I need to know what the angle of the sun above the Western horizon is in the afternoons in Denver, CO. Where can I find this out?

The Sun moves back and forth from 1 Solstice to the other Solstice(Summer/Winter). In between is the Equinox(Equal Day/Equal Night).
Can you Give a Day and a Time?
What do you want to find out? Or what for?
StarDate Online | Stargazing Beginner's Guide (http://stardate.org/nightsky/bguide/)

The Sun moves back and forth from 1 Solstice to the other Solstice(Summer/Winter). In between is the Equinox(Equal Day/Equal Night).
Can you Give a Day and a Time?
What do you want to find out? Or what for?
StarDate Online | Stargazing Beginner's Guide (http://stardate.org/nightsky/bguide/)

The reason I'd like to know is because my body temperature drops more than 1 degree F in the late afternoon and it seems to be related to when the sun starts going down below the west horizon and ends almost 2 hrs. later. Today it started at 3:30PM and was over at about 5:30PM. Earlier in the year it started sooner.

Here's a calculator that you can use. You set your position to Denver, pick the date you want, and it plots the sun's altitude above the horizon and azimuth (degrees from true north) throughout the day:
SunPosition Calculator (http://sunposition.info/sunposition/spc/locations.php#1)

Today's plot is shown below.