Why a Single Score Matters
You have a free weekend coming up. You're willing to fly somewhere in Europe for two days of sun. So you open a weather app and start checking cities. Barcelona — looks decent. Split — maybe. Lisbon — hard to tell. Athens — wait, is 30% precipitation a lot?
After twenty minutes and six browser tabs, you still don't have an answer.
This is the problem we built LastMinuteSun to solve. Raw weather data is abundant, but it's not actionable. A forecast that says "22 degrees, partly cloudy, 15% chance of rain" doesn't tell you whether that's a good weekend destination or not. And comparing that across dozens of cities manually is a task nobody enjoys.
Our approach is straightforward: we take multiple weather data points for 1,500+ European cities, compress them into a single score from 0 to 10, and rank every destination so you can make a decision in seconds instead of hours.
Here's exactly how that score is calculated.
The Five Factors
Every weather score is built from five measurable factors. Each one contributes a weighted share to the final number. We chose these five because they capture what actually matters for a short leisure trip — not what matters to a farmer or a pilot, but what matters to someone who wants to sit on a terrace, walk through a city, or spend a day at the beach.
1. Sunshine Hours (~30% weight)
This is the single most important factor in the score, and it's the reason LastMinuteSun exists. Sunshine hours measure how many hours of actual, direct sunshine are forecasted for a given day — not just "daytime hours" but hours where the sun is visibly shining.
Why does this carry the most weight? Because sunshine is what people are chasing. You can tolerate 19 degrees if the sun is out. You can forgive a brief afternoon cloud. But a weekend of grey, even if it's technically dry and warm, doesn't feel like a getaway.
We pull forecasted sunshine duration data and normalize it against the maximum possible sunshine hours for that location and time of year. A city near the Arctic Circle in April has fewer potential sunshine hours than one in the Mediterranean, and the scoring accounts for that.
2. Temperature (~25% weight)
Temperature scoring is based on a comfort curve, not a linear scale. The sweet spot sits between 18 and 28 degrees Celsius. Within that range, scores are high. Below 18, the score drops gradually — 15 degrees is still fine for city walks, but 8 degrees is not what most people are looking for on a spontaneous weekend trip. Above 28, the score also starts declining. Extreme heat (35+) can be just as limiting as cold when it comes to enjoying a destination.
This curve-based approach means a city at 23 degrees scores higher than one at 33 degrees, which matches what most travelers actually prefer. If you're specifically chasing heat, the temperature data is always visible alongside the score so you can make your own call.
3. Precipitation Probability (~20% weight)
Rain probability is the most straightforward factor: what are the chances it rains during your visit? Lower is better, and the relationship is fairly linear — 5% is great, 30% is acceptable, 70% means you'll probably need an umbrella more than once.
We look at precipitation probability across the full weekend window rather than just daily averages. A city with 0% chance on Saturday and 60% on Sunday scores differently than one with a steady 30% across both days, because the distribution matters for trip planning.
4. Cloud Cover (~15% weight)
Cloud cover and precipitation are related but not identical. Plenty of days are dry but overcast — technically rainless, practically grey. If you've ever spent a weekend in a coastal city under a thick marine layer, you know the difference between "no rain" and "sunshine."
We measure forecasted cloud cover as a percentage of sky coverage. Clear skies (under 20% coverage) score highest. Broken clouds (40-60%) still score reasonably well — scattered clouds with sunshine between them can make for beautiful conditions. Full overcast (80%+) drags the score down significantly.
This factor is separate from precipitation because a dry, overcast weekend and a dry, sunny weekend are fundamentally different experiences.
5. UV Index (~10% weight)
The UV index might seem like an odd inclusion, but it serves as a useful proxy for overall solar intensity. A moderate UV index (3-6) correlates with pleasant outdoor conditions: enough sun to feel warm and bright, but not so intense that you're forced into shade every fifteen minutes.
Very low UV (0-2) usually indicates heavy cloud or weak sun — not ideal for a sun-chasing trip. Very high UV (8+) means you'll burn quickly and outdoor comfort drops, especially during midday hours. The UV factor gives a small but meaningful boost to destinations where solar conditions are genuinely enjoyable.
At 10% weight, UV never dominates the score. It acts as a tiebreaker and refinement layer.
How the Score Works
The five weighted factors combine into a single number on a 0 to 10 scale. Here's what the ranges mean in practice:
8-10 — Excellent. Clear skies, comfortable temperatures, minimal rain risk. These are the destinations where you can confidently book a flight and leave the umbrella at home. Beach days, rooftop dinners, long walks — all on the table.
6-7 — Good. Solid conditions with minor imperfections. Maybe some afternoon cloud, or temperatures slightly outside the sweet spot. Still a worthwhile trip, especially if you're flexible about activities. Most travelers would be happy with a 6-7 weekend.
4-5 — Mixed. Could go either way. You might get lucky with a beautiful Saturday and a rainy Sunday, or you might get two mediocre days. These scores suggest having indoor backup plans ready.
0-3 — Poor. Heavy rain, cold temperatures, overcast skies, or some combination. Unless you have a specific reason to visit (concert, event, family), these destinations aren't your best bet for a spontaneous sun trip. Stay home, make soup, try again next weekend.
The scores update as new forecast data comes in, so a city's score on Monday for the coming weekend may shift by Thursday as the forecast sharpens.
The Relative Sunshine Score
Raw scores are useful, but we think the most powerful feature of LastMinuteSun is the comparative view. We don't just tell you "Malaga scores 8.4 this weekend." We tell you "Malaga gives you 6 more sunshine hours than Amsterdam this weekend."
This is the relative sunshine score, and it reframes the decision entirely.
If you live in Amsterdam and your home forecast shows 3 hours of sunshine over the weekend, a destination with 9 hours isn't just "sunny" in the abstract — it's a concrete upgrade. Six additional hours of sun. That's the difference between spending Saturday indoors and spending it outside.
The relative approach also helps with less obvious discoveries. You might not think of Ljubljana or Thessaloniki as weekend trip destinations, but if they're offering 8 more sunshine hours than your home city for a fraction of the cost of Ibiza, that's valuable information.
Every city on LastMinuteSun shows both its absolute weather score and the sunshine hour differential compared to major home cities. It turns weather data into a real decision.
Data Sources
Our weather data comes from multiple meteorological APIs. We cross-reference several forecast models to improve reliability and reduce the impact of any single model's bias. When models agree, confidence is high. When they diverge, we weight accordingly and the score reflects that uncertainty.
We focus specifically on the weekend window — Friday evening through Sunday evening — because that's the decision window for spontaneous travel. While we do show broader forecasts, the scoring algorithm is optimized for short-trip planning.
Data refreshes multiple times per day. As a weekend approaches, the forecasts tighten and the scores become more reliable. A score on Monday is a useful signal. A score on Thursday is a strong indicator. A score on Friday morning is about as accurate as weather forecasting gets.
What the Score Doesn't Tell You
Transparency matters, so here's what the weather score deliberately leaves out — and why.
Wind. A windy but sunny day at the beach is a different experience than a windy but sunny day in a sheltered city center. Wind impact is too context-dependent to include in a universal score. We display wind data separately for cities where it matters.
Humidity. Like wind, humidity's impact depends heavily on temperature and personal preference. Thirty degrees at 40% humidity feels very different from 30 degrees at 85% humidity, but baking humidity into the score would overcomplicate a number meant to be glanceable.
Microclimates. Weather scores represent city-level conditions. If you're heading to a specific beach, mountain, or valley within a metro area, local conditions may differ. A score for "Barcelona" represents the city broadly, not Montjuic specifically.
Forecast uncertainty. Weather forecasting is inherently imperfect. Models are good at 1-3 days out, reasonable at 4-5 days, and increasingly speculative beyond that. Our scores reflect the best available forecast data, but they're a guide, not a guarantee. We always recommend checking conditions again the day before you travel.
We'd rather be honest about these limitations than pretend a single number captures everything. The weather score is a decision-support tool — a fast, reliable way to compare destinations and narrow your options. The final call is always yours.
Try it yourself — search your city on LastMinuteSun and see where the sun is this weekend.