How Accurate Is a 7-Day Forecast?
A seven-day forecast is genuinely useful — but not equally at every range. Knowing where the reliable part ends helps you plan without being surprised.
Why accuracy drops across the week
Weather is a chaotic system: tiny uncertainties in today's measurements grow rapidly over time. In practice a next-day forecast is right around 90% of the time for temperature and general conditions, a three-day forecast is still strong, and by day six or seven you are looking at a trend, not a promise. That is why the far end of any weekly outlook — ours included — should be read as "warming up" or "a wet spell coming", rather than an exact figure.
How to use a weekly outlook
- Trust the next 1–2 days for firm plans like what to wear or whether to carry an umbrella.
- Treat days 3–5 as a good steer for loose plans, and re-check closer to the date.
- Read days 6–7 as direction only — the shape of the week, not the detail.
Re-checking the day before always beats relying on a week-old outlook, because each new run folds in fresh observations.
Check the 7-day outlook and re-check it as your plans firm up.
Open the Weather Forecast tool