Tustin's winters are mild, with temperatures ranging from 2-30°C in January and 5-28°C in December, averaging around 14°C. As spring approaches, temperatures rise gradually, with April being the warmest month so far, averaging 17°C. Summer months see a more consistent temperature range of 16-37°C, peaking in June and July at an average of 22-25°C. Autumn brings a slight drop in temperatures, but still remains pleasant, ranging from 8-34°C in October and November.