It’s the kind of rain that soaks you right through.
And it’s happening as a group prepares to undertake an hour’s intensive exercise on Southsea Common.
But the rain does not deter this motivated group and they get under way – bursting into running, sweating, doing push-ups and burpees and generally putting most people to shame.
For this is a relatively new phenomenon that has swept the country, which has seen people ditch their gym memberships in favour of paying someone to shout instructions at them outside, whatever the weather.
The Southsea branch of British Military Fitness meets six times a week outside the Queens Hotel in Southsea.
It’s run by park manager Tristam Murdoch, a former Royal Marines Commando, who is now working as a personal trainer.
Tristam takes the class along with four other instructors – all of whom have forces connections.
Tristam, 30, says: ‘It is a very effective form of exercise. You can burn up to 700 calories in just one session and you can cover up to 5km just doing the workout.
‘It is a great way to get fit.’
Tristam, who started working for British Military Fitness as an instructor five years ago, has seen a surge in new members since he took over as manager two years ago.
His numbers have grown from 90 to more than 150 since 2013, something he says is down to recommendations from existing members who have seen the health benefits first-hand.
Tristam says: ‘It is growing and growing and growing. And that’s all down to the fantastic people in the group. The members have sold it to other people.
‘It is all down to word of mouth – that’s the most powerful form of advertising.
‘They are experiencing it and then telling their friends.’
These classes lower stress levels for people who work in high-powered jobs or in offices because of the outside nature of the exercise. When you go to a gym you don’t get that.Tristam Murdoch, park manager and former Royal Marines Commando
But what is it that’s got these people talking?
Tristam says: ‘We exercise all year round. I know it’s raining today which is not great, but we’ve had a good turnout.
‘We’ll also be here if it’s snowing. We are here all the time, unlike other fitness companies.
‘The worst conditions I’ve been out in was when it’s been raining from all angles and the wind was blowing a gale.
‘But one of the sayings I have always adhered to is that it always looks worse through a window.
‘Once you are out there, you are fine. It’s sometimes just finding the motivation to get out and get amongst it when the elements are deteriorating.
‘Southsea Common can be a bit unforgiving in the winter months, but that’s fixed by getting people to buy the right kit.
‘These classes lower stress levels for people who work in high-powered jobs or in offices because of the outside nature of the exercise.
‘When you go to a gym you don’t get that. If you have a stressful job, or are having a stressful time with the kids, or have even been stuck in a traffic jam, it will help.’
The group meets and starts with a warm-up, before heading off across the Common.
They are split into three, with different-coloured bibs indicating different levels of fitness.
There’s continuous movement for an hour and the training methods vary from class to class, using different terrains, like the beach, the volleyball court and the Common.
Tristam says: ‘As we pay the council, we can travel anywhere and everywhere on Southsea Common.
‘When we exercise we don’t stay in one place, we move up to 5km and do different bodyweight exercise using the different kits we have like power bags, slam bags, dumbbells and weighted bars.
‘It is very good fun and very dynamic. You work every part of your body as opposed to one specific muscle group.
‘There’s also the social aspect of it all.
‘After a while exercise, for anybody, can become a bit of a chore, but with this that doesn’t happen as we are all together and it’s so varied.
‘We go out together for drinks and food, so as opposed to a gym which can be quite anti-social, this is more social.
‘You first join to get fit, but it’s also about the friendships that you build.
‘Any group would be a bit boring if it was not for the banter and the fun and the social element of it.’
British Military Fitness is the only recognised fitness company that uses the whole of Southsea Common.
The company was set up by Major Robin Cope in 1999 and now there are more than 500 instructors taking 400 classes a week at 140 venues. The first session is free and there are also classes held on Southampton Common.
Tristam, of Southsea, says you don’t have to be fit to join and the supportive nature of the team helps people settle in, although he does warn that you’ll ache after the first session.
He says: ‘It is for anyone and everyone. It is for all abilities and all ages - as long as you are 16 or above.
‘We have a whole range of different people who attend – different ages, sexes and abilities.
‘Recently we had someone join who wanted to get fit enough to join the Royal Marines and we also have had a woman five months’ pregnant, so it’s very diverse.
‘Sometimes people think British Military Fitness will be like a boot camp with people screaming and shouting at them, but it’s not like that at all.’
For more information go to britishmilitaryfitness.com
Sessions run six times a week. A monthly unlimited membership starts at £34 per month or 10 sessions can be bought for £110.
To see a video with this feature, go to portsmouth.co.uk/video