It is 12/20/15 and although this add-on has been discontinued for some time, I was able to keep it working until today, when FF 43 installed itself. Now it won't work.
I have tried quite a few of the other weather add-ons and I am surprised to say I have not found one that is even satisfactory, much less as good as this one is. 1-click weather allows a forecast of local weather on a daily basis at the end of your address bar, where it is always visible. Nothing else does that that I have found.
I sure do wish someone would either update this add-on to allow for the required signatures, or create a new add-on based on the screen layout (at the end of the address bar - on all the time) that this one has.
I think the new security features of Firefox are generally a step in the right direction, but the disabling of this particular add-on is a big loss.