The best time to ride the Loire à Vélo is early autumn: September and October have more dry, mild days than summer, and the wind along the valley in these months is so weak that you can choose your direction based on train tickets and overnight stops. Summer is the other way round: the westerly wind off the Atlantic picks up and blows straight into the face of anyone riding towards the ocean. So if you are going in July or August, it makes sense to start on the coast at Saint-Brevin-les-Pins and work your way upriver to Cuffy.
September and October versus July
A good day on the site means less than 1 mm of rain between 9.00 and 18.00 and a high between 10 and 30 °C. In September 78% of days qualify, with only 17% rainy days (≥ 1 mm) and an average high of 22 °C; in October 76% are good days, but daylight is already noticeably shorter. Spring comes close behind: April scores 75%. June remains the best summer month at 71%. July gives 69%, and on 16% of days the heat reaches 30 °C or more; it is also the month when the headwind towards the ocean is strongest, averaging −4.9 km/h (−4.4 km/h in August). A strong headwind above 15 km/h blows for 16% of hours in July for riders heading to Saint-Brevin-les-Pins, but only 3% for those heading to Cuffy.
Direction, stages and route length
In 9 months out of 12, the better direction is Saint-Brevin-les-Pins → Cuffy, that is, upstream from the ocean. This matches the advice on the official France Vélo Tourisme website to start from the coast. In September and October the average wind along the route is below 2 km/h, and the site rates the direction “either way”. One exception within the route: on the final stage Saumur → Saint-Brevin-les-Pins, 200 km long, even in September the wind blows against anyone riding towards the sea: −2.4 km/h.
The site counts 589 km: the main line of the OpenStreetMap track from Cuffy to Saint-Brevin-les-Pins without variants or loops. The official site loireavelo.fr quotes 900 km because it includes the variants. The line is split into 4 stages, listed in the table below the article; these are stretches between towns, not daily rides. Loire à Vélo forms part of EuroVelo 6, and this cycle route has its own page with the same calculation.
Wind data is taken at 10 m above ground in a grid cell of about 25 km: in the sheltered valley at saddle height it is weaker, on the coast near Saint-Brevin-les-Pins stronger. All the figures describe the climate over 2006–2025, not a forecast for your particular week (see the climate block further down the page); the methodology explains how they were calculated.
Planning takeaway: September or October, with the direction chosen for logistics; if only summer works, go for June, and in July and August start from the ocean.