Is there a way to find out what raids are going to take place?

www gymhuntr .com has been trying in my city. However, not sure of their coverage in other places, plus even here it has gotten a bit sketchy in the past 36 hours

Silph Road had announced a "gym beacon" system, user shared, similar to their nest atlas. However I have no direct experience with it since there are several very active FB groups that I've joined since the raids started so get a lot of information that way. Hard as a solo player...

Facebook has been the safest bet here, and it's not been great. The Silph Road beacon looks like it would work great if they could get users. I try posting a beacon and sharing it all over to get the word out once a day, but I never get a response.

People in my local area started a group on discord. It works out great. We use multiple channels to break up the city into quadrants and post in the respective channel when a raid is spotted.

Actually there is a very efficient one, but is illegal, it calls gymhuntr, if you have reservations with trackers you won't be comfortable using it

https://gymhuntr.com

The most reliable is direct contact, there are many options including slack, groupme, Facebook. For the most part everyone needs help on Tier 4 and are looking for more players, so if you see someone at a raid talk to them, even if it's for a few min. I got added to some groups by random people I talked to on the street.