hmm.

try and keep your room/ area summary as possible.

keep it warm... play summary tunes, do things you'd usually do at a certain time in the summer- for example for me, 1 of the things i like doing is to post on my local theme parks forum (the theme park only is open in the summertime). though i've never been their myself, posting to it when it's closed makes me feel i'm their.. sun beating down on me, etc

hope this helps (probably not, but. )