Suicune is now avaiable as limited time raid boss for the next 3 months. For the first month, from August 31 to September 30 he will be available in the Asia-Pacific Region. He will then switch regions on September 30 and October 31, so stay tuned to find out where he will appear next.
Tips and strategies
Effective attack types
As a Pure Water-type Suicune has only 2 weaknesses: Grass and Electric. Both are super effective against him, so use these attack types when fighting him. Conversely, avoid using Water, Ice, Steel and Fire type attacks against Suicune as he is resistant to those types.
All of Suicune's Charged attacks are Water-type, so Dragon, Grass and other Water-type Pokemon are a good choice when facing off against Suicune. Although, when choosing Water Pokemon make sure it's attack is at least Neutral vs Suicune.