January has historically been a tough month for plug-in electric car sales, and last month doesn't look like it'll be an exception.

Added to the usual winter slowdown in electric-vehicle sales were the effects of Winter Storm Jonas, which effectively closed parts of the Eastern Seaboard for several days, car-shopping included.

After a 2015 with plug-in car sales slightly lower than those of the previous year, electric-car advocates will be watching the sales curves this year with great interest.

DON'T MISS: Plug-In Electric Car Sales For 2015 Fall Slightly From 2014

The first numbers to arrive today were deliveries for the Nissan Leaf, which totaled 755 last month--down from 1,070 in January the previous year.

Leaf sales in the U.S. last year plummeted from a record 30,200 during 2014 to just 17,269, likely reflecting knowledge of the 107-mile 2016 models now arriving at dealers.

Whether that update will boost Leaf sales back to their 2014 levels or beyond remains to be seen over the course of the year.

2016 Nissan Leaf SL, Hudson Valley, NY, Dec 2015

2016 Nissan Leaf SL, Hudson Valley, NY, Dec 2015

The 2016 Chevrolet Volt is now available at dealers in California and a few other states, with the full 50-state rollout of a slightly updated 2017 Volt to come between now and the end of spring.

Sales of the Volt last month came in at 996, up from an anemic 542 the previous January, but far from the Volt's best-ever sales month of more than 2,500. 

Green Car Reports named the 53-mile second-generation Volt our 2016 Best Car To Buy, and it has won several other awards on top of that.

ALSO SEE: Chevrolet Volt: Green Car Reports' Best Car To Buy 2016

Tesla Motors, as always, refuses to release its monthly sales or break down quarterly sales by country, region, or model.

So we can't report on its sales of the Model S electric sedan or the new Model X crossover utility vehicle with its unique but problematic "falcon doors."

Other high-volume plug-in cars are the BMW i3 and Volkswagen e-Golf battery-electric hatchbacks, the Smart ForTwo Electric Drive minicar, and Ford's pair of Energi plug-in hybrid models (whose sales will be released tomorrow).

BMW i3 and Volkswagen e-Golf electric cars using Combined Charging System (CCS) DC fast charging

BMW i3 and Volkswagen e-Golf electric cars using Combined Charging System (CCS) DC fast charging

It's possible that the Audi A3 e-Tron plug-in hybrid hatchback will become one of those higher-volume vehicles; it sold a whopping 327 units in just its second month on the market.

That follows December sales of 49 units in a single day, the very last sales day of the month. Put together, the two numbers may indicate a promising future for Audi's first-ever car with a plug.

Beyond those come a number of lower-volume all-electric vehicles and the two remaining California compliance cars for which data is released.

WATCH THIS: 2016 Toyota Prius Vs 2016 Chevrolet Volt: Video Test

Those include the low-range Mitsubishi i-MiEV minicar, the Mercedes-Benz B 250e, the Ford Focus Electric, and the Chevrolet Spark EV.

Among the low-volume plug-in hybrids are a growing host of models from Audi, BMW, Mercedes-Benz, Porsche, Volvo, and soon Audi.

Another 67 units of the Cadillac ELR range-extended electric luxury coupe were sold, bringing that model's total sales since December 2013 over the 2,400 mark.

2016 Audi A3 e-Tron Sportback, San Francisco Bay Area, Oct 2015

2016 Audi A3 e-Tron Sportback, San Francisco Bay Area, Oct 2015

As well as the two Tesla models, we will not receive sales figures for the Kia Soul EV or the Fiat 500e.

Their manufacturers refuse to break out those versions from the sales of their model lines as a whole.

We will update this post throughout the day and also tomorrow as more data becomes available.

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