Dress in Israel is casual. It is likely to be quite warm, although evenings and early mornings may be a bit cooler. In the evenings, a light jacket or cardigan is a good idea when visiting higher elevations such as Jerusalem. The rule of thumb is to dress in layers. At all times of the year, bring head coverings for protection against the sun (sunglasses and sunblock are essential) and wear comfortable walking shoes. Expensive jewelry, electronics and other valuables should be kept to a minimum.
General Guidelines: Casual dress. Shorts, jeans, t-shirts, etc. are appropriate during the day. Bring a light sweater or jacket for chillier evenings, mornings and any places where the air conditioning may be on full blast. Wear comfortable walking shoes and be sure to bring a hat and sunglasses!
Special Events and Shabbat: Shabbat dinner and any special events with dignitaries and high-level officials usually require business or business casual attire. For men, a pair of slacks and a collared shirt is appropriate. Jackets are optional. For women, a nice skirt, dress or dressier pants are appropriate.
Western Wall & Other Religious Sites: It is important to dress modestly when visiting observant areas or religious sites. Avoid tank tops. For women, this usually means a long skirt or shorts at least mid-calf in length and covering shoulders.