How we score the weather
Every destination on this site carries a number from 0 to 10. That number decides what you see and in what order, so you are entitled to know exactly how it is produced. Here is the whole model, including the parts that make us look bad.
The short version
We score each forecast day on its own, then combine the days into a score for the whole window. We do not average the week and call it a day — averaging is how a travel site turns four grey days and one good one into "sunny".
Step 1 — scoring a single day
Each day gets a 0–10 score built from three things:
- Temp (40%) — how close the day's high sits to a comfortable range. It falls off in both directions: too cold and too hot are both penalised.
- Sky (30%) — derived from the WMO weather code. Clear sky scores highest, then partly cloudy, then overcast, then fog, drizzle, rain, showers and thunderstorms.
- Dryness (30%) — from the day's maximum precipitation probability. We use the maximum, not the average, because the rain that ruins an afternoon does not care what the daily mean was.
The caps
Some conditions are bad enough that no amount of pleasant temperature should rescue the day, so we cap the result outright rather than let the weighting average it away:
- A day with a thunderstorm is capped at 4.0.
- A day at 115°F or hotter, or 45°F or colder, is capped at 5.5 — that is outside the usable range for the kind of trip we sell, whatever the sky is doing.
- Fog, drizzle, rain and showers each carry their own lower cap on top of the sky penalty they already take.
Step 2 — scoring the window
Why one great day cannot carry a week
That middle term is the whole point. A quarter of the window score is set by the worst day in it. If you fly somewhere for five days and one of those days is a washout, the washout drags the score down and stays visible in it — there is no arrangement of good days that can hide it.
The best day in a window gets no special treatment at all. It contributes only through the trimmed mean, alongside every other day. A single spectacular Tuesday does not make the week worth flying for, and the arithmetic here refuses to pretend otherwise.
Why "clear" excludes "partly cloudy"
When we say a window has three clear days, we mean three days the forecast calls clear or mainly clear. Partly cloudy days are not counted as clear. They are perfectly pleasant days and they score well — but calling them clear is the exact sleight of hand that makes weather marketing untrustworthy, so we do not do it.
We also report the count of clear days separately from the score, and never fold it in. The score answers "how good is this week overall?". The clear-day count answers "how much actual sun am I getting?". Those are different questions, and a destination can do well on the first while doing badly on the second. When that happens we show you both numbers side by side rather than the flattering one alone.
A real worked example, from today's data
This is not an illustration. It is read live from the forecast cache that powers the rest of the site, at the moment this page loaded, and it is deliberately the most awkward case we could find in it.
Taos, NM · SAF
What the forecast actually says: 4 cloudy / 3 wet days, no clear days in 7.
Read this before you read the score. Taos scores 6.2 out of 10 and has not one genuinely clear day in the next 7. That is not a bug in the model — it is the model working. The days are dry and the temperature is good, which is what the score is measuring. The sky is grey, which is what the clear-day count is measuring. If you are flying somewhere to sit in the sun, this window is not for you, and no headline number on this site will tell you otherwise.
The days, as forecast
| Date | High | Low | Rain | Sky | Day score |
|---|---|---|---|---|---|
| 2026-08-06 | 93°F | 64°F | 4% | Overcast | 7.8 |
| 2026-08-07 | 91°F | 61°F | 11% | Overcast | 8.0 |
| 2026-08-08 | 94°F | 59°F | 16% | Overcast | 7.3 |
| 2026-08-09 | 93°F | 63°F | 21% | Light drizzle | 6.7 |
| 2026-08-10 | 92°F | 61°F | 34% | Light drizzle | 6.4 |
| 2026-08-11 | 89°F | 57°F | 34% | Overcast | 7.5 |
| 2026-08-12 | 91°F | 59°F | 52% | Light drizzle | 5.7 |
How the sky broke down
- 0 clear or mainly clear
- 0 partly cloudy
- 4 overcast
- 3 wet (fog, drizzle, rain or showers)
- 0 stormy
The model's own working, term by term
- 7 forecast days: 0 clear/mainly clear, 0 partly cloudy, 4 overcast, 3 wet (fog/drizzle/rain/showers), 0 stormy.
- Trimmed mean of day scores 7.1 × 0.55 = 3.93
- Worst day drag: worst day is 5.7 × 0.25 = 1.43 - one bad day cannot be averaged away.
- Longest consecutive run of good days (≥7.0) is 3/7 = 43% coverage × 0.20 = 0.86
- Best single day is 8.0 but it only counts through the trimmed mean - a lone great day cannot carry the window.
- Advertised 3-day window (2026-08-06→2026-08-08) scores 8.1 on its own.
- Legacy gate counted 3/7 days as "perfect sun"; this model counts 0 genuinely clear.
If that example looks unflattering, that is because it is. It was chosen by preferring the highest-scoring destination in the cache with zero clear days, precisely so the uncomfortable case is the one on display. Publishing a scoring model and then illustrating it with your best-looking city is a brochure, not a methodology.
What this score is not
It is a forecast, and forecasts are wrong sometimes. A 9 is not a promise of sunshine and carries no entitlement to a refund if the week turns. What the score does promise is that the same published arithmetic was applied to every destination, that nothing was quietly boosted, and that when the sky is grey we say the sky is grey. The full terms are on our terms page.