North Sea "Smeg", which I've experienced nearly all of my flying career, is nothing more than a challenging weather phenomenon to visual and IR sensors. So, in the absence of a clear IR picture of what's out there you have EW and Radar to contribute (both off board and onboard).
The point is this - if something can target you in both the IR band and FOV of DAS you must assume it has LOS (pretty much), therefore the point (yet again) is moot - i.e. if it can't see you due to weather it can't target you so you win! EO-DAS is more than just a spectral contributor to SA, like all other sensors in the F-35. I can't say how good it is performing on a public forum but suffice it to say "it's impressive!" Please, shoot me down with your wise words of doubt if that's your deep-rooted agenda. Quote some public release saying EO-DAS is awful; I care not. Whatever folks. That sort of impression isn't representative of the truth; not by any stretch or clear margin of truth. Sorry but it isn't and i'm stating that for the record. No Kool-Aid, no BS.
Bottom line to the question presented - if you have a problem seeing something in the IR band through cloud then the enemy has the same (if not worse) issues seeing/targeting you. This assumes no radar, no cueing, no "other means."