Precipitation of driest month — 1981-2010 (CHELSA)
This layer maps how much rainfall falls in the driest month of a typical year, averaged over the 1981-2010 reference period.
Category: Physical risks · Mitigating services · Climate Chronic Risks · 1981-2010 Coverage: Global Format: Raster grid (~2 km) Used in risk analysis: No (contextual layer; not used in materiality scoring)
What it shows
This layer maps how much rainfall falls in the driest month of a typical year, averaged over the 1981-2010 reference period. It is a bioclimatic indicator describing the depth of the seasonal dry period, which shapes water availability, vegetation stress and the suitability of land for different crops and ecosystems.
How it is built
The layer comes from CHELSA-CMIP6 v2.1, a high-resolution global climatology developed by Karger and colleagues. The measured variable is the precipitation total of the driest calendar month, derived from the 1981-2010 baseline climate record. It is presented as a reference climatology on a fine global grid of roughly 2 km, making it considerably more detailed than typical coarse climate datasets.
How to read it
Higher values indicate wetter conditions even in the driest month — a milder dry season; lower values indicate more pronounced seasonal drought, with the driest month receiving very little rain. As a baseline layer it describes recent historical climate and is best read alongside the matching future-projection variant.
Source
CHELSA-CMIP6 v2.1 (Karger et al.), 1981-2010 reference climatology; open licence.
Comparison with the WWF Risk Filter Suite
The WWF Risk Filter Suite does not publish standalone bioclimatic precipitation variables of this kind. This baseline CHELSA layer is a climate-descriptor extension rather than a WWF risk indicator, so it has no direct equivalent in the WWF methodology.
Legend
Symbolised field: Precipitation of driest month
Generated from darwin/layers/layer-chelsa-precip_driestmonth-historical.toml and risk_indicator_pairs.toml (develop).