It's 9% humidity outside right now. The swamp cooler is basically worthless when the humidity is higher than 25-30%, I think. I haven't charted it or anything so I'm not positive but I think that's about right.
We have five seasons which includes two summers. First summer is dry summer, which is March-June-ish, when humidity starts out low (sometimes down to 1% which KILLS me) and slowly increases. Swamp coolers do okay in March and become increasingly ineffective as it gets closer to July.
Second summer is wet summer, July-ish through October. The temps don't really come back down to normal until after Halloween although you can usually start going outside again in October. You're basically stuck inside from May-October.
It's like winter in the north when you're stuck inside for six months but the opposite, here you're stuck inside for spring-fall and you go outside fall-winter. It's a weird way to live. You lose half the year, every year. I don't understand why people like it but to each their own.
Second summer is more humid. We get rain in July and August. It gets so hot and humid that you can't stand it and then in finally rains. But it has only rained once so far this summer. That's dry for second summer. I don't know why the humidity has dropped so much today, it's unusual but I'm grateful since it means the swamp cooler is a little more effective.
August is also tarantula season (no, I'm not kidding).