Green tea contains caffeine, so it's best not to consume it too close to bedtime, but other than that, any time is great for green tea. The caffeine content of green tea can very fairly widely.
My personal experience is that I tend to avoid heavily-caffeinated green teas for about 7 hours before bedtime, and I avoid more mildly-caffeinated green teas for about 4 hours before bedtime.
My personal experience is that I tend to avoid heavily-caffeinated green teas for about 7 hours before bedtime, and I avoid more mildly-caffeinated green teas for about 4 hours before bedtime.
