The tropical cyclone season normally runs from November to April. You should monitor the progress of approaching storms on the website of the Tonga Meteorological Service and follow the advice of the local authorities. See Natural Disasters
There’s no British diplomatic representation in Tonga. The British High Commission in Suva can provide routine consular assistance. In an emergency you can also contact the New Zealand High Commission in Nuku’alofa.
There is a low threat from terrorism. See Terrorism
Most visits to Tonga are trouble free. The crime rate is relatively low. However, petty crime and theft do take place. You should remain vigilant, especially at night. See Crime.
Take out comprehensive travel and medical insurance before you travel. Medical evacuation from Tonga is required for most non-basic medical problems. You should make sure that your policy covers you for medical evacuation by air ambulance.