The bleak weather, coupled with tight Covid rules, can play a large role in affecting one's mood.
But there is a simple way to help stay positive and that is through gentle forms of exercise.
That is the message from personal trainers who have adapted to lockdown by holding sessions online.
Jimmy Whittall, aged 34, from Kidderminster, says exercise has many health benefits.
His routines can be done in the comfort of people's homes although he encourages people to exercise outside.
Mr Whittall said: "To stay fit, the best thing people can do is getting your steps in. And that is for all abilities.
"While people can still go outside, most phones carry step counters now.
"It is looking at getting above 8,000 steps a day. Anybody can do that, it is an easy hour of walking to do."
To advance on walking, he encourages people to run and do resistance training.
This can be done using weights at home or other heavy objects. He also recommends using resistant bands and a punch bag.
"Thirty to forty minutes of exercise a day will boost your mental health," he said.
Jimmy said exercising outside is particularly beneficial as it maximises people's exposure to "sunlight and Vitamin D".
"Something that people with depression tend to do is stay indoors and stay inside, and shut themselves off from the world," he said.
"When you do go outside, it is a big step for people to do.
"But it can really boost your mental health, although the sun is low this time of year. It is still good to go outside and get that fresh air inside of your lungs.
"I have never known anybody, even if you have done a really tough workout, to feel terrible after a workout.
"I'm talking about mentally with the endorphins."
Jimmy says exercise helped to improve his life as he was overweight and suffered with depression.
He has been a personal trainer for six years, although for the first three years, he worked around his former job as an assistant manager at Aldi.
He said: "It was what kick-started me because I was overweight, I was depressed, I was on anti-depressants and stuff.
"I basically turned my life around one day and thought I can't keep living on medication.
"I took up fitness as a way of battling that and I have never looked back since."
During lockdown, he has been holding one to one sessions with clients over Zoom.
To follow Jimmy's work, follow fitnessbyjimmy on Instagram and Facebook.