Drought

About this module

Two products are shown. Rainfall compares the last three months with the same months in 1991–2020. Soil moisture compares the moisture in the top metre of soil with the same month in other years since 2015, and can be viewed every five days.

Rain and soil Experimental shows where rainfall and soil moisture disagree, and where both are low. The 3-month rainfall total is paired with that month's soil moisture, both are compared with the same years (2015 onwards) to find the gap, and a district is flagged only when its gap differs from the national pattern. "Dry on both" uses the same rules as the Rainfall and Soil tabs. April and May are not rated, because at the start of the rains the soil lags the rain. SMAP soil moisture is a model driven partly by its own rainfall estimate, so a gap can mean two rainfall estimates differ. A flag is a lead to investigate, not evidence of drought.

Rainy season Experimental shows when the main rains started this year in each district and whether that is earlier or later than usual. It has been checked against 14 rain gauges and typically differs from them by about three weeks, so treat the dates as satellite estimates and the colours as a rough guide. It is not planting advice.

Dry spells Experimental shows the longest run of days with under 1 mm of rain in each district during the main rainy season, compared with the same dates in 1991–2020. The period starts on the usual start of the rains and lasts 90 days. The lengths have not yet been checked against rain gauges, and because rain is averaged over a district, one farm can have a longer dry spell than the map shows. It is not a forecast and not crop advice.

Rainfall and soil moisture do not always agree. Soil moisture responds within days, while the three-month rainfall total changes slowly. Read the methods.