Transparent methodology · Human Environmental Comfort Index

How we score environmental comfort.

The Human Environmental Comfort Index (HECI) ranks places using a 5-component model with equal weights (20% each). Each component is scored 0–10 using transparent, evidence-based formulas applied to historical data.

These core components make up the HECI score (0–10, higher = more comfortable).

Thermal Comfort

Air Quality

Sunlight

Rainfall

Disaster Risk

Scoring Components

1. Thermal Comfort (20%)

Based on apparent temperature (feels-like temperature combining air temperature, humidity, wind). We score each daily value then average the scores to properly penalize extreme temperatures.

Optimal

18–24°C = Score 10

Good

12–28°C = Score 7–10

Poor

≤0°C or ≥35°C = Score 0

2. Air Quality (20%)

Based on PM2.5 concentrations converted to US EPA AQI scale. Annual average from daily measurements.

Good

0–50 AQI = Score 8–10

Moderate

51–100 AQI = Score 5–8

Unhealthy

101–150 AQI = Score 3–5

Very Unhealthy

151+ AQI = Score 0–3

3. Sunlight (20%)

Annual sunshine hours. Essential for vitamin D, mood, and seasonal comfort.

Excellent

2500+ hours = Score 10

Good

2000–2500 hours = Score 8–10

Moderate

1500–2000 hours = Score 5–8

Poor

<800 hours = Score 0–2

4. Rainfall (20%)

Annual precipitation. Balanced curve based on livable cities worldwide.

Optimal

600–1400mm = Score 10

Wet but livable

2000–2500mm = Score 6–8

(London, Singapore)

Arid

200mm = Score 4

Extreme

0mm or 5000mm+ = Score 0

5. Natural Disaster Risk (20%)

Based on actual recorded events within 50km radius over past 3 years. Measures recent disaster frequency, not geological or theoretical risk.

Earthquakes

USGS magnitude 4.5+ events

Weather hazards

NASA EONET floods, storms, wildfires, droughts

Scoring

Cumulative exposure mapped to 0–10 scale

Data Sources

OpenMeteo

Weather data (apparent temperature, sunshine, precipitation)

OpenMeteo AQ

Air quality PM2.5 measurements

USGS

Earthquake monitoring data

NASA EONET

Natural disaster event tracking

Validation Results

The scoring system has been validated against real-world climate expectations:

Hot climates

Baghdad (6.7), Dubai (5.8), Cairo (6.6)

Appropriately penalized for extreme heat

Temperate climates

Melbourne (9.2), Curitiba (9.4), Nairobi (9.3)

Highest scores

Wet climates

Vancouver (7.6), London (8.7)

Realistic scores despite high rainfall

Polluted cities

New Delhi (7.5), Beijing (7.4)

Penalized for poor air quality

Technical Implementation

Scoring curves

HECI uses piecewise linear interpolation for smooth, explainable scoring curves.

Historical data

The system processes ~10 years of historical data per location and updates daily.

Open and reproducible

All scoring functions and data sources are open and reproducible.

Sources:Open‑MeteoOpen‑Meteo AQUSGS EarthquakesNASA EONETLast updated: September 2025