Monarch Butterfly Sightings

Each year, monarch butterflies make one of the longest migrations in the insect world — traveling thousands of miles between their overwintering grounds in central Mexico and their summer breeding range across North America. This chart overlays weekly temperature data with reported monarch sightings across four representative years, letting you watch the migration unfold week by week and see how shifting temperatures track with the butterflies' movement north in spring and south in fall.

2002
2007
2012
2017
←→ step through weeks  ·  ↑↓ jump between years
Year 2002Week 01
Debug
3.20
0.45
0.90
0.00
0.30
0.00

1.50
1.25

0.90
-93.5
39.0
0.70
dotSize=3.20 latScale=0.45 curve=0.90 shape=hex palette=spectral opacity=0.30 fade=0.00 stroke=#ffffff strokeW=0.00 fillOverride=false fill=#4c78a8 sightShape=circle sightFill=#f6f5f4 sightStroke=#1c71d8 sightStrokeW=1.50 sightSize=1.25 mapScale=0.90 lon=-93.5 lat=39.0 aspect=0.70