All foreigners need a visa to enter Jordan. You can get one at the border or airport when you arrive, or from consulates in your country.
Visas are valid for two weeks from entry, but can be easily extended up to three months.
Keep your passport on you whenever you're near the Israeli border, as there are lots of military checkpoints. No particular risks, but you should consider vaccinations for hepatitis, typhoid, polio and tetanus and diphtheria. When to Go The best time to visit Jordan is in spring or autumn, when you can dodge the baking sun of summer and the freezing winds of winter. Although winter can be bitterly cold in most of the country, the Red Sea area and Aqaba are still very pleasant. If you're planning to travel through the rest of the Middle East, try heading north into Turkey around spring, or south into Egypt by autumn.