December to Febuary after 9pm.
1 bug in June. (Appears on tree stumps)
August to November after 8am. (Also 1 from 4pm to 7pm)
That should be it I think.
I'm on July right now and I don't want to jump around today. I think both of the tree stump beetles show up on the island if you have any stumps there, so you might want to try that. Can you tell me what August fish and bugs you need? They are probably also available in July, but I can check to make sure.
I'm looking for the following in August:
- Mosquito (5pm to 4am)
- Petaltail Dragonfly (4pm to 7pm)
- Rice Grasshopper (8am to 7pm)
- Walking Leaf (8am to 5pm)
The mosquito and walking leaf do not show up when your gate is open or you have visitors, so you'll have to time travel yourself or just wait if you want to get those.