Trelew possesses a dry, temperate climate, with winter temperatures varying between a chilly 0°C and 15°C. In spring and fall, temperatures average between 10°C and 20°C, and during the summer, temperatures can reach 38°C.
Trelew hosts several festivals and fiestas during the year, and visitors may wish to plan their ininerary to coincide with at least one of them.
Trelew Eisteddfod, the two-day annual festival celebrating Welsh culture and art is held in mid-October, and attracts more than 1,000 visitors from both Argentina and abroad.
The Certamen Internacional de Coros, held in mid-Septembre of odd-numbered years, draws choirs from all over the world for practice and competition.
La Fiesta Provincial de Pinguino is held on October 20, and welcomes the spring arrival of the penguins at Punto Tombo reserve.
El Aniversario de la Ciudad, which celebrates the town's Welsh foundings, is held on October 20.