It's been a while (well decades) since I used road tyres, but at least mountain bike tyres are famously recommending way too high pressure. I run about 1.3 bar in mine, while the recommended pressure on the tyres are 2.0 if I'm not mistaken.

And 2.0 is impossible to ride with. Apparently they do this to avoid lawsuits if the tyre punctures so they can argue you were running them out of spec.

Maybe they store their bike somewhere unheated and the drop is temp has meant the pressure got too low?

I suspect OP doesn’t cycle every week, but is planning to very soon. That’s when this kind of maintenance check is particularly useful.

If you do cycle every week, you’ll notice pretty quickly if the tires are in need of some more pressure. In that case, there’s no need to plan ahead. You just go when you need to go. There’s no need to think about the tires every time.

Tires are made to operate with a certain amount of pressure in them, that's written on the outer tire. Too little and you risk more leaks, not to mention it just takes more effort cycle.

If you want more stability and grip, you want bigger tires, like an ATB or mountain bike.

It's great that you're at least cycling now and then! For me it's my primary mode of transportation... Which is possible because the Netherlands has great cycling infrastructure.

I imagine everyone using cars for everything in other countless must be a lonely thing... Not to mention all the environmental impact 🙁

If your tire does not break through to a solid surface, you will not get traction on snow regardless, unless you are using either absurdly large balloon tires, or a tracked vehicle. More pressure ensures that any knobs or studs or treads have the best chance possible of finding traction.

Interestingly, lower pressure and higher contact patch does not actually reduce efficiency on dry asphalt either. This is because elastic tire deformation is highly elastic, but the increase in rolling friction is small. In contrast, overly stiff tires convey more vibration into the frame, which is lost as heat, instead of being conserved elastically. Even on perfectly smooth indoor tracks, just they hysteresis losses from pedaling on an overly firm tire add up significantly.

I got studded tires but I haven't put them on yet because it has been a weird year with zero snow so far.