The climate is influenced by monsoons and the sea. There is a distinction between dry and rainy seasons, but the temperature is more stable than other parts of Thailand. Rainy season lasts from May to November, approximately 6 to 7 months a year. Winter covers December to January, while the three months of February to April are hot and dry. Annual precipitation totals 1,013.52 millimeters with most rainfall in October, with 288.32 millimeters, while December has the least, with 12.72 millimeters.
The annual average temperature is 27.71 degrees Celsius with highs in May is 29.45 degrees Celsius, and the lowest average temperature in January is 25.65 degrees Celsius. The area is relative humid, with the annual average relative humidity is 75.97%. The highest average humidity in October is 82.4%, and the lowest average relative humidity in December is 69.1%. Visibility is normally very good.

      Hat Wanakon National Park has is home to plants at 0-5 meters above sea level and a total of 116 plant species were discovered. The study of plant species with a diameter at the chest height of more than 4.5 centimeters in the forests of Hat Wanakon National Park, Mueang District and Thap Sakae District in Prachuap Khiri Khan Province, found that the plants with the highest relative density were Bushwillows <i> (Combretum quadranguare) </i>, Siamese Neem <i> (Axadirachta indica), Suregada multiflora </i> (A. Juss.) Baill, Wattle <i> (Acacia auiculiformisr) </i>, and <i>Croton oblongifolius </i> Roxb respectively.
The plants with the highest relative frequency were Siamese Neem <i> (Axadirachta indica), Suregada multiflora </i> (A. Juss.) Baill, Bushwillows <i> (Combretum quadranguare) </i>, Wattle <i> (Acacia auiculiformisr) </i>, and <i>Croton oblongifolius </i> Roxb respectively. The plants with the highest relative predominance were Wattle, followed by Siamese Neem tree, Bushwillows <i> (Combretum quadranguare), Suregada multiflora </i> (A. Juss.) Baill, and <i>Croton oblongifolius </i> Roxb respectively.

Siamese Neem <i> (Axadirachta indica) </i> are scattered throughout the area and of high ecological significance because it grows in clusters and rows, so provides stability to the area. Other plants that benefit are Wattle and Australian Pine. Index of the plant species was considered and found that the Siamese neem tree had the highest ecological significance index. followed by Bushwillows, Wattle, <i>Suregada multiflora </i> (A. Juss.) Baill, and <i>Croton oblongifolius </i> Roxb respectively.

        There are 71 species of larger plants such as Siamese neem (Axadirachta indica), Bushwillows (Combretum quadranguare), Wattle (Acacia auiculiformisr), Suregada multiflora (A. Juss.) Baill, Croton oblongifolius Roxb, etc. Plants with a diameter at the height only up to the chest is 4.5 centimeters or more (big wood) such as Casearia grewiifolia Vent., Ramontchi (Flacourtia indica.), White – Meranti (Shorea roxburghii), Lagerstroemia speciosa, etc.
The structure of the forest in Hat Wanakon National Park found that most of the plants are small plants, with a height in the range of 4.0 – 6.5 meters. introduced Grewia microcos, Millettia leucantha, Vitex pinnata, Dialium cochinchinensis, Plants with a height of 9.0 meters or more are plants that have been introduced by humans in forest plantations, such as Siamese Neem, False Mahogany (Swietenia macrophylla), and Australian Pine.

        The forest area in Hat Wanakon National Park was originally an area with planted forests. Bushwillows , Wattle, False Mahogany, were discovered to grow naturally in the area. It is now the leading tree in the area, with the highest density.  

Fauna
Since Hat Wanakon National Park is responsible for both land and water animals found were classified according to their habitats  as follows:
Land animals
1. Mammals: Hat Wanakon National Park has a small area and few naturally occurring forests, making it rare to see large animals. Sightings included Burmese Hare <i> (Lepus peguensis) </i>, Small Asian Mongoose <i> (Herpestes javanicus) </i>, Common Jackal <i> (Canis aureus) </i>, and Grey-Bellied Squirrel <i> (Callosciurus caniecps) </i>.
2. Avian Fauna: Most of them are endemic birds <i> (Avian Fauna) </i> such as Red-Wattled Lapwing <i> (Vanellus indicus) </i>, White-Breasted Waterhen <i> (Amaurornis phoenicurus) </i>, Asian Barred Owlet <i> (Glancidium cusculoides) </i>, Blue Jay <i> (Coracias benghalensis) </i>, Green-Billed Malkoha <i> (Phaenicophaeus tristis) </i>, Greater Racket-Tailed Drongo <i> (Dicrurus paradiseus) </i>, and Red Junglefowl <i> (Gallus gallus) </i>, as well as migratory birds such as the Hill Myna <i> (Gracula religiosa) </i>, Garganey <i> (Anas querquedula) </i> , and Chinese Pond Heron <i> (Ardeola bacchus) </i>, which are found in winter.
3. Reptiles: consist of Malayan Pit-Viper <i> (Calloselasma rhodestomo) </i>, Many-Lined Sun Skink <i> (Mabuya multifasciata) </i>, Butterfly Lizard <i> (Leiolepis belliana) </i>, King Cobra <i> (Ophiophagus Hannah) </i>, Reticulated Python <i> (Python reticulates) </i>, and Golden Tree Snake <i> (Chrysopelea ornate) </i>.
4. Amphibians: Frogs and Toads are found in the park area, while other species have not been explored. (Details in Table 2)

Aquatic animals can be divided into the following categories:
1. Fresh Fish are limited in number due to the location. The most common freshwater fish are Catfish, Snakehead, Carps, and small fish.
2. Sea animals can be divided into the following four groups:
2.1 Most of the sea fish found along the coast are edible fish such as the Diamond-Scaled Grey Mullet <i> (Muail dussumeri) </i>, and Sting ray. There are also inedible fish, such as the Porcupine Fish, Goby <i> (Batrachus grunniens) </i>, and Mini Goby <i> (Ctenogobiops crocineus) </i>.

2.2 Fish that are found in the sea or along coral reefs are mostly large fish or beautiful fish such as Blue-Spotted Fantail Ray <i> (Taeniura lymma) </i>, Redcoat Squirrelfish <i> (Holoceentrus rubrum) </i>, Copperband Butterfly <i>(Chelmon rostratus) </i>, Indo-Pacific Sergeant <i> (Abudefduf bengalensis) </i>, Pink Anemone <i> (Amphiprion penideraion) </i>, and Quoy Parrotfish <i> (Scarus quoyi) </i>.
2.3 Corals can be seen around islands in the park's responsible area, such as <i>Pocillopora damicornis, Acropora formosa, Acropora hyacinthus, Astreopora ocellata, Pavana lata, Fungia fungites, and Porites lutea. </i>

Other sea creatures seen along the beach include Oysters, Green Mussels <i> (Mytilus viridis) </i>, Wedge Shells <i> (Donax faba) </i>, <i>Poker chip Venus, Matuta banksii,</i> Ghost Crab, Cuttlefish <i> (Sepia pharaonis) </i>, Bicolor Pen Shell <i> (Pinna nobilis) </i>, and <i> Cymbiola nobillis</i>, mammals such as <i>Neophocaena phocaenoides</i> may also come to feed near the beach.

Ecological and Genetical Significances
Hat Wanakon National Park has both landl and marine animal habitats, making it ideal for studying the differences between the two ecosystems. The land ecosystems can be studied along the nature trails and the marine ecology can be studied on boats or by diving at the coral reefs at Ko Chan and Ko Tai Si.