In Ain · Météo-France, fiches climatologiques
Miribel is the hottest city in Ain, at 30.6 days, ahead of Valserhône (26.4 days) and Ambérieu-en-Bugey (25.6 days). At the other end, Gex is the coolest city, at 1.3 days.
| Rank | City | Days above 30 °C | Population |
|---|---|---|---|
| 1 | Miribel | 30.6 days | 10,395 |
| 2 | Valserhône | 26.4 days | 16,712 |
| 3 | Ambérieu-en-Bugey | 25.6 days | 15,934 |
| 4 | Pérouges | 25.6 days | 1,387 |
| 5 | Saint-Genis-Pouilly | 18.8 days | 14,432 |
| 6 | Ferney-Voltaire | 18.8 days | 12,094 |
| 7 | Divonne-les-Bains | 18.8 days | 10,464 |
| 8 | Oyonnax | 18.7 days | 22,480 |
| 9 | Bourg-en-Bresse | 14.2 days | 42,372 |
| 10 | Gex | 1.3 days | 13,627 |
The same ranking for the whole of France : The hottest cities in France · The coolest cities in France in summer
Scope: France, metropolitan and overseas, Corsica and the DROM included. This dataset holds every commune of 10,000 inhabitants or more, plus smaller communes famous enough to be household names, 1,131 in all. It is not the full list of 35,000 French communes, so a village can sit outside a ranking whose extreme it would otherwise hold. This particular ranking is metropolitan only: the distance to the coast is measured against the coastlines of the Hexagon and Corsica, which would put an overseas port thousands of kilometres from a sea it sits on, so no value is published for overseas France rather than a wrong one.
Method and sources: populations are the INSEE legal populations, boundaries and coordinates come from the IGN commune registry, both served by geo.api.gouv.fr. Density is the population divided by the commune's area; distances are measured as the crow flies from the commune's centre. Data read on August 28, 2026.