Does a car battery really lose power faster in summer or is that just a myth?

[simregistration]

I've been hearing this from mechanics for years but never really knew if there's actual truth behind it. My 2018 Nissan Sunny has been acting weird lately, nothing major but just small things like the central locking seems slower and the radio station presets disappeared twice this month which never happened before. A friend of mine who knows a bit about cars said the battery is probably struggling because of the heat and that summer temperatures absolutely destroy batteries here in Sharjah. I wanted to understand the actual science behind this so I started searching online and landed on www.carbatteryreplacementsharjah.ae which had some useful information about how extreme temperatures affect battery chemistry and why the lifespan drops significantly in this region. But I'm still confused about one thing. If heat is the problem, then why do batteries sometimes fail on a cool morning instead of during a hot afternoon? That seems backwards to me. Also, is there anything I can do to protect my battery during the summer months besides parking in the shade which is not always possible? I've seen people putting those thermal wraps around their batteries but I have no idea if those actually help or if they just trap heat and make things worse. I don't want to wait until my car completely refuses to start before I take action, but I also don't want to replace a battery that still has life left in it just because of some general rule of thumb. Is there a way to know for sure if the heat has already damaged my battery or if it's still fine for another few months? I'd really appreciate it if someone who actually understands this stuff could explain it in simple terms without all the technical jargon. Thanks.