Volatility in the currency markets, bond markets, and stock markets likely has a lot of people on Wall Street feeling a bit worn out. Taking a summer vacation in the Hamptons might just be their best idea.

The coming months promise to be anything but quiet and predictable. Here are a couple of items that may yield profound implications for stock, bond and currency investors before summer ends...

The Threat of an Official Recession Is Looming

The next few months are critical for the U.S. economy. The official definition of recession calls for two successive quarters of negative GDP. First quarter GDP came in barely positive, initially estimated at 0.2%, but it will be revised twice before July. Some experts expect it will wind up in negative territory.

The U.S. trade deficit recently came in much larger than expected. The higher deficit will, setting other factors aside, translate to lower GDP. Investors will get a look at 2nd quarter GDP in late July and pessimism among forecasters is growing.

So far U.S. equity investors are hoping for the best, or at least hoping the Fed will reverse course on tightening. Stocks are shrugging off bad news and powering higher with price-to-earnings valuations climbing into the nosebleed section.

It is hard to imagine valuations at these levels holding if investors and high frequency trading algorithms must grapple with an official recession. Of course, should the Fed announce some new form of stimulus in response to bad news then all bets are off.

The End Is Nigh for Greece

The Greek government is running out of tricks to avoid a default. Last week, officials there paid €750 million Greece owed to the IMF by borrowing €650 from the IMF; a last resort gimmick they won't be able to repeat.

Absent finding an agreement with lenders to modify loans and dramatically reduce what is owed, the Greeks will be in outright default as early as next month. This summer should tell the tale on Greece's future within the European Union.

Should Greece default and exit the EU, it will be the first event of its kind, and it has the potential to open a Pandora's Box. There will be bank failures within Greece and pain for anyone holding Greek debt. It could pave the way for bankruptcy and an exit in a number of other nations where finances are also in shambles. And no one can confidently predict the outcome in derivatives markets where banks and hedge funds have been making highly leveraged bets.

Should the Greeks manage to reach an accord with lenders, markets will have to contend with a different set of challenges. You can bet other overly indebted nations including Ireland, Spain, Portugal, and Italy will aggressively pursue similar deals. The pain for bond holders isn't likely to end with Greece.

The EU has a flood of bad debt swirling around its knees, but officials there continue to pretend they stand on solid ground. Regardless of whether Greece defaults outright or manages to cut a deal, it looks like the pretending will have to stop - and soon.