The Precipitations KPI measures the annual precipitation anomaly at a monitored site, expressed as a percentage deviation from the 1961--1990 WMO climatological baseline — the international standard reference period for precipitation normals. The KPI scalar value is computed from the mean precipitation of the last three years compared against this historical average.
A distinctive feature of this indicator is that it is inverted and symmetric: both drought conditions (deficit) and flooding conditions (surplus) are equally penalized. The gauge uses the absolute value of the anomaly, so a site receiving 30% less rain and a site receiving 30% more rain are scored identically. This reflects the ecological understanding that both extremes stress biodiversity and ecosystem function.
The KPI does not have a future projection mode on the gauge — it is a pure historical indicator. Future precipitation projections under SSP climate scenarios are visualized separately in the "Precipitation in recent years" line chart.
The quality classification follows five grades:
| Level | Anomaly (absolute %) | Ecological meaning |
|---|---|---|
| A (Excellent) | 0 -- 5.2 | Precipitation within historical norms |
| B (Good) | 5.2 -- 10.6 | Slight deviation; negligible water stress |
| C (Moderate) | 10.6 -- 16.5 | Moderate anomaly; possible seasonal water stress |
| D (Poor) | 16.5 -- 27.0 | Significant anomaly; drought or flooding risk |
| E (Critical) | > 27.0 | Severe anomaly; strong impact on ecosystems |
The precipitation anomaly is calculated by comparing recent rainfall against the long-term historical average:
where the numerator is the difference between the mean annual precipitation over the last three years and the 1961--1990 baseline mean, and the denominator is the baseline mean itself.
The gauge uses the absolute value of this anomaly for positioning and quality grading. Both deficit (negative) and surplus (positive) anomalies map to the same quality level.
Data are sourced from Open-Meteo Historical Weather (ERA5-Land reanalysis) at approximately 10 km spatial resolution, covering the period from 1940 to the present.
Gauge. A semicircular sector gauge showing the precipitation anomaly as a percentage, with three comparison delta rows below.
Purpose: Is this site receiving significantly more or less rain than its long-term historical average, and has this changed over the past decades?
Description: The gauge occupies the left half of the Microclimate section card, alongside the "Precipitation in recent years" line chart. The section header shows the title "Rain E1 - E3" with an ESRS badge "E1 - E3", a tooltip icon, and a download button. Below the header, a "Site score" label appears above the gauge arc. The semicircular arc spans from A (0%) at the right to E (100%) at the left — note that this gauge is inverted compared to most others, so the best quality (A) is on the right. The current precipitation anomaly value (e.g., "+48.7 %") is displayed in bold at the center. A benchmark dash ("-") appears above the value. Below the gauge, three delta rows show precipitation change comparisons labeled "Change in the last 3 years", "Change in the last 10 years", and "Change in the last 50 years", each with a colored percentage badge indicating the magnitude.
48.7%Precipitation Anomaly
How it's calculated: The displayed percentage is the absolute value of the precipitation anomaly formula above. The gauge arc color follows the quality scale below. The three delta rows show the difference in 3-year running means at 3, 10, and 50-year intervals to reveal precipitation trends over time.
Note: This indicator is inverted — higher anomaly values (either drought or surplus) indicate worse ecological conditions. The A grade corresponds to precipitation closest to the historical norm; E corresponds to the most extreme deviation.
Legend:
| Level | Anomaly Range | Color | Meaning |
|---|---|---|---|
| A (Excellent) | 0 -- 5.2% | ■ #00A67A | Precipitation within historical norms |
| B (Good) | 5.2 -- 10.6% | ■ #00DF80 | Slight deviation; negligible water stress |
| C (Moderate) | 10.6 -- 16.5% | ■ #FFD21E | Moderate anomaly; possible seasonal water stress |
| D (Poor) | 16.5 -- 27.0% | ■ #FF8B16 | Significant anomaly; drought or flooding risk |
| E (Critical) | > 27.0% | ■ #FF367F | Severe anomaly; strong impact on ecosystems |
Interpretation example:
If the gauge shows +48.7%, it means the site has received about 49% more (or less) rain than its 1961--1990 historical average over the last three years. This falls in the E (Critical) range, indicating a severe precipitation anomaly that poses significant risks to soil moisture balance, species hydration needs, and flood or drought management.
Line Chart. A scrollable area/line chart showing annual precipitation totals from 1940 to the present, with an optional future projection mode via a Past/Future toggle.
Purpose: How much rain has this site received each year historically, and what do future climate projections show under different emission scenarios?
Description: The chart occupies the right half of the Microclimate section card, alongside the precipitation gauge. The header shows the title "Precipitation in recent years", a tooltip icon, and a download button. A Past/Future toggle appears below the header; when "Future" is selected, a dropdown appears to choose the SSP scenario (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5). The chart area displays one data point per year as an area chart with circle markers. In historical mode, points are colored by the annual precipitation level relative to the quality ranges. In future mode, a dashed semi-transparent blue line is shown with model uncertainty. The chart is scrollable horizontally to navigate the full 1940-to-present range.
How it's calculated: Each data point is the annual precipitation total (in cm) for that year, derived from ERA5-Land daily precipitation values aggregated annually. Values are stored internally in tenths of mm and displayed as cm (divided by 10). For future projections, the CMIP6 multi-model ensemble median is shown per SSP scenario, with standard deviation shown in the tooltip. The tooltip displays: year, precipitation total (cm), and delta vs. the 1961--1990 baseline.
Legend: Data point colors follow a quality scale based on absolute annual precipitation:
| Level | Range (cm) | Color | Meaning |
|---|---|---|---|
| A | 160 -- 200 cm | ■ #00A67A | Very high annual precipitation |
| B | 120 -- 160 cm | ■ #00DF80 | High precipitation |
| C | 80 -- 120 cm | ■ #FFD21E | Normal precipitation range |
| D | 60 -- 80 cm | ■ #FF8B16 | Below-normal precipitation |
| E | 0 -- 60 cm | ■ #FF367F | Very low annual precipitation |
Future mode fill: semi-transparent blue with dashed line.
Interpretation example:
If bars from 1990 to 2010 are mostly in the C (yellow, 80--120 cm) range and bars from 2015 onward drop to D (orange, 60--80 cm), the site is experiencing a long-term drying trend. Under SSP5-8.5, if future projections show values below 60 cm by 2040, the site risks entering E (Critical) conditions with severe ecological implications for vegetation, soil moisture, and biodiversity.
Line Chart. A multi-variable daily time series chart with 23 selectable meteorological variables, including precipitation-related ones.
Purpose: What are the detailed daily patterns for precipitation variables over the past 5 years?
Description: When the user selects the precipitation or rain variable in the dropdown selector, the chart shows a single mean line (daily total precipitation in mm). Per-point coloring is applied based on severity ranges derived from the 1961--1990 reference percentiles. Min/Mean/Max statistics are shown above the chart only for variables that provide all three (precipitation variables show mean only).
How it's calculated: Daily precipitation values come from ERA5-Land reanalysis. Severity coloring is computed by comparing each daily value against the 1961--1990 percentile thresholds.
Interpretation example:
If the precipitation variable shows persistently low daily values (red coloring) throughout summer 2023, this signals an unusual dry spell relative to the historical baseline for that season — a pattern consistent with the anomaly flagged by the gauge indicator.
Sites Progress Column. A column of the multi-site comparison table in the Risks & Opportunities section, showing annual precipitation in mm for each site.
Purpose: Enables rapid comparison of the precipitation level across multiple portfolio sites to identify drier or wetter sites.
Description: Each row in the table corresponds to one site. The column header "Rain (mm)" shows the annual total precipitation in millimeters. This is the raw mm value of annual precipitation, not the anomaly percentage shown in the gauge.
How it's calculated: The annual precipitation total for the site's coordinates, sourced from ERA5-Land reanalysis.
Interpretation example:
If a site shows "650 mm" in this column while the historical average is 900 mm, it is receiving about 28% less rain than normal — which would map to a D/E anomaly on the precipitation gauge.
Data Table. A tabbed risk analysis panel within the Climate risk category, one of eight tab options alongside Heat waves, Cold waves, Fires, etc.
Purpose: Provides a forward-looking risk assessment for precipitation-related climate hazards at the site.
Description: The "Precipitation" tab appears in the "Key risk aspects" section under Climate risks. When active, it shows the shared risk layout (spider chart, result card with probability and intensity scores, and a detail modal for further information). The panel is hidden by default; it becomes active when the user clicks the tab.
How it's calculated: Risk scores are computed from CMIP6 climate projections for precipitation changes, following the shared risk analysis methodology.
Interpretation example:
If a site shows "High" precipitation risk, it means climate models project significant departures from historical precipitation patterns under mid-to-high emission scenarios, increasing the probability of seasonal flooding or prolonged drought.
Data Table. A tabbed risk analysis panel for changes in the seasonal distribution, intensity, and frequency of precipitation.
Purpose: Distinguishes structural shifts in rainfall patterns (when rain falls, not just how much) from the overall anomaly measured by the gauge.
Description: The "Precipitation pattern change" tab appears alongside "Precipitation" in the Climate risk section. It follows the same shared risk layout. Risk level categories: Very Low, Low, Medium, High, Very High. SSP scenarios SSP1-2.6 (green), SSP3-7.0 (yellow), SSP5-8.5 (red) are shown as separate lines in the projection chart.
How it's calculated: Based on seasonal precipitation ratio changes, wet/dry day frequency shifts, and intensity distribution changes from Copernicus CDS CMIP6 data at approximately 100 km resolution.
Legend:
| Level | Color | Meaning |
|---|---|---|
| Very Low / Low | ■ #34d399 | Minimal pattern shift expected |
| Medium | ■ #fbbf24 | Moderate seasonal redistribution |
| High | ■ #f97316 | Significant pattern change; adaptation needed |
| Very High | ■ #ef4444 | Major structural shift in rainfall regime |
Interpretation example:
A site showing winter precipitation increasing 30% while summer drops 40% under SSP5-8.5 by 2070 would score "High" or "Very High" for this risk — even if the annual total remains similar, the seasonal shift stresses summer-adapted vegetation and increases winter flood risk.
| Source | Provider | Coverage | Resolution | Period |
|---|---|---|---|---|
| Open-Meteo Historical Weather (ERA5-Land) | Open-Meteo | Global | ~10 km | 1940 -- present |
| Climate Data Store CMIP6 | Copernicus / ECMWF | Global | Model-dependent | Projections to 2100 (line chart only) |
Daily precipitation values (in mm) are retrieved from the Open-Meteo ERA5-Land API for the site coordinates. These are aggregated to monthly totals and then annual totals.
The KPI scalar is derived by computing the mean annual precipitation over the last three years, subtracting the 1961--1990 baseline mean, dividing by the baseline mean, and multiplying by 100. The gauge uses the absolute value of this result for positioning and quality grading.
The gauge component also computes three delta rows comparing the 3-year running mean against earlier reference periods:
For future projections shown in the line chart, CMIP6 multi-model ensemble data uses multiplicative bias correction (unlike the additive correction applied to temperature projections), because precipitation anomalies scale proportionally.