It's very hard to detect when a glider or aircraft enters into a cloud. But, this sensor appears to be inexpensive and could be adapted with a custom logger (match book size) and attached in the cockpit at World Championships:

Balloon-borne disposable radiometer for cloud detection

http://scitation.aip.org/content/aip...1063/1.3685252

Here's another article

https://www.dropbox.com/s/d1wb0jttcz...ction.pdf?dl=0

Suppose you built 10 matchbook boxes and 100 fake ones. They would be installed on all gliders, but you never know which one has the real one. Logging of temp, RH and solar radiation could be analyzed after the fact.

Maybe this is too complex even for a World Soaring Championship. But, if cloud flying became a problem in the future, this technique would be a good deterrent.

Walt Rogers WX