I was wondering if anyone else finds that adsense seems to pay more per click in certain months. Not sure why, but winters and summers are always lower for me.
Not true, before christmas, valentines or fathers/mothers day your likely to earn more due to the step up in advertising from businesses for the holiday season sales and it will have a reverse affect after those holidays due to companies spending their advertising dollars for that holiday season.
this statement is true to a certain extent, Since the advertiser gets to bid on how much they pay it depends on the timing. Holidays will draw more as people will want to get there products and sites out. summer seasons may see more increase in vacation and summer related events and products same as winter. The main reason these look like increases basically is because the targeting is more relevant and in demand. If my site focuses on summer vacations and its the middle of winter as an advertiser my spending limit or ad words bids will be low. but when the summer comes around holidays like labor day the advertiser will spend more because its more likely that people will actually convert and pay for a package or have more interest. but do not thing that timing is the only reason you will see an increase your traffic at the time will be a factor in the matter. the more quality traffic you have will increase the cpc also. keep in mind that there are many factors that determine the price of the click not just the months. Study your niche and analytic and look at what the past results are and work with them.
At the time of year end like December, January month, adsense earning become low usually. My adsense earning decreases almost 60% than usual month.