Trevelin ground for long periods of time. Winters are stormy with frequent rain, sleet and snow while summers are cool, windy and relatively dry. Mean annual precipitation is . The precipitation pattern resembles a Mediterranean one, where most (75%) of the precipitation is concentrated from April to August, the cooler months with a dry period from September to March. Snowfall can occur during the colder months while rainfall predominates in warmer months; hail rarely occurs. The mean temperature in Trevelin ranges from in July, the coldest month to in January, the warmest month. Frosts can occur at anytime, even in summer,
Hail . GR is derived from the French word grêle. Smaller-sized hail, as well as snow pellets, use the coding of GS, which is short for the French word grésil. Terminal velocity of hail, or the speed at which hail is falling when it strikes the ground, varies. It is estimated that a hailstone of in diameter falls at a rate of , while stones the size of in diameter fall at a rate of . Hailstone velocity is dependent on the size of the stone, friction with air it is falling through, the motion of wind it is falling through,