Last year's U.S. sales of plug-in electric cars were the highest on record, but now the traditional winter sales slump has set in with a bang.

Electric car sales usually dip during the coldest months, and last January was the lowest sales month of the year--but this January's results apparently even failed to match those of the same month a year ago.

The Nissan Leaf saw 1,070 sales last month, slightly down on last year's 1,252--but considerably higher than the 650 in January 2013.

DON'T MISS: FINAL UPDATE: Plug-In Electric Car Sales Continue Rise In 2014, To 118,500

Still, given that the Leaf's best month (August 2014) saw 3,126 sales, Leaf winter numbers are obviously down.

“We saw a significant increase in demand in December from customers looking to take advantage of Federal and state incentives at the end of the tax year," noted Brendan Jones, Nissan's director of electric vehicle sales and infrastructure.

That, he suggested, pulled some January sales ahead into December 2014--which logged a healthy total of 3,102.

2015 Chevrolet Volt

2015 Chevrolet Volt

The Chevy Volt, meanwhile, saw January deliveries of a mere 542, against 918 in 2014 and 1,140 in 2013. Again, that looks like some seasonal slump.

Low sales are less surprising there, since first-generation Volt sales are in a several-month wind-down before the arrival of the all-new 2016 Volt that was launched last month at the Detroit Auto Show.

And as always, Tesla Motors refuses to report monthly sales, so we have little idea how many have been sold.

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It may have been a good month for the company, though, as its production lines are apparently dedicated to cranking out the high-performance P85D all-wheel-drive model.

That's the hot car to have right now, given the blistering speed of its "Insane" mode, which accelerates from 0 to 60 mph in around 3 seconds.

Tesla Model S P85D 'Insane' mode acceleration [frame capture from DragTimes video]

Tesla Model S P85D 'Insane' mode acceleration [frame capture from DragTimes video]

The BMW i3 delivered 670 units, reverting to three-digit sales and its lowest total since last July.

Still, if BMW can resume selling at four-digit rates later in the year, the i3 will be a force to be reckoned with in the plug-in car market for the full year.

Plug-in hybrids

The Toyota Prius Plug-In Hybrid continued a several-month trend of losing steam, logging just 401 sales--its lowest total since September.

But Ford's pair of plug-in hybrid Energi models were down too.

MORE: 2016 Chevrolet Volt Video

Just 395 C-Max and 426 Fusion deliveries were logged last month, only one-half to one-third their numbers last summer and lower than their January 2014 totals.

And the plug-in hybrid Honda Accord, which has always sold in minimal numbers, came in at 28 units--similar to its volume a year ago at this time.

Low-volume vehicles

Among the dozen or so low-volume and compliance cars, those that mostly sell 200 a month or less, sales were also down from last year's levels.

Something of an exception were the pair of German newcomers not on sale this time last year: 240 Mercedes-Benz B-Class Electric Drives and 181 Volkswagen e-Golfs were delivered.

2015 Volkswagen e-Golf

2015 Volkswagen e-Golf

Both numbers were down on the December totals, but higher than November's, and sales of both battery-electric vehicles are still hitting their strides.

Cadillac sold 92 ELR range-extended electric coupes, and another 85 BMW i8 plug-in hybrid sport coupes found buyers as well.

2015 Nissan Leaf

2015 Nissan Leaf

The tiny Mitsubishi i-MiEV had the lowest sales total of the month, a mere 3 vehicles.

And even the Smart ForTwo Electric Drive sold just 147 cars, up on the previous January but only half the December pace.

Reporting troubles at Porsche meant we don't yet have figures for the Cayenne S E-Hybrid and Panamera S E-Hybrid plug-in hybrids yet. We'll add them when we receive them.

We don't know how many Kia Soul EVs were delivered because Kia refuses to release that data to the press.

Compliance cars

Of the compliance cars, just 7 Toyota RAV4 EVs were sold, as that car nears the end of its sales run, and Honda sold no Fit EVs at all.

The Chevrolet Spark EV came in at 86 cars for January, just slightly under last year's average monthly deliveries.

2014 Chevrolet Spark EV - Driven, July 2014 (NWAPA Drive Revolution)

2014 Chevrolet Spark EV - Driven, July 2014 (NWAPA Drive Revolution)

Ford Focus Electric sales were 85, down on the previous January's 100, and Fiat Chrysler Automobiles refuses to release Fiat 500e sales.

It's worth keeping in mind that January 2014 sales were about 6,000 vehicles with plugs.

So what happened?

And contrary to early expectations, it appears last month didn't quite hit that mark.

Which inevitably leads to the question: Could sustained low gasoline prices now be having an effect on sales of plug-in cars?

Data for the four-year period from December 2010 through November 2014 suggests no relationship between gasoline prices and sales of plug-in electric cars.

It will take a few more months before we can analyze whether the pace of electric-car sales is not growing over the early months of 2014, as would have been expected.

Perhaps it was just the snowy weather, perhaps there were other causes.

Watch for next month's data for more information.


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