Depends on the frequency. Clouds are famously transparent for ultraviolet for instance. The sun floods the sky with it of course, but there's plenty of choice. But at the ranges we're talking about 10-20, maybe 100km ... yeah pretty much unjammable by clouds. Sufficiently intense rain or something like a snow storm would probably work though.

I doubt you'd be flying in the conditions that would block a laser from hitting it's target. In practice, there really aren't that many ways to "jam" a rocket, radio jamming really can't hit all the bands, and frequency-hopping SDR is very, very cheap now.

To my mind your best hope would be an EMP or a small missile-tracking gun.

> frequency-hopping SDR is very, very cheap now.

Which also makes broadband frequency-hopping jammers similarly cheap.

Frequency hopping doesn't make jammers more effective. So long as you cannot prevent the pattern of the transmitter, your only option is to jam all frequencies, which means you have a massive disadvantage in the power you need to emit, to the point that simple directional antennas probably make your task flatly impossible.

Laser communications are being studied because they are impossible to detect, not because the existing communications are too easy to jam.

(late edit:)

*predict