Technical Abstract: Previous research at this location has shown that, on average, about 90% of our perennial grass production is completed by July 1, but we can grow considerable forage after July 1 with ample rainfall. So the question becomes, what is the probability that we are going to receive substantial rainfall in Miles City, MT in July and August? The answer to that can be obtained by looking at long-term weather records and calculating probabilities for obtaining varying amounts of precipitation over a 30 day period. This information is available on the internet and it shows that the probability of receiving a total of 2” of precipitation in July is about 20% and in August it is about 17%. Therefore, it is concluded that ranchers can make proactive drought decisions in early July with some certainty because most of their annual forage production will be completed by then.