Guernes

Identity

Guernes (INSEE 78290) is in Yvelines (78), part of CU Grand Paris Seine et Oise. Population 1,085 (2023). ^[1]

INSEE density class: Ceintures urbaines (level 4). ^[2]

Data vintages: INSEE BPE 2025 · INSEE SIRENE 2026-09 · INSEE census (RP) 2023 · INSEE COG 2026 · INSEE density grid 2026.

Permanent link: https://vivantrural.com/en/fr/78290-guernes

Vitality score

Vitality score 33.9/100 — Few services (model fr-v0.2).

Confidence: high.

Better served than 41 % of the 13,843 communes of a similar size.

Compare this with communes of a similar size. The score measures how well a place is served relative to its own size band, and larger communes score higher as a rule — so it reads meaningfully against another village, and misleadingly against a town.

Measured but not scored in this model: Market. See the methodology for why.

Services

A food shop, a school and somewhere to eat or drink. ^[3,4]

1 × Butcher (boucherie). ^[3,4]

1 × Grocery (épicerie / supérette) (GUERNES MARKET). ^[3,4]

1 × Restaurant (STREET GASTRONOMIE). ^[3,4]

1 × Primary school (élémentaire) (ECOLE ELEMENTAIRE). ^[3]

Not counted, because the business register records them as closed: 1 × Butcher (boucherie), 2 × Restaurant.

Not found in the commune: Bakery (boulangerie), Supermarket, Café / bar, Nursery school (maternelle), GP (médecin généraliste), Pharmacy, Post office / agence postale, Library. ^[3,4]

Market and village life

Market day: unknown — nothing found in the datasets or on the commune website.

Trajectory

Population 1,032 (2012) → 1,085 (2023): 5.1 % over 10 years. ^[5,1]

Population 745 (1990) → 1,085 (2023): 45.6 % over 30 years. ^[6,1]

Dwellings (2023): 491, of which 1.8 % second homes and 8.8 % vacant. ^[7]

Access and surroundings

Bakery (Rosny-sur-Seine): 1.2 km to the south (straight line). ^[8]

Food shop (Guernes): 0.1 km to the south-east (straight line). ^[9]

GP (Rosny-sur-Seine): 1.3 km to the south (straight line). ^[8]

Pharmacy (Mantes-la-Jolie): 3.3 km to the south-east (straight line). ^[10]

Primary school (Guernes): 0.1 km to the south (straight line). ^[9]

Climate

An average of 14 days a year at or above 30 °C and 33 days at or below 0 °C, over 29 complete years in 1995–2024. ^[11]

Measured at the MAGNANVILLE weather station, 6 km away at 123 m; the village itself is at 38 m. ^[11]

The village sits 85 m below the station, so each day's reading was shifted by 5.71 °C per km of altitude before the days were counted. Expect the result to be within about 0.68 °C. ^[11]

Muggy days — a dew point at or above 18 °C — average 1 day a summer. ^[11]

Humidity measured at MAGNANVILLE, 6 km away at 123 m, over 30 summers. ^[11]

That station sits 85 m above the village, so each day's humidity was shifted by 4.22 °C per km before the muggy days were counted. ^[11]

An average of 678 mm of rain a year, spread over 113 days — about 6 mm on a day it rains. ^[11]

Rainfall measured at MERICOURT, 2.5 km away at 20 m. Rainfall is not adjusted for altitude: unlike temperature it has no simple gradient to correct by. ^[11]

Uncertainties

No specific uncertainties flagged.

References

1. INSEE census (RP) 2023 — 78290/2023
2. INSEE density grid 2026
3. INSEE BPE 2025
4. INSEE SIRENE 2026-09
5. INSEE census (RP) 2023 — 78290/2012
6. INSEE census (RP) 2023 — 78290/1990
7. INSEE census (RP) 2023 — 78290/logement/2023
8. INSEE BPE 2025 — 78531
9. INSEE BPE 2025 — 78290
10. INSEE BPE 2025 — 78361
11. Météo-France daily climatology 1995-2024