The September jobs numbers are easily the worst of 2015 so far. They offer an unpleasant combination of a bad overall headline, bad details and bad timing, amid a volatile and unsettling time in global markets.

The weak numbers offer some vindication for those Federal Reserve officials who preferred to hold off on interest rate increases last month to ensure the economy was on sound footing before tightening the money supply. They also give reason to worry that those wild market swings in August were less random fluctuations and more an indication that something deeper is wrong with the global economy — not so much that the stock market drop in August caused weak September jobs numbers, but that there is an underlying economic fragility causing both.

The question now is whether it means anything — whether the United States economic expansion, which seemed set to roar into 2015, is slowing in some meaningful way. We don’t know that yet, and it would be a mistake to leap to that conclusion. But that possibility became quite a bit more plausible after the September numbers popped onto economists’ computer screens.

As always, it is a useful exercise on jobs report Fridays to take a deep breath and remember that this is but one set of indicators, with a large margin of statistical error, that will be revised repeatedly. But the fact that the latest jobs numbers are consistent with another report, from the Institute of Supply Management, earlier this week that suggested United States manufacturing slowed to a standstill in September doesn’t do anything to help an economy-watcher maintain that zen perspective.