As for Muslim areas such as East Jerusalem, Gaza strip and the West Bank towns, they remain open on Saturday but are generally closed all day Friday. On Shabbat, most Israeli shops, offices and places of entertainment close down. Shabbat starts at sunset on Friday and ends at sunset on Saturday. The climate is clear anytime of the year. In winter, Jericho is a favourite resort and even the Jerusalem sun can be warm during the day.
Winter can be cold, rainy with the possibility of snow in some areas.
In summer, the only problem is how to cool off. The visitor can be better off heading for the higher and drier places inland. Spring is definitely the best time to visit, the weather is temperate enough making it enjoyable to travel around.