Warm afternoons come to Lagny-le-Sec less often than to 72% of mainland French towns
The depth of winter brings overnight lows near 2.3°C. By rainfall alone, it ranks drier than 70% of mainland French towns. Of all months, December brings the most rain and April the least. An umbrella earns its place on about 116 days a year with 1 mm of rain or more.
Figures from Météo-France’s Roissy station, 17 km south-west.
A year in Lagny-le-Sec at a glance
Each month’s typical high and low in °C, at the Roissy station.
What a year in Lagny-le-Sec feels like
Typical highs and lows by season and by month, from Météo-France’s 1991–2020 normals at Roissy.
About 694 mm of rain a year
December is the wettest month and April the driest. About 19 days a year bring 10 mm or more. 7th wettest of 59 towns of 2,500+ in Oise.
Rain by month
Millimeters
33 frosts and 47 days of 25°C a year
On about 33 nights a year the air drops to 0°C or below, and on about 5 days it stays below freezing all day. About 47 days a year reach 25°C, and 11 reach 30°C.
Day counts are Météo-France’s 1991–2020 normals at Roissy: 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 Roissy
Roissy is 17 km south-west of Lagny-le-Sec. Every figure on this page is the station’s, not a measurement in Lagny-le-Sec itself.
| Station (Météo-France number) | Roissy (95527001) |
| Distance from the town | 17 km south-west |
| Station altitude | 108 m |
| Town altitude (its center) | 106 m |
| Period | 1991–2020 |
| Nearest station of any kind | 2.4 km |
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 Lagny-le-Sec 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 Oise.
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 |
|---|---|---|---|---|
| Lagny-le-Sec | Roissy | 25.1°C | 2.3°C | 694 mm |
| Le Plessis-Belleville 1.7 km | same station | 25.1°C about the same | 2.3°C about the same | 694 mm |
| Saint-Pathus 3.7 km | same station | 25.1°C about the same | 2.3°C about the same | 694 mm |
| Dammartin-en-Goële 5.5 km | same station | 25.1°C about the same | 2.3°C about the same | 694 mm |
| Othis 5.6 km | same station | 25.1°C about the same | 2.3°C about the same | 694 mm |
| Saint-Mard 6.2 km | same station | 25.1°C about the same | 2.3°C about the same | 694 mm |
| Saint-Soupplets 6.9 km | same station | 25.1°C about the same | 2.3°C about the same | 694 mm |
Lagny-le-Sec weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Roissy station.
| Month | High | Low | Mean | Rain |
|---|---|---|---|---|
| January | 7.0°C | 2.3°C | 4.7°C | 57 mm |
| February | 8.2°C | 2.3°C | 5.3°C | 48 mm |
| March | 12.2°C | 4.5°C | 8.3°C | 50 mm |
| April | 15.8°C | 6.7°C | 11.2°C | 48 mm |
| May | 19.3°C | 10.0°C | 14.6°C | 67 mm |
| June | 22.6°C | 13.1°C | 17.8°C | 62 mm |
| July | 25.1°C | 15.1°C | 20.1°C | 60 mm |
| August | 25.1°C | 15.0°C | 20.1°C | 58 mm |
| September | 21.1°C | 12.1°C | 16.6°C | 50 mm |
| October | 16.2°C | 9.2°C | 12.7°C | 60 mm |
| November | 10.7°C | 5.4°C | 8.1°C | 60 mm |
| December | 7.5°C | 2.9°C | 5.2°C | 75 mm |
| Year | 15.9°C | 8.2°C | 12.1°C | 694 mm |
Where Lagny-le-Sec’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Roissy, 17 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.
- Comparisons: every town of 2,500 or more in mainland France, read the same way; the dots are the towns of 2,500+ in Oise.
Météo-France fiches climatologiques · IGN RGE ALTI®. Licence Ouverte 2.0.
Questions about Lagny-le-Sec’s climate
How warm does Lagny-le-Sec get in summer?
July is the warmest month, with average highs of 25.1°C. About 47 days a year reach 25°C, fewer than 72% of mainland French towns, and about 11 reach 30°C.
How cold does Lagny-le-Sec get in winter?
January nights average 2.3°C. The air drops to 0°C or below on about 33 nights a year, and about 5 days a year stay below freezing all day.
How much rain does Lagny-le-Sec get?
About 694 mm a year, less than 70% of mainland French towns. December is the wettest month (75 mm) and April the driest (48 mm).
Are these figures for Lagny-le-Sec itself?
No: they are the normals of the Météo-France station matched to Lagny-le-Sec, Roissy, 17 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 ROISSY, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Lagny-le-Sec →
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.