Support hemisphere-based season colors.
Work on season aggregate bands.
Break up x-axis generation into smaller functions for clarity.
Work on sum line toggle and hemisphere toggle.
Fix redisplay of units after toggling layers.
Rotate icon when toggling range.
Start on interactive range change support.
Hmm, local time on DST offset causes formatting problems.
Work on supporting changing node IDs at runtime, and thus the available sources.
Change default to Hour.