Listen, i've been in this game long enough to know how Apple works when it comes to launches. And they do NOT always announce the new device a long time in advance, the product announcement is generally within a few weeks of the launch; if not the same day. With iPhones, it's generally the within a few weeks scenario. You may be confused due to the original iPhone, which was announced over 6 months before it shipped; but that was because it was a whole new product line for Apple, and not just a refresh of an existing product.
Let's look at the announcement/launch trends:
iPhone - announced 1/9/07; launched 6/29/07
iPhone 3g - announced 6/9/08; launched 7/11/08
iPhone 3gs - announced 6/8/09; launched 6/19/09
iPhone 4 - announced 6/7/10; lanunched 6/24/10
Notice only the original was announced more than 32 days ahead of launch. In the case of the 3GS; only 11 days elapsed. And only 3/4 of them launched in June, the 3g launched in July. So you can't even count on the month. Just because there seems to be somewhat of a trend with past releases, you cannot count on the exact same cycle everytime. Sometimes things just aren't ready. This is common in the tech world. However, you will notice there has been a refresh during every calendar year. I do not have any reason to believe differently this time around.
And yes, I get my information from things I read on the internet. No, not necessarily things I read on forums. Also based on things I read from such sources as The Wall Street Journal. Of course, I suppose I should just ignore all of those respected sources, and instead listen to a random person on the internet who is speculating without even understanding how Apple generally does things. Because I am so sure you are 100% correct in your thinking.