How many Bitcoins can I generate per day as a rough estimate for June 2015?
June is already over.
With an Antminer S5 operating 24 hours per day at the current difficulty right now you can expect to generate approximately 0.01175776 BTC per day.
You'll need to subtract from that any fees that your chosen mining pool collects. You'll also want to consider how much you'll spend on electricity to run the S5 as well as show much you'll spend on cooling and maintenance.
If difficulty increases in the future, you can expect the amount of bitcoins that you generate per day to decrease.