I know that speakers move air to create sound waves, and that as speakers voice coils heat up certain sound charastics change. My question is does the tempreture on the day have much or any effect on SQ or is it more prone to affect low frequencys because they are moving more air (normally DB type installs however i know MAZ's system moves a fair amount of air through that nice square port, its lie being in front of a fan on intermitent...)

Also does humidity have any impact on how speakers respond on a certain day?

well there are lots of theories, but in regards to real world experience ive found that when speakers are cold (havent been used for a while) especially when the weather is cold ie during winter, the system sounds quite shallow, dry and brittle (lacks midbass and sounds too treble biased) for the first 5-10 minutes, and then after that normal sound returns. could just be that my brain has accusomed itself to music, or anything really, but thats what ive found it is a common practice amongst audiophiles to warm up an audio system before you seriously listen to it - voice coils, amplifiers, all these things are designed to perform when warm and not cold.

i've noticed this as well' my system always takes about 5-10 min's to sound really nice especially the subs on cold mornings, maybe because it takes a while for the suspention to loosen up but it is quite noticeible .
never really notice a lot of diference with the fronts i guess in theory they should sound better in colder wether' i think the biggest change is at night, i've even had people ask if i've re- tuned my eq's or "you finally got round to tunning your eqt's did you", when they've hear it at night compared to the day.

Temperature may have a small impact on the speakers suspension, but this obviously will mainly only effect the low frequencys significantly (ie around the speakers Fc) and not be audible. Port tuning also differs with temperature, but it won't be audible either.

The only easily audible change will be thermal power compression - when your speakers or amps are REALLY! hot (ie close to being blown) they have lower output etc, but obviously this is a change for the worse, rather than better.

I believe that humidity (at least in Australia) has significantly less effect than temperature..