Sources & Methodology

Every tool on The Tea Leaves pulls from public data. This page lists what each one reads, where to verify it, and any methodology notes worth knowing.

Approach

Data is fetched at page-load time directly from public APIs (Open-Meteo, USGS, NASA FIRMS, CDC, EIA, and others). Nothing is stored on a server. Static data — BLS price series, seasonal produce windows — is refreshed via scheduled builds on GitHub Actions and committed to the repository as JSON files.

When a tool shows a calculated metric (wet-bulb temperature, AQI band, economy index), the calculation happens in your browser. The source values are always traceable back to the underlying agency.

None of this is financial, medical, or safety-critical advice.

Wet Bulb Monitor

→ wetbulb

Current and forecast wet-bulb temperature — the threshold above which sweat can no longer cool the human body.

Open-Meteo Temperature, humidity, wind — current and 72-hour hourly forecast. Free, attribution-based weather API.
Open-Meteo Geocoding Reverse geocoding for the user's location label.
Stull (2011) Wet-bulb temperature approximation formula from relative humidity and air temperature at sea-level pressure. Stull, R. J. Applied Meteorology and Climatology, 50(11), 2267–2269. Valid for RH 5–99% and temperatures −20° to 50°C.

Air Quality Monitor

→ airquality

US AQI, PM2.5, ozone, NO₂ — local conditions, forecast, and global monitor. Includes active wildfire hotspots from NASA satellite detection.

Open-Meteo Air Quality CAMS (Copernicus Atmosphere Monitoring Service) — global AQI, particulate matter, and pollutant forecasts.
NASA FIRMS VIIRS satellite fire-detection hotspots — global, updated multiple times daily. Fire Information for Resource Management System.

Hazards & Climate

→ hazards

Active weather alerts, tropical systems, earthquakes, droughts, precipitation and temperature anomalies, ENSO state, and long-term climate indicators.

NOAA NWS API Active watches, warnings, and advisories across the United States.
NOAA NHC National Hurricane Center — active tropical cyclones, storm surge, and forecast cones.
USGS Earthquake Real-time earthquake feed — magnitude 2.5+ worldwide over the last 24 hours.
U.S. Drought Monitor Weekly drought classifications by county, produced jointly by NOAA, USDA, and the National Drought Mitigation Center.
NOAA CPC ENSO Oceanic Niño Index — El Niño / La Niña state from Climate Prediction Center.
NOAA GML Mauna Loa Atmospheric CO₂ concentration — the canonical Keeling Curve. Weekly Mauna Loa values; preindustrial baseline 280 ppm.
NOAA GML Methane Globally-averaged atmospheric methane (CH₄) — monthly mean from the marine boundary layer reference network. Preindustrial baseline ≈722 ppb.
NSIDC National Snow and Ice Data Center — daily Arctic and Antarctic sea-ice extent.
NASA GISTEMP Goddard Institute global surface temperature anomaly — one of the main long-term warming records.
NOAAGlobalTemp NOAA's parallel monthly global temperature anomaly dataset, used alongside GISTEMP for cross-check.
NCEI Ocean Heat Content Global ocean heat content 0–2000m — yearly time series from Argo profiling floats. The ocean absorbs roughly 90% of excess heat trapped by greenhouse gases, so OHC is the most direct measure of accumulated planetary energy imbalance.
Open-Meteo Climate 30-day precipitation and temperature totals compared against long-term local normals.

Outbreak Monitor

→ outbreak

Wastewater-based viral surveillance for COVID-19, Influenza, and RSV by US state. Wastewater lags clinical cases by less than symptoms — and doesn't depend on testing behavior.

CDC NWSS National Wastewater Surveillance System — viral activity levels from wastewater treatment facilities. Updated Fridays.

Everyday Economy Index

→ economy

An index that translates commodity prices, interest rates, and labor data into an approximate dollar-per-month impact versus a January 2025 baseline.

FRED Federal Reserve Economic Data — interest rates, employment, CPI, wage series.
Yahoo Finance Commodity and equity prices — crude oil, natural gas, wheat, corn, gasoline futures.
BLS Consumer Expenditure Survey Household spending weights — used to translate category movements into dollar impact. Baseline: January 2025. Monthly household spend used for translation: configurable in the page.

Upstream Pressure

→ upstream

Leading indicators that drive prices in the other tools — commodities, shipping, interest rates, labor. Changes here usually show up downstream in 1–6 months.

FRED Interest rates, employment, labor, CPI components.
Yahoo Finance Commodity futures and spot prices.
US EIA Energy Information Administration — crude, natural gas, refined products.

Grocery Price Radar

→ grocery

Individual grocery item prices with buy signals, seasonal windows, and trend direction.

BLS Average Prices Bureau of Labor Statistics Average Price series — monthly, national, not seasonally adjusted. Buy signals combine price level (vs. 12-month average) with momentum (90-day vs. 180-day moving average crossover).
USDA Seasonal Produce Guide Peak local season windows, split by northern/southern US regions.
Google News RSS News headlines relevant to individual commodities or categories.

Energy Cost Tracker

→ energy

Household energy costs — gasoline, electricity, natural gas, propane, diesel, heating oil — at state or PADD sub-region level.

EIA API Energy Information Administration retail price series, by state where available and by PADD sub-region for gasoline.

Grid Stress Monitor

→ grid

Real-time electricity demand versus capacity across the 7 major US grid operators. Requires a free EIA API key.

EIA Form 930 Hourly electric grid monitor — demand, forecast, and fuel mix per balancing authority. Updated hourly with 1–2 hour typical lag.
EIA API registration Free developer account for API access. Key is stored locally in your browser — never sent to any third party.

Macro Mood

→ macromood

Soft-data dashboard: how households, consumers, and businesses feel about the economy. Six FRED indicators, sign-corrected and z-scored against 10 years of history, weighted into a single 0–100 mood score and three tier trends. Tier weights: Households 50% (sentiment, saving rate, delinquency) · Behavior 30% (retail sales, jobless claims) · Business 20% (business confidence). Score = 50 + 20 × weighted z, clamped to 0–100.

UMCSENT University of Michigan Consumer Sentiment Index — monthly survey of household economic outlook. Published since 1952.
PSAVERT Personal Saving Rate — monthly, BEA. Share of disposable income saved by households.
DRCCLACBS Credit Card Delinquency Rate — quarterly, FRB. Share of credit card balances 30+ days past due. Inverted in the score (high = stress).
RRSFS Real Retail and Food Services Sales — monthly, Census. Inflation-adjusted spending — what people are actually buying, not just saying they will.
IC4WSA Initial Jobless Claims, 4-week moving average — weekly, DOL. The fastest-cadence labor signal on the page. Inverted in the score.
BSCICP03USM665S OECD Business Confidence Index for the US — monthly. Survey-based read on business expectations and outlook.

Affordability

→ affordability

Tracks essentials' share of disposable personal income over time. The hero is a 15-year monthly chart of (housing + food + energy + healthcare + transportation) ÷ disposable income. Tile percentiles are computed against the metric's own 10-year history. Each tile shows where its metric currently sits within its own 10-year distribution. High percentile on cost/stress tiles = more squeeze; high percentile on income tiles = healthier (the dial color band is inverted accordingly).

A067RC1 Disposable Personal Income — BEA, monthly. The denominator for every "share of income" calculation on the page.
DHUTRC1M027SBEA Personal Consumption Expenditures: Housing & utilities — BEA, monthly. The largest single line item for most households.
DFXARC1M027SBEA PCE: Food at home — BEA, monthly. Restaurants/food-services excluded as partly discretionary.
DNRGRC1M027SBEA PCE: Energy goods (motor fuel + household fuel) — BEA, monthly.
DHLCRC1M027SBEA PCE: Healthcare services — BEA, monthly.
DTRSRC1M027SBEA PCE: Transportation services — BEA, monthly. Used in the hero composite (not shown as a standalone tile).
CES0500000003 Average hourly earnings, all employees, private — BLS, monthly. Deflated by CPI for the Real Wages tile.
CPIAUCSL Consumer Price Index — BLS, monthly. Used as the wage deflator.
A229RX0 Real Disposable Personal Income per capita — BEA, monthly. Powers the Real Disposable Income tile and the hero context line.
TDSP Household Debt Service Payments as % of disposable income — Federal Reserve Board, quarterly.
PSAVERT Personal Saving Rate — BEA, monthly. Also appears on Macro Mood as a behavioral signal; here it's framed as household financial cushion.

Corrections & updates

If you find a broken link, outdated methodology, or a source that's been deprecated, open an issue on GitHub. This page is maintained manually and will drift over time.