As goes January, so goes the year?

Or "As goes Guam, so goes Samoa".
[huh? -ed)
From MarketWatch:

The market is set for a 7% drop in January, not boding well for the rest of the year, if one believes the old adage.

According to research from Quantitative Analysis Service, the month of January tends to predict the direction the market will take for the year accurately 65% to 75% of the times.

"That's not an impeccable record," says Ken Tower, market strategist and senior vice president at the firm. "But, along with April, it definitely has a better track record at predicting the year than any other month in the year."...

...Voodoo 'Monthanomics'?

Some market strategists who rely on technical analysis use January's success at predicting market action, not because they believe in astrology, but simply because it's worked historically....MORE

The Guam line is a ref to the fact that Guam's caucuses have predicted the Presidential election since 1980 i.e. "As goes Guam so goes the nation" . Barack Obama had 62% of the vote, beating Hillary Clinton in a "Guamslide".
It is itself a play on Richard Nixon's quote "As goes Ohio, so goes the nation".
Someone else probably said "As goes Virginia, so goes the nation" back in 1789.
(Or Rhode Island? -ed.)