When is the ideal time to contact potential PhD advisors?
Assuming you’re talking about the US, the summer would be a good time to start contacting faculty about your interest, although the exact amount of funding and the availability of open positions more than a year ahead of time is murky at best. So you’re not likely to get a commitment at this time, but you will make yourself known to the research group, which could be of benefit in getting an admissions offer.