Household Strain Index

Petrol and diesel each score 0 at their 2019 UK average (125.0p and 131.7p a litre) and 100 at their July 2022 weekly highs (191.6p and 199.2p, week of 4 July 2022), with scores capped at 100; the part is the mean of the two.

Reference points: DESNZ weekly road fuel prices, 2018 to 2026. Daily readings: Fuel Finder (all reporting forecourts) from 24 September 2026, the CMA retailer price files before that. Our daily averages come from a different sample from DESNZ's weekly survey; on 21 September 2026 the retailer files ran about 1.5p a litre above it for diesel.

Unplanned power cuts in progress at the day's highest reading, per network reporting, on a log scale: 25 per network (a typical day in our first two months) scores 0 and 250 per network scores 100. Planned engineering work is left out.

Live outage feeds of the distribution networks that publish them (four of Britain's six in September 2026, all six since 14 October 2026). Counts cuts, not homes. Two readings a day, so a short spike between them is missed. A network whose feed fails that day is left out of the average, and a day with fewer than two networks reporting has no reading. Electricity North West and SP Energy Networks are read from 14 October 2026, so readings before then cover four networks.

The highest Met Office warning in force that day: none 0, yellow 40, amber 75, red 100, plus 4 for each further warning, up to 20 more.

Met Office National Severe Weather Warning Service.

Flood warnings in force at the day's highest reading, with each severe warning counted three times, on a log scale: 2 or fewer scores 0 and 150 scores 100.

Environment Agency real-time flood-monitoring API (England). England only. Flood alerts, the lower level, are not counted.

Flu and COVID-19 test positivity (the share of tests that come back positive) each score 0 at their typical level, the median of the 2025/26 season (1.5% for flu, 2.4% for COVID-19), and 100 at their highest since July 2022, the first full season after free COVID-19 testing ended (flu 32.6%, week of 19 December 2022; COVID-19 17.7%, 5 October 2023). The part is whichever of the two scores higher.

UKHSA data dashboard: weekly flu test positivity and the 7-day average of COVID-19 test positivity, England. England only. UKHSA publishes each week about ten days after it ends, so this part runs behind the others, and positivity depends on who is being tested.

The share of the water companies we check that have a hosepipe ban in force: none scores 0, all of them 100.

Environment Agency weekly drought report, and the Welsh companies' own announcements. England and Wales; a weekly source.

The highest UKHSA heat-health or cold-health alert in any English region: green 0, yellow 40, amber 75, red 100.

UKHSA and Met Office Weather-Health Alerting System. England only. Outside the alert seasons the level sits at green, so an older reading still stands.