Earnings season is over, and the only thing notable about it was how boring it turned out to be.

Except for some scary corporate outlooks.

In fact, it’s what companies are saying about the current quarter — where weather excuses abound — that should make the next earnings season harder to pin down and even pockmarked with negative surprises.

And most importantly, it could threaten a still highly valued broader stock market.

Q4 Earnings: Ho-Hum.

At least a tumultuous first quarter will make things more interesting … because Q4 earnings were as boring as they were weak.

Earnings growth came in a little bit better than expected in the final quarter of last year, and revenue did too. The beat rate — or percentage of companies exceeded analysts’ average estimates — landed right about where it always does too.

For Q4 2013, companies in the S&P 500 posted a growth rate of 8.5% year-over-year, according to data from FactSet. That’s significantly better than what analysts expected at the end of last year, when they predicted growth rate stood at 6.3%.

Revenue growth was astonishingly weak once again, but that doesn’t surprise anyone. S&P 500 revenue increased 0.8% in the final three months of last year, vs. a forecast of 0.3%. Better-than-expected profit growth on stagnant revenue has become the defining feature of corporate earnings for several years now.

The beat rate didn’t make any news either, as 65% of S&P 500 companies earnings surpasses analyst expectations, according to data from Thomson Reuters. That figure split the difference between the long-term average of 63% and the average over the past four quarters of 66%.

Nothing to see here, folks.

Another Crummy Earnings Season on Tap

What is worrisome is what companies have been saying about business in the current quarter.

Mostly, it’s not good, and they’re all getting ready to blame the snow and cold.

FactSet found that the term “weather” was mentioned at least once in 195 post-earnings conference calls with analysts and investors. That’s an increase of 81% over the year-ago period. Urban Outfitters (URBN), McDonald’s (MCD) and General Motors (GM) are three just three disparate companies already blaming the weather for sales and earnings shortfalls.

As part of that, there have already been 96 negative profit warnings out of S&P 500 companies, vs. 15 instances of raised outlooks. That makes the ratio of positive to negative pre-announcements 6.4 — much higher than the 4.1 seen a year ago, as well as the long-term aggregate of 2.5.

All those profit warnings have analysts marking down their estimates. Although we still have a couple of weeks left in the first quarter, it’s already looking like a dud by Wall Street’s reckoning.

S&P 500 profits are forecast to grow just 0.3% in the first quarter, down from the 4.4% growth projected at the end of 2013, hurt by rising costs. Indeed, in a twist, revenue growth is pegged to be stronger than earnings. Analysts see the S&P 500’s top line increasing by 2.6% in the first quarter (down from a 3.2% forecast on Dec. 31.)

So even if the beat rate comes in as it always does, exceeding estimates by the same 3% average it did in the fourth quarter, Q1 is shaping up to be crummy even by the low standards we’ve had to adopt in the post-crisis period.

There’s no doubt that unusual winter weather affected corporate results, but that doesn’t tell the whole story — a whole story that hasn’t changed since the financial crisis.

Record-high earnings are being driven by costs cuts, not revenue growth. It all comes down to margins. Heck, the current period is expected to produce the best top-line growth in a couple of years, and yet earnings are in danger of flatlining because winter dumped a mountain of unexpected expenses (and convenient excuses) on corporate results.

But beneath that seasonal anomaly remains the fact that half of the sectors in the S&P 500 now have profit margins running below forecast — and stocks are getting more expensive.

The damage done by the polar vortex is going to get big play. Anything that can take the heat for shrinking margins and crappy earnings is almost a gift to CFOs.

The tale of these two earnings seasons remains the same, however: Earnings and revenue growth are stubbornly hard to come by and margin expansion can only work so much for so long.

That’s the biggest threat to an increasingly pricey bull market.

As of this writing, Dan Burrows did not hold a position in any of the aforementioned securities.