As Click and Clack say, "doesn't anyone screen these calls?".
You are going to have to figure out somehow if it quits for lack of gas or spark.
When it quits, can you keep it running, or at least trying by giving it a shot of choke. If so, something, maybe water, is plugging your main jet.
If not, you probably have some dampness somewhere in the ignition system but don't ask me to explain why it would recover so quickly.
You may be able to verify this by connecting a spare plug to the plug wire as soon as it quits and check for spark immediately. Two people could do this faster than one.
By the way, silicone spray is my favorite ignition system waterproofer, just don't spray it on points.