In Japan we can watch fire flies on  in June first half. But the rainy season has set in so it's so difficult for us to meet see them. I will am going to look for them this weekend.

fire fly

In Japan, we can watch fire flies on during the first half of June first half. But However, (you can use but here too, but however sounds better) the rainy season has set in so it's so difficult for us to meet them. I will look for them this weekend.

fire fly Firefly

In Japan we can watch fire flies fireflies in the first half of on June first half. But now the rainy season has set in so it's so difficult for us to meet see (or "encounter") them. I will look for them this weekend.