The Flower Calendar
When wild plants flower in France, and how that calendar shifts with warming temperatures.
Phenology, the study of seasonal cycles in nature, is one of the most sensitive indicators of climate change. Across France, thousands of citizen observations record each year the first flowering dates of wild plants. Visualised on a circular calendar, these data reveal the beauty of natural rhythms and, in their slow drift, the quiet imprint of warming temperatures.
The calendar brings together twelve wild species common across France: from blackthorn and wild daffodil, among the first to flower at the end of winter, to heather, which opens in late summer. For each species and each decade, the date shown is the median day of the year on which its first observation was recorded, computed from several thousand GBIF occurrences per decade; the range shown around that date (10th to 90th percentile) gives a sense of its year-to-year variability.