I would not doubt it at all.  The cold makes arachnoiditis pain increase and so does humidity.  Air conditioners create both.  Trust me, I live in Alaska.  When it is cold I hurt.  When it is cold and then rains with the cold I am even worse and sometimes even bedridden due to it.  I have only been diagnosed with arachnoiditis since March 2008.  I have a Boston Scientific  internal stimulator.  The stimulator takes away about 50% of my pain and the meds only take away about another 25%.  But pain  levels are definitely affected by the barometric pressure and the cold.  Many doctor will say there is no evidence to prove that. I believe if they ever get arachnoiditis, they will have a different opinion on that issue.  Best wishes, Alaskan User.