# How to read the US Drought Monitor > The US Drought Monitor rates drought on a five-step scale from D0, abnormally dry, to D4, exceptional drought, and publishes a new map every Thursday. It is a blend of many indicators and expert judgment, not a single formula, and it is not a reservoir or groundwater gauge. _Updated Jul 9, 2026._ The US Drought Monitor is a weekly map that grades drought from D0 to D4. D0 is abnormally dry, which is a watch category and not yet drought. D1 is moderate, D2 severe, D3 extreme and D4 is exceptional, the worst rating. A new map comes out every Thursday morning, produced jointly by the National Drought Mitigation Center, the USDA and NOAA. ## What the categories actually mean The scale is cumulative in how it is usually reported. When this site says a state is a certain percent in drought, that means the share of its area at D1 or worse, so D0 alone does not count as being in drought. The categories bundle together what conditions feel like on the ground: D1 brings some water shortage and voluntary restrictions, D3 and D4 bring widespread crop and pasture loss and emergency water measures. ## The Thursday release and its lag The map is released Thursday but the data cut off the previous Tuesday, so it always trails the weather by a few days. A big storm that lands Wednesday shows up in next week's map, not this one. That lag matters when conditions are moving fast. The Monitor is a considered weekly read, not a live sensor. ## It is judgment, not a single formula The Monitor is not the output of one equation. Authors weigh many inputs, precipitation, streamflow, soil moisture, snowpack and reservoir data, and then apply expert judgment, rotating the authorship each week. That is a strength, because no single index captures drought, and a limitation, because there is a human read in the loop. ## What it triggers, and what it does not measure The map is not just information. Drought categories feed real programs: USDA disaster designations, Farm Service Agency emergency loan eligibility and some insurance and relief provisions are tied to Monitor thresholds. Check the current program rules with the agency, because the specific triggers change. Just as important is what the Monitor does not do. It is not a groundwater gauge and not a reservoir gauge. A basin can show low drought on the map while its reservoirs are still drawn down from prior years, so read it alongside the storage pages, not instead of them. ## Worked example: reading one state's recent weeks [Table: California drought](https://the-waterline.com/drought/california) ([data](https://the-waterline.com/drought/california.md)) The table above shows California's drought coverage now against a week ago, a month ago, a year ago and the five-year median for this date, in percentage points. Read the week-over-week line for direction, the year-over-year line for how this season compares, and the five-year line for whether the state sits above or below its own normal. A state can be heavily in drought yet still be below its five-year normal, which is why we report the change in points rather than a single scary headline number. ## Related data + guides - [Drought tracker](https://the-waterline.com/drought) - [California drought](https://the-waterline.com/drought/california) - [What is a water curtailment?](https://the-waterline.com/guides/what-is-a-water-curtailment) ## Common questions ### What is the difference between D0 and D1 drought? D0 is abnormally dry, a watch category that flags dryness before it becomes drought. D1 is moderate drought, the first step that actually counts as drought. When coverage is reported as a percent in drought, it usually means D1 or worse, so D0 area is excluded. ### How often is the US Drought Monitor updated? Once a week. A new map is released every Thursday morning, using data through the previous Tuesday, so it lags fast-moving weather by a few days. ### Is the Drought Monitor a forecast? No. It describes current and recent conditions based on observed data and expert judgment. It does not predict future drought. Separate seasonal outlooks handle forecasting. ### Does the Drought Monitor measure reservoirs or groundwater? Not directly. It considers many indicators but it is not a storage gauge. A region can read low on the map while its reservoirs are still low from earlier dry years, so pair it with the reservoir and streamflow data. --- Canonical URL: https://the-waterline.com/guides/how-to-read-the-drought-monitor