April and October are particularly delightful if you want to avoid potential heavy rains in early spring or the hotter inland temperatures of summer and early autumn.
Summer (June-August) is the hottest time of year, especially inland, when the thermometer regularly hits the upper 30s (°C) and humidity is higher.
Winters (December-February) are colder and wetter, averaging 12°C (54°F) along the coast and 7°C (45°F) in Jerusalem, with occasional rain that can bring flooding to the Dead Sea and rivers/wadis in the south and cause some road closures.
When to visit for specific experiences:
Hiking: Spring and autumn, particularly March–May and September–November. Wildflowers bloom throughout March and April, making hiking especially beautiful.
Religious trips: Plan to coincide with Jewish (Rosh Hashanah, Yom Kippur, Sukkot, Hanukkah, Purim and Passover), Muslim (Ramadan and Eid al-Adha) or Christian (Christmas and Easter) holidays, but remember that most businesses are closed on these days. The Jerusalem International Book Fair is held in mid-June, and the annual Feast of Tabernacles is usually in October.
Beaches: June–September, when you’ll find the warmest sea temperatures and the liveliest nightlife. Note, however, that most Israelis and many foreign tourists head for the coast during July and August, so avoid if crowds bother you.
Bird-watching: March–April and October are especially good times to spot migrant species, both at coastal sites around Eilat and in the hills at sites such as the Gamla Nature Reserve.
Wildflowers: Late February to April. Spring rains bring forth vibrant carpets of wildflowers transforming open areas throughout the country. The northern Galilee and Negev Desert are particularly renowned for their displays.