Choosing the day for a bike ride based on the weather

On a bike, the weather is about more than “sun or rain”. A lovely day can turn into a slog with a headwind all the way home, while a grey but calm sky can make for an excellent ride. To choose the best day, you need to check the weather in the right place, at the right time and with the right criteria. Here they are.

Check the weather for when you'll be there, not for the start

A three- or four-hour ride passes through several villages, sometimes over a pass, and the weather changes in the meantime. The forecast for the starting town at 9 am says nothing about the shower expected at 11 am up on the plateau. Ideally, you combine the route, the group's pace and the hourly forecast: that's what tells you what the weather will be like at each point when you get there.

The criteria that really matter

Headwind

Wind is often the most underestimated factor. A steady headwind cuts your speed and piles on the fatigue, whereas a tailwind helps rather than hinders. What matters is the wind direction relative to each section of your route, not just its strength. On a loop, try to ride into the wind on the way out, while your legs are fresh, and come home with the wind at your back.

Above an average wind of about 25 km/h, riding becomes noticeably harder whatever the direction: the group struggles to stay together and exposed sections become draining.

Gusts

Gusts are a safety problem more than a fatigue one. A sudden crosswind can push a rider towards the middle of the road or into a neighbouring wheel, especially with deep-section rims, on a descent or on an open ridge. When gusts above 50 km/h are forecast, it's better to choose another day or a sheltered route.

Rain and the risk of showers

Distinguish between two pieces of information: the amount of rain forecast and the probability of rain. A small amount that is very likely often means continuous drizzle. A high probability of showers, say above 40 %, signals a real risk of getting caught out. Rain makes the road slippery, especially on road markings and manhole covers, lengthens braking distances and chills you quickly.

How cold or hot it feels

The displayed temperature isn't enough: on a bike, the wind of your own speed cools the body, and humidity makes heat feel worse. Look at the “feels like” temperature.

• Below about 8 °C feels-like, hands and feet suffer: full-finger gloves, overshoes and a windproof jacket become essential, and descents are freezing.
• Above about 28 °C feels-like, the risk of dehydration rises: set off earlier, plan water stops and ease the pace on the climbs.

Darkness and the start time

In autumn and winter, a very early start or a late return means riding before sunrise or after sunset. Riding in the dark requires front and rear lights and high-visibility clothing, and remains riskier on roads shared with cars. Work out the return time from the distance and the pace, add the breaks, and compare it with the sunset time.

When can you trust the forecast?

Weather forecasts are not equally reliable at every range.

• Two weeks ahead (about 16 days): this is the limit of detailed forecasts. They give a trend, useful for ruling out a clearly unsettled spell, but the hour-by-hour detail still changes a lot.
• One week ahead: the trend becomes clearer. The broad picture, such as a rain front or a windy spell, is generally identified.
• Two or three days ahead: forecasts become reliable enough to decide. This is the right time to confirm the date.
• The day before: check the wind and the risk of showers to adjust the start time or your kit.

The right strategy for a group ride is therefore to suggest several dates early enough for everyone to plan, then decide two or three days beforehand, when the weather is more certain. The guide to organising a group bike ride sets out this method, from choosing the route to the ride-day checklist.

Compare several slots at a glance

Cross-checking by hand the wind direction, rain, feels-like temperature and time of passage on each section of the route, for three or four dates, takes time. Cyclodate works out the weather along your route for each suggested date: from your GPX and the group's pace, it estimates when you'll ride each section and fetches the Open-Meteo forecast for that moment.

The slots are then ranked from most to least favourable, with a label (Excellent, Good, Average or Poor). The ranking takes into account the headwind based on the direction of each section, strong wind, gusts, rain along the way, the risk of showers, how cold or hot it feels and time spent riding in the dark. Forecasts are available about two weeks ahead: for a later date, the page says the weather will come later.

Adapt the ride rather than cancel it

Imperfect weather doesn't necessarily mean staying at home.

• Strong wind: choose a sheltered route, through woods or along a valley, or ride the loop the other way round.
• Showers late in the morning: start earlier or shorten the loop.
• Hot weather: set off in the cool of the morning and pick a route with water fountains.
• Cold: push the start back an hour to make the most of the sunshine and avoid long descents early in the morning.

On a multi-day tour, the weather is handled differently: you're no longer choosing just a date, but the sequence of stages. The guide to planning a multi-day bike trip covers these questions.