Thassos is most northern island in the Aegean Sea and lies about 8km off the Macedonia mainland in the Gulf of Kavala. It has an area of about 390 sq km and is roughly circular at 22km wide and 26 km long and with a coastline of about 75 km.
Thassos is a mountainous island with the highest peaks at Ipsarion (1,127m) and Profitis Ilias (1,108 m). Much of the northern coast in inaccessible, with steep rock cliffs, while the south of Thassos is relatively flat.
The northern half has rich vegetation, with thick forests, olive groves and vineyards that are fed by many underground springs. The south is mostly unproductive agriculturally, although as much as 90% of the island is covered by pine forest, oak trees, and planes.
Thassos is also rich in minerals with lead and silver in the Limenaria area, copper around Astris, iron at Kalirachi and snow white marble, for which Thassos island is famous, found around Limenas.
‡ On Fridays there is a free tour of Thassos marble quarry at 10am, near Thassos Town on the Panagia road.
‡ In Panagia village there are daily tours of a traditional olive oil factory.
‡ The recently enlarged archaeological museum in Thassos Town is now open 7 days a week.
Thassos is the most northerly of the Greek holiday islands so its climate is cooler than most other Greek Islands especially at night. On the other hand Thassos is more sheltered from the prevailing northerly winds so it can feel quite humid.
The season starts in May when Thassos has lots of sunshine with only occasional rain. Showers can be heavy but are generally brief. Summer temperatures average 27°C in July and August then drop off to 25° in September. Unlike other Greek islands Thassos is not swept by cooling afternoon breezes. Sea temperatures hover around 20°C.
Winter in Thassos is milder than on most Greek islands. Average temperatures drop to 8-9°C and afternoons are often swept by rain. November can still have warm days and by April the temperatures are rising fast and the island is covered in wild flowers.
| JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | Averages |
| 11 | 11 | 15 | 17 | 21 | 26 | 28 | 28 | 24 | 21 | 16 | 12 | Day °C |
| 5 | 5 | 7 | 9 | 13 | 16 | 18 | 19 | 16 | 13 | 9 | 6 | Night °C |
| 5 | 5 | 6 | 8 | 9 | 11 | 13 | 12 | 9 | 7 | 5 | 4 | Sun (hrs) |
| 2 | 3 | 4 | 6 | 8 | 9 | 9 | 8 | 6 | 4 | 2 | 2 | UV Index |
| 140 | 129 | 91 | 68 | 43 | 18 | 10 | 16 | 48 | 125 | 172 | 184 | Rain (mm) |
| 12 | 11 | 10 | 8 | 6 | 3 | 1 | 1 | 2 | 8 | 11 | 13 | Rainy days |
