So the applet was finally successful today. I had ignored it since yesterday when I created another trial applet to try sending the current temperature to a numeric variable. Neither worked yesterday. Both worked today.
In retrospect, I'm wondering if there was a glitch with IFTTT. I attempted to test the applets multiple times in the past few days as I was creating them. The check now button resulted in a banner across the web browser window saying "check complete" but it would still show that the applet had never been run.
Who knows. But worked today.