I think the only way to know for sure is to maintain a gear spreadsheet with specific (and yes accurate) weights.

I tweak such a spreadsheet for every hike, pack according to the list, and then weigh the aggregate on a hanging scale and always find the result within a quarter pound or so of the sum of the listed weights.

That sounds pretty geeky/obsessive, but it really doesn't take all that much time now, and I never ever find on-trail that I've forgotten something, and I've also gotten better and faster about making gear functionality/safety/weight trade-offs in planning a trip.

Electronics certainly can be a factor. Food should not be if talking about base weight. I find variations in all of the categories on a per-trip basis. Anticipated colder, wetter, and/or more buggy conditions all impact the shelter, sleeping system, and clothing choices. Hiking with a group vs. hiking solo or with others who have the same 'style' ditto. Cooking or going stoveless impact baseweight as well as total weight. Base camping vs. going for more daily distance too. Hiking in significant snow could add microspikes and/or a light ice axe (or self-arrest pole, which latter is part of skin-out but not base weight).

I think my base weight varies on a per-trip basis from about 12 to 17 pounds depending on all of these factors. Probably even higher yet if I do any snow-intensive trips with groups.