How the Local Environmental Conditions Index works
The Local Environmental Conditions Index reads the long-run recorded climate of an area and states, on fixed published scales, how demanding those conditions may be for buildings. It describes the local environmental conditions relevant to buildings, never the physical condition of an individual property.
Method status. Local Environmental Conditions Index 1.0 (methodology LBCI 1.0), candidate, pre-ratification. It has not yet been independently reviewed or validated. The settings that review will examine are listed under Independent review, and every result states this status.
What the number means
Each dimension is scored from 0 to 100 on a fixed scale. 100 means the least demand on that scale; a lower number means more demanding recorded conditions. Because the scales are fixed, an area is never ranked against other areas, and its result does not move when another area's data changes.
It is about the area
Milder local conditions do not mean a building is in good condition, and demanding conditions do not mean a building is at fault. The building has its own ICI Score.
It is not community resilience
It does not include infrastructure, power reliability, emergency response, adaptation or recovery capacity. It measures climate demand on buildings only.
It is not a risk score
It is not an insurance, lending, underwriting or property-value measure, and must not be used as one.
It never changes the ICI Score
The two are calculated separately and shown separately.
Dimensions, sources and weights
| Dimension | Measure and source | Scale (100 at the start, 0 at the end or beyond) | Weight | Where available |
|---|---|---|---|---|
| Cold | Heating degree days below 18 °C (Canada: ECCC station normals; United States: NOAA normals, converted from Fahrenheit) | 0 to 10,000 | 2 | Canada and United States |
| Heat | Cooling degree days above 18 °C (same sources) | 0 to 2,500 | 2 | Canada and United States |
| Snowfall | Snowfall, cm a year (ECCC station normals) | 0 to 500 | 1 | Canada only |
| Freeze-thaw | Days a year that cross freezing (NOAA daily normals) | 0 to 200 | 1 | United States only |
| Heavy precipitation | Days a year with 25.4 mm (1 inch) or more (NOAA normals) | 0 to 30 | 1 | United States only |
Cold and heat carry twice the weight of the other dimensions because heating and cooling demand act on a building every year, through its main mechanical systems.
Recorded flood history (Natural Resources Canada, historical flood event locations) is shown beside the index as context and is never scored: the publisher states the inventory is incomplete, so a missing record cannot honestly count in an area's favour.
Not in this version: wind, wildfire smoke and air quality, power reliability, elevation and topography, and building-age context. ICI does not yet have an approved source for the first four, and census data are excluded from every score.
How the dimensions combine
The index starts from the weighted average of the dimensions that have data. Then the most demanding dimension is checked: if it is below 50, the index is lowered by three quarters of the gap. So a severe condition cannot be hidden by several mild ones, and no single dimension can pull the whole index to zero on its own.
- Score each dimension with data on its fixed scale, rounded once to a whole number.
- Take the weighted average of those scores (cold and heat count twice).
- If the most demanding dimension is below 50, subtract three quarters of its gap below 50.
- Round the result once to a whole number. It cannot go below 0.
For example, an area with very mild winters but extreme summer heat (a heat score of 0) has a weighted average in the 60s. The heat shortfall lowers the index into the 20s, and the result names heat as the most demanding dimension. Each result shows the most demanding dimension and how much it lowered the index.
Two severe dimensions together can lower the index further, and in principle to 0. No area in the current data publishes 0 or comes within 10 points of it: the lowest values are 17 in Canada and 13 in the United States. Whether an index of 0 should be possible is one of the questions for independent review.
Worked examples
These are real results, produced by the same calculation the lookup uses. The table is generated from it, so the two cannot differ.
| Area | Dimensions with data | Weighted average | Most demanding | Lowered by | Index | Range if missing data were known |
|---|---|---|---|---|---|---|
| Phoenix, Arizona (85004) | Cold 95; Heat 0; Snowfall: no data; Freeze-thaw 100; Heavy precipitation 97 | 64.5 | Heat 0 | 37.5 | 27, shown as 27 | 18 to 32 |
| Minneapolis, Minnesota (55401) | Cold 57; Heat 84; Snowfall: no data; Freeze-thaw 67; Heavy precipitation 73 | 70.33 | Cold 57 | 0 | 70.33, shown as 70 | 23 to 75 |
| Miles City, Montana (59301) | Cold 58; Heat 84; Snowfall: no data; Freeze-thaw 36; Heavy precipitation 95 | 69.17 | Freeze-thaw 36 | 10.5 | 58.67, shown as 59 | 22 to 63 |
| Calgary, Alberta (T2P) | Cold 50; Heat 98; Snowfall 72; Freeze-thaw: no data; Heavy precipitation: no data | 73.6 | Cold 50 | 0 | 73.6, shown as 74 | 15 to 81 |
| Arviat, Nunavut (X0C) | Cold 0; Heat 100; Snowfall 77; Freeze-thaw: no data; Heavy precipitation: no data | 55.4 | Cold 0 | 37.5 | 17.9, shown as 18 | 2 to 31 |
When data is missing
A dimension without an approved value is shown as unavailable with its reason. It is never counted as zero, never counted in an area's favour, and never part of the average. Every result shows its data coverage as "x of 5 supported dimensions", and the range the index could fall in if the missing dimensions were known. An overall index is shown only when at least three dimensions, including cold and heat, have data.
Geography
You enter the first three characters of a Canadian postal code or a five-digit United States ZIP code. Each value comes from the nearest climate station that publishes it within 50 km of the postal area's reference point, and the result names the area, the station and the distance. Nothing is claimed at street, block or building level. Where a postal area covers separated communities, you choose the one closest to the building. Canadian and United States results draw on different national sources, so they are not compared with each other.
Versions and updates
Every result carries the method version, the date it was produced, the data period, its coverage, each component and its source. The method changes only through a new numbered version recorded on this page. When the national climate normals move to a new 30-year period, the update arrives as a new version, and earlier results keep their version.
Independent review
Version 1.0 is reproducible: every published value is recalculated independently and matches exactly. Reproducing a calculation is not the same as validating it, so the judgement settings are going to an independent building-science reviewer:
- the scale end points for each dimension;
- the weights (cold and heat 2, the others 1);
- the severity rule (a threshold of 50 and a rate of three quarters), including whether an index of 0 should be possible;
- whether two severe dimensions should count for more than one;
- the 50 km station distance;
- publishing Canadian and United States results, which use different dimensions, side by side.
If the review changes any setting, the result becomes a new numbered version and earlier results keep version 1.0. The status shown on every result changes only when the review is complete and accepted.
Known limitations
The scale end points, the weights and the severity rule are judgement settings awaiting expert review. A station can sit at a different elevation or exposure from parts of the area it represents. Freeze-thaw in the United States is counted from daily normal temperatures, which understates single-day crossings. Nothing here is a measurement at any building.