Mine has been doing it lately too. Not everyday, but at least once a week. It doesn't matter if it's cold or warm outside or if I've even been outside. Do any of you get the burning sensation in your nose, like you do when you are going to sneeze? That's how mine starts, it then goes on for that whole day, just a watery drainage from my nose & down my throat, then by the next morning it is cleared up. I cannot figure out what triggers it. I do have allergies but have had them my whole life & it has just started this the past winter. Today I went shopping for groceries, everything was fine, was outside a bit after I got home & it was about 70 out. After I came in the house early this evening, it started again. I do have astelin spray from the ENT doc & also take benadryl when this starts, but it usually does not help. AFter I've slept, then usually it's gone the next day. It may happen once a week or more, there is no pattern to this. It's definitely weird & frustrating.