How each data panel works and where the numbers come from
Weather Workbench aggregates publicly available weather and energy data into one place for U.S. power market professionals. This page documents every data source, its update cadence, and any relevant calculation details. No proprietary data, paid API keys, or real-time meter reads are used — everything here is sourced from federal agencies and publicly accessible services.
→ See the Glossary for plain-language definitions of HDD, CDD, ISO/RTO, GFS, ECMWF, CPC outlooks, and other terms used throughout this site.
Gridpoint forecast data retrieved directly from the National Weather Service (NWS) API. Each city is mapped to an NWS forecast office and grid point. The API returns up to 15 days of hourly or 12-hour forecasts which are converted to daily high/low temperatures and probability of precipitation (PoP).
Temperature departure colors (red = above normal, blue = below normal) compare the forecast daily average against the corresponding 1991–2020 climatological normal for that location and date.
Heating Degree Days (HDD) and Cooling Degree Days (CDD) are computed from NWS gridpoint forecast data using a base temperature of 65°F — the industry standard for U.S. natural gas and power demand modeling.
A positive HDD departure means colder-than-normal temperatures (more heating demand). A positive CDD departure means hotter-than-normal (more cooling demand). These metrics are widely used by natural gas traders, utility planners, and weather-sensitive energy desks.
Active weather warnings, watches, and advisories issued by local NWS forecast offices within or overlapping each ISO footprint. Fetched from the NWS Alerts API filtered by geographic area.
Alert severity follows NWS classifications: Extreme, Severe, Moderate, Minor. Only alerts whose geographic areas intersect the ISO region are shown. Some alerts issued by state emergency agencies may not appear if they are not in the NWS alert feed.
Probabilistic temperature and precipitation outlooks issued daily by the NOAA Climate Prediction Center (CPC). These outlooks express the probability of above-normal, near-normal, or below-normal temperature and precipitation relative to the 1991–2020 base period.
These maps are most useful for identifying broad temperature and precipitation trends that drive energy demand at weekly timescales. CPC outlooks are not a single-point forecast — they show the likelihood of conditions being above, near, or below normal based on model agreement and large-scale climate patterns.
Wind speed and sky cover forecasts are extracted from the same NWS gridpoint data used for temperature forecasts. These are city-level proxy values — they reflect conditions at a few representative points within the ISO, not actual turbine or panel output.
Wind and solar tiers (Low / Moderate / High / Very High for wind; Excellent / Good / Reduced / Poor for solar) are heuristic classifications based on observed thresholds. They are indicative only and do not incorporate plant-level data, curtailment, or transmission constraints.
Weekly drought condition maps produced jointly by the National Drought Mitigation Center (NDMC), NOAA, and USDA. Drought affects hydroelectric generation, cooling water availability for thermal plants, and agricultural energy demand.
All-time peak electricity demand records for each ISO region, sourced from publicly available data published by individual ISOs and the U.S. Energy Information Administration (EIA). These are static historical figures and are not updated in real time.
Each data panel on the ISO detail page displays an "Updated X ago" indicator showing when the data was last fetched by this application. Browser-side caching means data may be served from memory between refreshes. Server-side cache times vary by data type:
Weather Workbench is a research and situational awareness tool, not a trading system or official forecast product. It does not provide real-time price data, actual generation meter reads, ISO dispatch signals, or licensed forecast products. Always verify critical data against primary sources before making operational or financial decisions.
We use cookies for analytics and to show ads from Google. You can accept all cookies or reject non-essential ones. See our Privacy Policy for details.