Climate & Pressure
Temperature gradually decreases as you go lower into the sea. So temperatures in the deepest ocean trenches are close to freezing point. Each of the 37 trenches have different climates and pressures. For example, water temperatures at Marina range from 34-39 Degrees F while the Trench Le Morne Mauritius 23 Degrees F. As opposed to temperatures, pressure increases as depth increases. On the bottom of trenches it would feel as if 8 tons per sq inch of pressure is on your shoulders.
Location
Ocean Trenches are all over the world, but are mostly found along the margins of the Pacific Ocean. This is because the majority of subduction activity takes place here. All the activity there is what gave this area the name "Ring of Fire". Ocean Trenches also exist along the eastern Indian Ocean, the Atlantic Ocean, and the Mediterranean Sea.