Weather Conditions Affecting Performance?

[port perran]

I've posted on a similar subject before but I am becoming increasingly convinced that weather and/or atmospheric conditions affect performance of locomotives/stock etc.
My layout ran faultlessly on Friday(and indeed generally runs extremely well) but in the very cool and extremely wet conditions today, running has been generally more juddery and minor derailments much more frequent.  The layout is in a front loft style bedroom but with reasonably significant temperature and (I think) humidity variations.
Does anyone else think that temperature/humidity significantly affects running ?

[EtchedPixels]

I've not noticed beyond the expected things - track with insufficient gaps buckling as boards shrink in the heat.