Ticket prices change all the time and are very unpredictable. It is always advisable to purchase your air tickets as early as possible. Prices are likely to increase when airline tickets are purchased nearer to your travel dates.
However, using SkyScanner, you can sign up using your e-mail ID and get a price alert for the trip you selected. You will also be able to see the price of tickets for each date during that month by clicking “Show whole month” at the top left.
Another site you may use is Kayak. You may also sign up at this site to receive price alerts. In addition, this site has an “Our Advice” section. It will state whether if the prices are likely or unlikely to decrease within the next seven days.