Spring and Fall are both nice times to visit Japan weather wise, and developer events are normally happening during that time.
Doing a quick search, I think the only regular PHP event in Tokyo is in Japanese. There seems to be both bilingual and Japanese .NET events. There’s also a yearly PHP conference, the next one scheduled for December 2018 (though in past years it seems to also be an exclusively Japanese event).
One thing to consider is offering to give a presentation at a developer event. Speaking is a great way to quickly build up a local network. I think any of the events would be ok with an English presentation, as Japanese developers tend to be better at listening to English than speaking it.
I decided I’ll be visiting in the fall, considering mid to late November for about two weeks.
I appreciate the tip on speaking. Are there any activities/places to visit that would give a quick representation on what it’s like to live in Japan? I know when traveling it’s easy to do the touristy stuff and not get a true sense of what it’s like to live there, especially with only a two week period.
Hmm, that’s hard to say. As you mention, being here as a tourist is a fundamentally different experience. However, I think it will still give you a good sense of whether or not you’ll like being here. So my suggestion would be to just focus on having a good vacation here.