When to Tweet is a free service that analyzes your Twitter followers, and tells you what is the best time to tweet so that most of your Twitter followers read your tweet. It analyzes your Twitter followers, and their latest tweets, and computes their awake time based on that. After that, it computes the best time at which most of your followers are awake, and gives you recommendation for the time at which you should tweet.
When to Tweet is quite simple to use. You just need to provide your Twitter handle to When to Tweet.
After that, it will check your followers. This is a bit time consuming process. So, once it is done, it will send you a reply on Twitter (using “@”). The reply will have a link that will tell you the best time to tweet, and that page will also contain a chart that shows pattern of your Twitter followers.
When to Tweet is quite a nice service to use if you have Twitter followers that are located in multiple geographies. Instead of sending tweets in your timezone, you can find the best time to tweet using this service, and then schedule tweets for that time.
The free version of When to Tweet analyzes your first 500 Twitter followers, and 200 tweets of each of them. There is a PRO version as well, that analyzes up to a million Twitter followers, and 1000 tweets of each.
Check out WhenToTweet.com.