A thread on WebmasterWorld reports about a new AdWords feature called "Timeframe", located under Budget Options, confirmed from Google. Timeframe gives advertisers a new budgeting method that automatically adjusts the daily budget based on your traffic to reach a set dollar budget as per the calendar month. For example, with daily budget, you might not use up the whole day’s budget and what is not used, is never used. But with the monthly budget, Google would automatically adjust your daily budget based on the unused monthly budget limit - which would then help you use your whole budget.

Source:→ SEL