Photo: François de Dijon · CC BY-SA 4.0Winter nights in Petit-Mars are milder than in 74% of mainland French towns
On a normal July day the thermometer tops out near 25.6°C. Warm afternoons come less often than in 63% of mainland French towns. Temperatures cover 23°C across the year, low to high. Frost greets about 37 mornings a year, so leave time to clear the car.
Figures from Météo-France’s Nort-sur-Erdre station, 5.3 km north-west.
A year in Petit-Mars at a glance
Each month’s typical high and low in °C, at the Nort-sur-Erdre station.
What a year in Petit-Mars feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Nort-sur-Erdre.
About 760 mm of rain a year
December is the wettest month and July the driest. About 23 days a year bring 10 mm or more. 99th wettest of 133 towns of 2,500+ in Loire-Atlantique.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Nantes-Bouguenais
37 frosts and 55 days of 25°C a year
On about 37 nights a year the air drops to 0°C or below, and on about 1 days it stays below freezing all day. About 55 days a year reach 25°C, and 14 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Nort-sur-Erdre: a frost is a night of 0°C or below, a summer day (jour d’été) 25°C or more, a hot day (forte chaleur) 30°C or more.
The Météo-France station at Nort-sur-Erdre
Nort-sur-Erdre is 5.3 km north-west of Petit-Mars. Every figure on this page is the station’s, not a measurement in Petit-Mars itself.
| Station (Météo-France number) | Nort-sur-Erdre (44110002) |
| Distance from the town | 5.3 km north-west |
| Station altitude | 13 m |
| Town altitude (its center) | 12 m |
| Period | 1991–2020 |
| Sunshine measured at | Nantes-Bouguenais, 30 km away |
TownRatings matches each commune to one station with at least 24 years of temperature and rain records: the nearest, counting every 100 m of height difference as 10 km, never across the sea.
How Petit-Mars compares
Against the 4,385 towns of 2,500 or more in mainland France, each read from its own matched station. The dots are the other towns of 2,500+ in Loire-Atlantique.
Nearby towns’ climate
The nearest towns of 2,500+ within 29 km. Where a neighbor uses the same station its figures are the same: the differences you’d feel over a few kilometers aren’t in the normals.
| Town | Station | July high | January low | Rain a year |
|---|---|---|---|---|
| Petit-Mars | Nort-sur-Erdre | 25.6°C | 3.0°C | 760 mm |
| Saint-Mars-du-Désert 5 km | same station | 25.6°C about the same | 3.0°C about the same | 760 mm |
| Les Touches 5.4 km | same station | 25.6°C about the same | 3.0°C about the same | 760 mm |
| Ligné 5.4 km | same station | 25.6°C about the same | 3.0°C about the same | 760 mm |
| Nort-sur-Erdre 5.9 km | same station | 25.6°C about the same | 3.0°C about the same | 760 mm |
| Casson 7.8 km | same station | 25.6°C about the same | 3.0°C about the same | 760 mm |
| Sucé-sur-Erdre 8.1 km | same station | 25.6°C about the same | 3.0°C about the same | 760 mm |
Petit-Mars weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Nort-sur-Erdre station; sunshine at Nantes-Bouguenais.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 9.2°C | 3.0°C | 6.1°C | 82 mm | 73 |
| February | 10.4°C | 2.6°C | 6.5°C | 63 mm | 102 |
| March | 13.4°C | 4.1°C | 8.8°C | 55 mm | 147 |
| April | 16.3°C | 5.4°C | 10.9°C | 58 mm | 183 |
| May | 19.8°C | 8.8°C | 14.3°C | 55 mm | 203 |
| June | 23.4°C | 11.6°C | 17.5°C | 48 mm | 213 |
| July | 25.6°C | 13.2°C | 19.4°C | 42 mm | 229 |
| August | 25.8°C | 13.2°C | 19.5°C | 44 mm | 233 |
| September | 22.6°C | 10.7°C | 16.7°C | 60 mm | 199 |
| October | 17.6°C | 8.8°C | 13.2°C | 81 mm | 123 |
| November | 12.7°C | 5.4°C | 9.1°C | 86 mm | 91 |
| December | 9.7°C | 3.3°C | 6.5°C | 87 mm | 78 |
| Year | 17.2°C | 7.5°C | 12.4°C | 760 mm | 1,873 |
Where Petit-Mars’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Nort-sur-Erdre, 5.3 km away: statistics for 1991–2020.
- Which station: among stations with at least 24 of the 30 years of temperature and rain, the nearest to the commune’s population-weighted center, counting each 100 m of height difference as 10 km; mainland towns use mainland stations and each overseas département its own.
- Altitudes: the town’s from IGN’s RGE ALTI® at its population-weighted center; the station’s from Météo-France.
- Sunshine: the nearest station with at least 10 years of sunshine records, Nantes-Bouguenais, 30 km away.
- Comparisons: every town of 2,500 or more in mainland France, read the same way; the dots are the towns of 2,500+ in Loire-Atlantique.
Météo-France fiches climatologiques · IGN RGE ALTI®. Licence Ouverte 2.0.
Questions about Petit-Mars’s climate
How warm does Petit-Mars get in summer?
August is the warmest month, with average highs of 25.8°C. About 55 days a year reach 25°C, fewer than 63% of mainland French towns, and about 14 reach 30°C.
How cold does Petit-Mars get in winter?
February nights average 2.6°C. The air drops to 0°C or below on about 37 nights a year, and about 1 days a year stay below freezing all day.
How much rain does Petit-Mars get?
About 760 mm a year, more than 52% of mainland French towns. December is the wettest month (87 mm) and July the driest (42 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Nantes-Bouguenais (30 km away), averages 1,873 hours of sunshine a year.
Are these figures for Petit-Mars itself?
No: they are the normals of the Météo-France station matched to Petit-Mars, Nort-sur-Erdre, 5.3 km away. France publishes its climate normals by station, not by commune; a valley, a hill or the sea can make a difference over a few kilometers.
Where do these figures come from?
Météo-France’s fiches climatologiques: 30-year averages (1991–2020) for each of its long-running stations, published as open data since 2024. They are normals, not a forecast.
Source: Météo-France, fiches climatologiques, 1991–2020 statistics (station NORT-SUR-ERDRE, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Petit-Mars →
Contains public sector information under the Licence Ouverte / Open Licence 2.0 (Etalab): INSEE, DGFiP, the Interior Ministry’s statistics service (SSMSI), the Ministry of Education (DEPP), the Health Ministry’s statistics service (DREES) and the Housing Ministry (Carte des loyers). Commune boundaries: IGN Admin Express.