Sommer is not good for the development. Many people continue to monitor cryptocurrency market even when market will fall. Fall of the market is the best time for searching new opportunities.
There is not a good time for development or bad time. It is necessary to continue to develop the project in all the times. Only the such cases the project will be able to survive.
Some experts predict that the rise of the market will start in August. So may be the August is the best time for token sale.