Two uses, two different requirements. These sources serve two purposes: index design (calibrating trigger thresholds using long historical records) and trigger verification (confirming after an event whether a threshold was breached). For trigger verification, the data source must be specified in the policy as an independent, pre-agreed third-party reference confirm this with your legal and wording team before policy inception. Basis risk, the gap between what the index measures and what the insured actually experiences is the central challenge in parametric design; spatial resolution and station coverage limitations noted in each card are directly relevant to basis risk assessment.
NOAA HURDAT2 Best Track
NOAA National Hurricane Center
6-hourly maximum sustained wind speed and position data for every Atlantic and Eastern Pacific named storm since 1851. The standard trigger data source for Caribbean and US Gulf Coast parametric hurricane products. Historical record long enough for robust return period analysis at most trigger thresholds. Download in CSV or shapefile format.
IBTrACS : International Best Track Archive
NOAA NCEI
Global tropical cyclone archive covering all ocean basins, the source for parametric wind trigger design in Western Pacific typhoon, Indian Ocean cyclone, and Australian cyclone products. Use IBTrACS for any basin not covered by HURDAT2.
ERA5 : ECMWF Reanalysis v5
ECMWF / Copernicus Climate Data Store
Hourly atmospheric reanalysis from January 1940 to present on a ~31km global grid — covering rainfall, wind, temperature, pressure, humidity, and dozens of other variables. The standard dataset for designing rainfall-indexed parametric products globally. Used heavily in agricultural parametric design for India, Africa, and Southeast Asia. Access via the Copernicus Climate Data Store (CDS) with free registration; Python API (cdsapi) available for bulk download.
CHIRPS : Climate Hazards Group InfraRed Precipitation with Station Data
Climate Hazards Center, UC Santa Barbara
High-resolution (0.05°, ~5km) rainfall dataset from 1981 to present combining satellite infrared imagery with ground station observations. The preferred dataset for agricultural parametric products in developing markets Africa, Latin America, and South Asia.
GPM IMERG : Global Precipitation Measurement
NASA Earth Data
Near-real-time satellite-derived rainfall data globally updated every 30 minutes at 0.1° (~10km) resolution. Used for near-real-time trigger monitoring in parametric products where rapid post-event assessment is required. Final run (latency ~3.5 months) is more accurate than the Early run (latency ~4 hours) specify which run is used for trigger determination in the policy.
IMD Gridded Rainfall Data
India Meteorological Department
India-specific gridded daily rainfall data at 0.25° resolution from IMD ground station network. The standard reference dataset for Indian agricultural parametric products the PM Fasal Bima Yojana (PMFBY) crop insurance scheme uses IMD data as the trigger reference for rainfall deficit products.
ECMWF Seasonal Forecasts
ECMWF / Copernicus Climate Data Store
Seasonal probabilistic forecasts of rainfall, temperature, and other variables at lead times of up to 6 months. Used in parametric products with seasonal triggers El Niño-linked rainfall deficits in East Africa and Southeast Asia, Indian monsoon season rainfall, and Atlantic hurricane seasonal activity.
USGS ShakeMap
United States Geological Survey
Modelled peak ground acceleration (PGA), peak ground velocity (PGV), and Modified Mercalli Intensity (MMI) maps published within minutes of any significant earthquake globally. The standard free source for portfolio-level earthquake intensity triggers specifying "USGS ShakeMap PGA at location" as the trigger index is established practice.
USGS PAGER : Prompt Assessment of Global Earthquakes for Response
United States Geological Survey
Rapid assessment of the likely human and economic impacts of significant earthquakes published within 30 minutes of a major event. Used in parametric products triggered by estimated economic or humanitarian impact relevant for sovereign parametric disaster risk financing where payout is linked to estimated loss rather than ground motion measurement.
NOAA Tides and Currents
NOAA Center for Operational Oceanographic Products and Services
Real-time and historical tide gauge data at hundreds of US coastal stations water level, tidal predictions, and storm surge measurements. Used for parametric coastal flood products triggered by measured water level at a specified gauge station. Historical records at major stations extend back decades, providing robust return period analysis.
Copernicus Marine Service (CMEMS)
European Commission / Copernicus
Global ocean monitoring and forecasting sea surface temperature, significant wave height, sea level anomalies, and ocean currents. Used for marine parametric products triggered by sea surface temperature (relevant for coral reef insurance, aquaculture, fisheries) or significant wave height (relevant for offshore energy parametric products). Increasingly relevant as the blue economy parametric market develops.
ERA5 : 2m Air Temperature
ECMWF / Copernicus Climate Data Store
Hourly 2m air temperature from 1940 to present on a ~31km global grid the same ERA5 reanalysis used for rainfall triggers, covering temperature as a separate variable. Used for heat stress and cold snap parametric products energy sector demand-response parametric, livestock mortality parametric, and cold chain disruption products. The same spatial resolution caveats apply as for rainfall: suitable for area-based triggers, higher basis risk at individual asset level.
NOAA Climate Data Online (CDO)
NOAA National Centers for Environmental Information
The most comprehensive US weather station archive daily and sub-daily temperature, precipitation, wind, and humidity observations from thousands of stations, many with records extending over a century. The standard source for US station-based parametric trigger design where a specific named weather station is specified as the trigger reference in the policy. Free download in multiple formats.
NASA MODIS NDVI
NASA Earth Data
Normalised Difference Vegetation Index a satellite-derived measure of vegetation greenness and health, updated every 16 days at 250m–1km resolution. Used in parametric agricultural products triggered by vegetation condition rather than rainfall directly eliminating the basis risk from measuring rainfall as a proxy for crop health. More directly correlated with actual crop condition than rainfall indices, but requires careful calibration against historical yield data for each crop type and region.
Copernicus Global Land Service
European Commission / Copernicus
Global land surface monitoring products including NDVI, Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), soil moisture, and fire radiative power at 300m to 1km resolution, updated daily to bi-monthly depending on the product. Increasingly used in agricultural parametric design in Europe and globally as an alternative or complement to MODIS NDVI broader variable set allows more sophisticated multi-index parametric structures.
Free weather API with no API key required provides ERA5 reanalysis from 1940 to present and 30+ operational weather model forecasts. Request any combination of wind speed, rainfall, temperature, humidity, and other variables for any location globally in JSON format. The most accessible entry point for pulling historical trigger data programmatically a single API call returns decades of hourly data for a specified lat/lon coordinate. No registration, no rate limiting for reasonable usage.
NOAA GSOD : Global Surface Summary of Day
NOAA National Centers for Environmental Information
Daily weather observations temperature, precipitation, wind speed, visibility from weather stations globally, available in bulk download or via the NOAA API. Used for station-based parametric trigger design globally where a specific named station is the trigger reference. Longer historical records than satellite datasets for many locations some major stations have data from the 1930s onwards.