Why does the A/C in my 2000 Diamante kick off when I drive in heavy rain? In light rain, it may happen once.

When it rains heavily, it shuts off all the time. Air blows, but the "snowflake" icon blinks and no freon is there to cool it down.

I can turn it off, and on again....and it works fine for another mile or two, but always shuts off again.