Cyclone season is normally between November and April but cyclones can occur throughout the year. Severe weather may result in flooding, landslides, and disruption to essential services and infrastructure. See Natural Disasters
A severe weather warning is in effect for Tonga due to Tropical Cyclone Gita. Tropical Cyclone Gita is expected to make landfall on the afternoon of Monday 12th of February and strong winds and heavy rain are expected. It may cause flash flooding and landslides and could severely disrupt essential services. Monitor local media, including local radio broadcasts, for updates and follow the instructions of local authorities. We strongly advise that you do not venture outdoors and remain well away from the sea, due to the possibility of storm surge. There is no permanent UK diplomatic presence in Tonga. Therefore for emergency consular assistance, please contact the New Zealand High Commission in Nuku’alofa on +676 23122 or afterhours +676 8817022. For routine consular assistance, please contact the British High Commission in Fiji on +679 322 9100
There is 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.
Although there’s no recent history of terrorism in Tonga, attacks can’t be ruled out. 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.
UK health authorities have classified Tonga as having a risk of Zika virus transmission. For information and advice about the risks associated with Zika virus, visit the National Travel Health Network and Centre website.
If you’re abroad and you need emergency help from the UK government, contact the nearest British embassy, consulate or high commission.
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.
Source Article from https://www.gov.uk/foreign-travel-advice/tonga