@alexkmg,

I think you've got it backwards. Winter is when the sun shines. We had solar in our first apartment and had hot water all winter. Come the rainy season with cloud cover we had to install an electric heater.

@Alexkmg is right. The sun always shines of course - winter and summer. The odd summer cloud isn't enough to stop the water getting heated nicely, but winter nights cool the stored hot water fast. We have a solar/electric system so the electric heater kicks in whenever the solar-heated water temperature goes below a set minimum. Never need electiricty it in the summer. Nearly always on in the winter.

When we had solar only we went for as much as five days in the summer with no hot water. Never went without in the winter. Maybe we had a unit with better insulation on the tank.

Insulation could indeed be the reason. I guess warm water in the winter is more useful anyhow. A cold shower is sometimes just what's needed in the hot summer.

We've lived here for 12 years. I'd think the most important thing is the clothing and shoe sizes for the adults. I'm a lady 5'8", size 8 clothes, and I rarely find anything big enough or long enough for me here. I wear size 8.5 or 9 shoes, so I bring stuff from the U.S. My husband wears M or L in U.S., and we have to bring clothes from U.S. for him as well. You will need some jackets or coats that will cut the wind. My family has had problems with sickness, I think, from fluctuating temps inside and forgetting to layer appropriately. We keep one bedroom warm with heaters during the day. It's so dry that you can hang your wet laundry inside, and it drys fairly fast and helps the humidity, or you can purchase humidifiers. Some people have problems with nosebleeds because of the dryness. I can't stand ice in my drinks anymore, but my husband still does! We are from Arkansas. Hope this helps....

@AlPage48

That's quite interesting. It's very good to know that it can work fine during winter. Most of the stories I have point to solar water heating not working out well in winter, but maybe that's because most of the units were old and not well insulated.