Weather Index V2 · 0–100 · higher suits your preference better · historical, not a forecast
Step 1: Score every dayHeat, sun, rain and wind · 0–100
Step 2: Average your tripEvery day and every year counts equally
Step 3: Check past yearsHow often the whole trip was good
What goes in
Feels like10:00–18:00 local, hour by hour
SunshineNone −40 · 8h −2 · 10h 0
RainAmount and wet hours, separately
WindDisruptive daytime wind
Your preference
Comfortable 18–24°C
Warm 24–30°C
Hot 30–34°C
The method
Daily score
Each day starts at 100 and loses points for temperature, sunshine, rain and wind, kept between 0 and 100.
The day is read from 10:00–18:00 local time (daylight saving included), in the intervals between hourly readings.
Temperature and wind: each interval loses its own points, then the day takes their average, weighted by each interval’s length. Hot and cold hours cannot cancel out.
Temperature counts the feels-like degrees outside your range; wind is the speed at 10 m. Sunshine counts the whole local day.
Rain counts only 10:00–18:00: the amount, and separately the wet hours (0.2 mm or more in an hour). 5 mm in one wet hour costs 1 point; over six wet hours, 21.
Targets and penalties are holiday preferences, not scientific standards.
Points lost
Feels-like outside your range
°C
Points lost
0
0
2
3
5
15
8
35
12
60
16
85
20+
100
Sunshine, whole day
Hours
Points lost
0
40
2
30
4
20
6
10
8
2
10+
0
Daytime rain
mm
Points lost
0
0
0.2
0
5
1
10
3
20
8
40+
20
Wet daytime hours
Hours
Points lost
0
0
1
0
2
2
4
10
6
20
8
30
Daytime wind
km/h
Points lost
0
0
15
0
25
2
35
8
45
20
60
50
80
80
100+
100
Past trips
Every year in 2016–2025 counts equally; trips include their first and last day.
“8 of 10 historical trips averaged 85+” counts past trips averaging 85 or more. It is not a probability.
Days scoring 85+: the days in a past trip whose own score reached 85, averaged.
At least eight complete trips and 80% of eligible periods are needed; missing data drops a whole trip.
The worst trip and poor spells (below target, 60 or 40) are shown day by day, in order.
Weather match & best dates
Weather match orders by the Index minus 5 × the share of past trips below 70 (two in ten → −1). The Index shown never changes.
Favourable periods are start dates for your trip length (default 7 days) and may cross New Year.
Stability re-checks each period with one year left out; eight supporting checks are needed. It measures the recommendation, not a chance of good weather.
Score breakdown
Details and destination pages show where a trip’s 100 − Index points went: shared by cause in proportion to its average daily penalties, in whole points. or An up or down triangle after a card’s reading: that cause cost 5 points or more.
The causes are heat above your range, cold below it, sunshine, rain and wind. Each starts as its average daily points over the trip; all are then scaled by one factor so they add up to the points lost, because a day cannot fall below 0.
Charts & month pages
Days, daylight & humidity
Charts and month pages use the Index’s own local days, every year weighted equally, without smoothing.
A month averages its own days; February is 1–28 February. A rain day has 1 mm or more over the local day, snow included.
The Index counts rain only in 10:00–18:00, so an overnight rain day can leave the daytime score untouched.
Feels-like is the 10:00–18:00 median. Hot days: a median above 30°C and 35°C; the second is part of the first. Wind is the 10:00–18:00 maximum.
Daylight is calculated from latitude, sunrise to sunset; it is not observed.
Dew point, from the original daily summaries (UTC days): below 13°C fresh, 13–18°C humid, 18°C+ muggy (NWS guide).
Monthly guides
Where’s hot & where’s dry
Each popular place’s whole month, scored as Explore scores a trip from the 1st to the last day; February is 1–28 February.
Where’s hot: the Hot range (30–34°C). Index 85+, feels like 30°C+, rain on no more than 1 day in 3, and 8 of the last 10 years averaging 85+. Highest Index first.
Where’s dry: the Warm range (24–30°C). 3 or fewer rain days, Index 60+, feels like 18–34°C. Fewest rain days first; a dry year had 3 or fewer in that month.
One place per metro area (25 km), up to 20 a month; a month needs 6. Explore shows the same numbers for the same dates.
Weather data by Open-Meteo and Copernicus ERA5, licensed CC BY 4.0. Scores and summaries are Blenesa’s own.
Limits
Each place reads one ERA5 grid cell, about 25 km across, not a weather station.
A cell that is mostly sea can read like the sea: milder days, warmer nights and a narrow gap between them. A mountain cell can be much wetter or drier than its town.
Short, local showers and storms are smoothed out, so rain days and wet hours are estimates.
10 years show the usual pattern, not every extreme, and never a forecast.
Blenesa’s own model, not a medical or meteorological standard · Find a destination