The internet or encyclopedia is a good source for this, though the host institution will probably supply a list of recommended clothes. Many countries near the equator are very warm. However, some communities can be cool if they are in the mountains. The International Programs Office has resources on each country including the type of clothes worn. Try to talk with other people who have lived or visited in your host country.
Some countries are casual and one dressy outfit, at most, is needed.
Other countries place more emphasis on dressing nicely, especially regarding women's clothes. Skirts may be more acceptable for women. In Latin America, the Middle East, and some conservative countries, women do not wear shorts. If you choose to wear your own clothing rather than adapt to the customs of the country, you may invite unwanted advances by the opposite sex. You may wash your own clothes.