How do you feel about setting your request values right there inline?
STATIC
<button hx-get="/my/weather/data"
hx-trigger="click"
hx-vals='{"location": "01245"}'>
Click for weather in one static location
</button>
DYNAMIC
<button hx-get="/my/weather/data"
hx-trigger="click"
hx-vals='js:{location: document.getElementById("zipcode").value}'>
Click for weather in one static location
</button>
OR
<button hx-get="/my/weather/data"
hx-trigger="click"
hx-vals='js:{location: someJavascriptCalculationFunction()}'>
Click for weather in one static location
</button>