cold, wet ground all weaken it. See Thermals.
Because the glider’s own sink is taken off, the value depends on your glider and wing loading: a lighter, slower circling glider climbs a little better in the same air.
The point forecast shows the climb by height, so you can see where in the column the lift is best.