I was searching for songs about weather when I came across this gem, Signs of the Weather. It’s the perfect piece for practicing part-singing, and the multiple verses provide plenty of opportunity for students to practice both the upper and lower parts.
If you’ve already practiced rounds with your students, I think this song would be great as a follow-up. You might start by having all students sing the upper part in unison. When teaching part-singing, I like to split up the lessons in two different classes. That way, students have a chance to really internalize the melody before attempting to split parts. However, if your classes are particularly long or your students have practiced part-singing before, they may have no problem attempting both parts in one sitting.
Once they can sing the melody (all verses) independently, you can move on to the next step. Start by having them isolate/sing the section “When cold raw winds”. Then, have them listen as you sing the lower part, “Sweep from the north”. Ask them questions such as, “Did you notice any similarities in the upper and lower part?”, “Was the rhythm the same?”, “Were the pitches similar?” If all goes well, your students will immediately hear and see the similarities.
You can follow a similar track with the last three measures of the song. Your students should be able to discern that the first note of the lower part is the same as the upper, and that they both end on the same pitch. I’ve created a video below, which goes through these steps for you.