Opinions on this 2021-22 NBA season are being firmly formed as we enter February.

Last month saw the All-Star starters announced, while the MVP race hotted up – or cooled down, with several early contenders struggling with form and fitness.

But who really lit up the league in January? And whose bright end to 2021 did not carry over into the new year?

Stats Perform's NBA Heat Check looks at the best and worst performers of the month...

RUNNING HOT...

RJ Barrett

Now in his third year with the New York Knicks, Barrett's has been a season of peaks and troughs. In the month of November, he averaged 12.8 points per game; in January, that mark was a mightily impressive 21.8.

Such inconsistency leaves the guard just below last year's average of 17.6 at 17.3, but he is now a man in form, scoring double-figures in 17 straight games – including all 15 in January.

Barrett's 31 points against the San Antonio Spurs on January 10 were followed by 32 against the Dallas Mavericks on January 12 in consecutive wins, before the Knicks traded for Cam Reddish, his old Duke team-mate, the next day. As stretches go, this was a good one.

Reddish is yet to find his feet in New York but at least finds a familiar face full of confidence in the locker room.

Kyle Kuzma

January finished with the Washington Wizards on a five-game losing streak that was extended to six on Tuesday, but it was a month of progress for Kuzma.

Comparing output for the past month to the rest of the season, Kuzma ranked second in the league for an increase in both scoring (up from 13.4 to 22.5) and rebounding (up from 8.0 to 11.1).

While this form is clearly not doing enough to get the Wizards' year back on track, it is at least providing the Los Angeles Lakers with a reminder of what they gave up in a trade for Russell Westbrook.

Kuzma was one of three players, along with a first-round pick, sent to Washington in exchange for Westbrook, who has again flattered to deceive and appears to be back on the market with the Lakers toiling at 24-27.

Anfernee Simons

One place behind the Lakers in the West, the Portland Trail Blazers are similarly out of sorts, with Damian Lillard falling below his usual standards and the rest of the team struggling to pick up the slack.

The Blazers have still had some breakout stars, however, with Simons the most obvious of those in year four after a dazzling January.

Already averaging double-figures at 11.9 heading into 2022 – something he had failed to do in his previous three campaigns – Simons was the most improved scorer last month, scoring 23.1 points across 15 games. He made 4.5 three-pointers per game over that period, also a league-leading improvement on his prior 2.0.

Third-year forward Nassir Little (13.1 points and 2.1 threes in January) ranked seventh and fifth by those metrics, only to sustain a season-ending labrum tear – a setback that just about summed up Portland's season.

GOING COLD...

Stephen Curry

Curry's 26.0 points per game this year are up on two of his three title-winning campaigns with the Golden State Warriors but significantly down on last year's 32.0 – enough to win the scoring title – and falling rapidly from his early-season standards.

The two-time MVP made a hot start with 28.7 points in October and was still operating at 27.7 come the end of 2021. In January, however, he scored only 22.3 points – the biggest drop in the NBA.

Curry also led an unwanted chart in seeing his 5.4 made threes per game decrease massively to 3.5, a career 42.9 per cent three-point shooter and 47.3 per cent field-goal shooter slumping to 32.9 per cent and 38.5 per cent.

Such is the depth of talent on the Warriors' roster – in Kevon Looney and Jonathan Kuminga, they had two of January's three most-improved rebounders – they have been able to ride out Curry's rough patch. However, Jordan Poole had also been struggling to maintain his high standards (fifth for scoring decrease in January), though a 31-point effort in Tuesday's win over the Spurs hinted at a return to form.