La Mesa's winters are mild, with temperatures rarely dipping below 0°C and averaging around 13°C in January and December. Spring is a gradual warming period, with April and May temperatures rising to an average of 16-17°C, punctuated by occasional heatwaves up to 35°C. Summer months bring warmer days, with June and July temperatures consistently above 20°C, but without extreme highs. Autumn is marked by a slow cooling trend, with September still averaging around 21°C before dropping to 18°C in October.