Fleas are certainly more prevalent during warmer weather but they are around all the time and cats can get fleas any time of the year. I treat my cats throughout the year.
It is more to do with the temperature of their home environment (ie indoors, if they come indoors) than the time of year. The fleas breed like mad in warm conditions, so as Bensmum says, treat them all year around.
NB Flea collars don't really work any more - you will have to use something like Frontline to break the cycle (it's cheaper in the Pet Supermarkets or on line than in your vets btw)
cool thanks guys!, the last time I owned a cat it was flea collars or nothing, I am looking to get one in the future and Im delighted that there is an alternative
the cat used to give me evils when I got her collar on!
I prefer Frontline to flea collars. I used to have collars on them but the fur came off round their necks. I use Frontline during the summer when I notice them scratching more.