For small fences, as you said, they are ok! They don't make the best jumpers like warmbloods, but they are so nice to have some fun!! My horse is a lusitano (PREs and lusitanos are like brothers or cousins, very very similiar) and i've jumped him up to 1m10 at home and 1m in competition. They are super nice to ride, love to please and do everything for you, literally everything, they put their heart into everything you ask them!
Cold weather is not a problem as long as you provide him with shelter.