The months of August and September are notorious for dramatic declines in the stock market, and Jim Cramer warned investors to be mentally and financially ready when it happens.

Stocks fell last week after a combination of weak retail earnings and bank stock performance spooked some investors.

“In the dog days of summer, we can get hit with lightning speed sell-offs,” the “Mad Money” host said.

Rather than join the masses of scared investors in the next downturn, Cramer recommended to view it as a buying opportunity. That means having some cash available, and stock ideas on hand that could be put to work in a “cool and methodical” way.

Cramer wasn’t spooked by the sell-off last week. His charitable trust took action and purchased stocks like Nvidia and Activision Blizzard on weakness.

“Despite the fact that everyone was freaking out, the positive backdrop for stocks didn’t change. We have low inflation, low interest rates, good earnings and a weak dollar,” Cramer said.

Low inflation means that earnings for companies could be worth more in the future. Cramer often considers low inflation to be a gift, as high inflation could erode the long-term value case for equities.

Additionally, low interest rates can act as a positive catalyst to spur business in the U.S., and prompt investors to buy stocks with strong dividends.

Regardless of the positive implications of interest rates or inflation, Cramer still had reservations.

The first on his list was that Congress is not in session currently. In his perspective, both sides of the aisle are at odds with President Trump. Thus, the market could move higher while Congress is not in session, and then be impacted negatively when it reconvenes in September.

Other worries on Cramer’s list were technology stocks, the recent bounce in transportation stocks and interest rates.

“Interest rates went higher today, and that should continue, but for the most part it hasn’t and we have been stalled,” Cramer said.

Ultimately, Cramer recommended investors to start selling the worst stocks in their portfolio that have managed to go up as a part of the broad rally and have some cash on hand for the next downturn.

Watch the full segment here:

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