The forecast on your phone might say "8°C, light rain". That tells you almost nothing about whether a narrow ridge is a good idea. What matters is how hard the wind is blowing, where the cloud is sitting, and how likely you are to get wet. Read those three things properly and you can choose a route that fits the day rather than fighting it.

Wind First, Temperature Second

Wind is the single biggest factor in a hill day. A still, cold morning is far easier than a mild one with a gale. Look at the average speed and the gust speed. Gusts are what knock you off balance, and on exposed ridges they can be 50% higher than the average.

• Under 20 mph: barely noticeable on most ridges. A good day for exposed ground.
• 20–35 mph: hard work into a headwind. Balance starts to matter on rocky sections.
• 35–50 mph: difficult. Walking becomes a fight, and you will tire quickly.
• Over 50 mph, or gusts over 60 mph: time to change plans. Ridges and summits are out; low-level routes are the sensible choice.

Direction matters as much as speed. A westerly means the windward slopes catch the rain first and the lee slopes are drier. An easterly in winter brings a raw, penetrating cold. And always check the feels-like temperature: 4°C with a 40 mph wind feels closer to -5°C. That is the number your body will actually experience.

Cloud Base And What It Means For Your Route

Cloud base is given in metres above sea level, and it tells you where the views stop. If the forecast cloud base is 600 metres and your summit is 900 metres, you will spend the top third of the walk in grey, damp clag. That is not a reason to stay home, but it is a reason to have a compass and a map you can actually use.

If the cloud base is forecast at 1,000 metres and your high point is 950 metres, you might get lucky with clear summits. Be careful, though: cloud base is an average, and local topography can pull it down. A ridge that funnels moist air can be in cloud when the valley is sunny. For route choice, ask a simple question: does my route rely on views or on navigation? If it relies on views, and the cloud base is below your high point, choose a lower line or a valley walk.

Precipitation: Probability, Timing And Intensity

"Chance of rain" is often the least useful number in a forecast, because 30% might mean a brief shower or a soaking, depending on the day. Look at the timing and intensity instead. A front arriving at 2pm means you can be off the tops by lunchtime. A front parked over the hills all day means you will be wet whatever you do.

• Showers: usually short and sharp. You can often dodge them, but they can be heavy and cold.
• Frontal rain: steady, widespread, and long-lasting. It soaks everything and reduces visibility.
• Timing: a 70% chance at 6am and 20% by 11am is better than the reverse.

In winter, check the freezing level. If the freezing level is 700 metres and you are heading to 900 metres, expect ice on the path and rime on the rocks. That changes your kit and your pace.

Temperature, Freezing Level And Inversions

Air temperature is worth a glance, but only alongside wind. A still day at 2°C is manageable with good layers. A windy day at 6°C can feel far worse. Add rain, and the combination of wet and windy is the classic hypothermia recipe.

Temperature inversions are a bonus: on a calm winter morning, the valleys can be filled with cold fog while the tops are clear and mild. If the forecast mentions an inversion, a high route may be warmer and sunnier than a low one. But inversions often come with poor valley visibility, so navigation from the car park can be tricky.

Making The Call: Ridge Or Valley?

Put it all together. Imagine a forecast with 25 mph winds gusting 40, cloud base at 700 metres, and a 40% chance of showers. A lower ridge with plenty of escape routes is a good call. The summit might be in cloud, but you can turn around easily and the wind is manageable.

Now try 45 mph winds gusting 70, cloud base at 400 metres, and 90% chance of heavy rain. A high ridge is a bad idea. A valley circuit or a low-level forest walk is the sensible choice. The hills will still be there next week.

Finally, match the forecast to the group. A strong, experienced walker might manage a 35 mph wind on a familiar ridge. A tired group, or someone new to the hills, will struggle. Be honest about who is out with you. The best forecast reading is the one that gets everyone back safely.

Three Checks Before You Leave The Car Park

• Read the forecast again: the overnight update often changes the timing of rain and the wind speed.
• Look at the actual conditions: is the cloud base where the forecast said? Are the trees moving more than expected?
• Have a plan B: a lower route, a shorter route, or a different valley. Decide the turnaround time before you set off.