Swamp Coolers in Grand Junction: When to Start + How to Prep

It's that time of year in Western Colorado. Do we flip the switch on the swamp cooler, or is there still some snow left in the season? Grand Junction living means warm days, chilly nights, and unpredictable storms, so timing is everything.

Many homeowners throughout the Western Slope rely on evaporative cooling. Call it a swamp box, desert cooler, wet air cooler, evaporative air conditioner, or any other name you like. Before it gets the green light, it's worth checking weather trends, prepping your cooler, and selecting a launch date.

Read More: How Great is the Weather in Grand Junction, Colorado?

What the Weather’s Doing Right Now

The Old Farmer’s Almanac called for a warm spring and summer in Western Colorado—and so far, it’s looking spot on. I saw both my neighbors getting their coolers ready back on April 1st. Normally, we don’t hit the mid-80s until mid-May. But in 2025, Grand Junction already reached 83° on April 11th.

By late April, overnight lows are usually hanging out in the 40s, which means we’re getting pretty close to swamp cooler season. According to Weather.com, we can expect consistent 80-degree days starting the second week of May.

Prepping Your Swamp Cooler the Right Way

Getting your swamp cooler ready for the season takes a little bit of prep beforehand. Before throwing the switch, it's a good idea to run down a checklist similar to the one below to make sure your swamp cooler is ready to go:

1. Uncover and inspect the unit
2. Clean pads or replace them
3. Check the water line & float
4. Inspect the wiring and the belt
5. Test airflow & temperature

You might also run the cooler in fan-only mode to shake off the winter dust before adding water. Of course, crack a window or turn on a ceiling fan to avoid that 'swamp house' scent.

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Selecting A Launch Date

The best day to turn on your swamp cooler depends on your home. If you're still throwing on a hoodie in the morning, it might be a little early to get your cooler going. If the afternoon sun makes your home feel like it's 80 degrees in your house, you might be able to at least set up the cooler for fan-only mode.

When in doubt, you can't go wrong setting a tentative date to make the switch. Mother's Day is usually a safe bet for Grand Junction. A later date will work better for those in Glade Park or Collbran.