The Beast from the East, which shut down much of the country in 2018, has been blamed for Scotland missing a climate target.
Unseasonably cold temperatures and heavy snowfall brought transport to a halt and closed schools in late February and early March two years ago.
Scotland’s Environment Secretary has told the Scottish Parliament an increase in energy usage during the cold snap has contributed to a 1.5% rise in greenhouse gas emissions between 2017 and 2018.
It meant the Scottish Government missed its own climate target to reduce emissions by 54% compared to the 1990 baseline, which was put in place through legislation last year.
In statistics published on Tuesday, emissions were found to have reduced by 50%.
Speaking at Holyrood on Tuesday, Ms Cunningham told MSPs: “This outcome is certainly disappointing but we should not lose sight of two things.”
She said the targets were set to provide “an extremely stretching pathway” to net-zero, which “will inevitably face challenges”.
Ms Cunningham added: “Today’s statistics do highlight one such setback, with changes to the national energy mix and freezing temperatures from the Beast from the East in the early months of 2018 contributing to a rise in emissions from energy supply and heating used for buildings.”
The statistics show a rise of 800,000 tonnes of carbon dioxide equivalent in the energy supply, a jump of 13.4% between 2017 and 2018.
Ms Cunningham said: “We remain absolutely committed to ending Scotland’s emissions contribution by 2045, with a 75% reduction being achieved by 2030.”
The Environment Secretary said the figures do not reflect more recent efforts to tackle the climate emergency.
“The actions not yet being picked up include most aspects of our 2018 climate change plan,” she said.
“It also misses all of the measures announced following the First Minister’s declaration of a global climate emergency in 2019.”
The deposit return scheme, an increase in funding for peatland restoration and a funding boost for Energy Efficient Scotland to more than £150 million are among the actions taken since 2018, according to the Environment Secretary.
The Climate Change (Emissions Reduction Targets) (Scotland) Act 2019 set a target of achieving net-zero emissions by 2045, with the Scottish Government to publish annual updates on progress.
It set a target on 2018, which had passed by the time MSPs voted on the Bill in September 2019.
The target for 2020 is currently set at 56%.
Conservative environment spokeswoman Annie Wells questioned Ms Cunningham’s explanation that cold weather was to blame, adding there needs to be a “clear road map” to net-zero.
Claudia Beamish, the Labour environment spokeswoman, described missing the target as “disappointing”, saying there should be “robust and urgent action now” to meet the 2030 target of 75%.
Liam McArthur, the Lib Dem energy spokesman, described the missed target as “damaging”.
Mark Ruskell, the Scottish Greens MSP, said the Scottish Government “failed to have any positive impact whatsoever on transport emissions”.
These dropped by 1.1% between 2017 and 2018.