I think I can comment on the weather in Berlin. I am not sure about the other place but I assume it won't be that different.
In Berlin, it is hard to say what weather it will be ahead of time. June is usually a pleasant month (at least for me, used to this climate), with temperatures between 15 and 25 degrees Celsius. The lower end usually requires jackets and the higher end is more t-shirt and shorts weather. In my experience, 25 degrees Celsius here feels very different to in a warmer climate. It has to do with the humidity. Long clothes feel unbearable with 25 degrees.
Rain is slightly less common in this month than in the other months, but you're likely to encounter some. Temperatures drop a lot during rain (in June till around 15 degrees Celsius). Being from such a tropical country, you may find the rain unpleasantly cold. Berlin is a city, which makes the temperatures slightly (1-2 degrees) higher than outside the city. The temperature difference is hardly noticeable, but the extra rain this causes is.
My advice is to pack layered clothes, as the weather can change during the day as well. Layered clothes are very flexible too. If it is hot all the time, you'll leave off your jackets bit if not, you just wear them. You'd do well to take some rain clothes as well, like an umbrella (if you don't have one, many shops in Germany sell some).