[OC] Evaporative cooler performance during a heat wave

How do evaporative coolers perform on hot days and does humidity influence them?

It's a question I often see, so with a hot day in Melbourne, we tracked some data. We're in a rental so don't have split system options.

Outdoor vs indoor temps seemed to average around 12 degress celcius, with the largest gap being 16 degrees. Temperature indoors only increased and decreased by 1 degree each hour (up or down), despite larger swings outdoors, suggesting a buffering effect.

It's harder to gauge how much humidity affects the performance: if we take two time points: 10am (33 deg + 22 deg @ 24$ humidity) vs 5pm (42.5 deg + 26.5 dev @ 1% humidity), we see that at higher humidity there's a 11 degrees differential, and at almost no humidity there's a 16 degree differential. So a potential swing of 5 degrees based on humidity, but maybe I need more data to prove that link.