The physics of Chico
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- #72 of 482 — Chico among California's cities. Chico's rank among California's 482 incorporated cities and towns — the rank-size line through the hundred largest (ζ = 0.70, flatter than Zipf's 1, so the big cities run closer in size than the rule expects) predicts 98,438 people at that rank; Chico has 102,911, 5 % over the line
- 0.22 — The shape of the streets. grid order of Chico's streets as a whole, where 1 is a perfect grid and 0 is every direction alike — three grids on three bearings cancel each other: Bidwell's 1860 plat (φ 0.93, turned 40° off the compass to run with Big Chico Creek), the Avenues north of the creek (φ 0.80, turned 31° the other way) and the postwar town around them (φ 0.21, laid north–south)
- every 4 years — The ground, shaking. a magnitude-5 earthquake within 150 km of Chico — 13 since 1970 in the USGS catalogue, and the Gutenberg–Richter law fitted to the 4,293 events outside the Geysers' induced swarm (b = 1.12) puts a magnitude 6 at about one every 93 years; the last was 2026's M5.6 near Redwood Valley; the closest big one, the 1975 Oroville M5.7, 41 km away, is the textbook case of a reservoir setting off a fault
- 35 → 18 days — Heat, frost and rain since 1906. 100-degree days a year at the Chico University Farm station, 1911–1940 against 1971–2000, the last thirty years it reported whole — a fall the climate literature lays to the irrigation of the valley, which cools summer afternoons; at Orland, 32 km west on the same floor with a record whole to this year, the count has turned back up, 18 a year in 1991–2020 to 22 in 2001–2024, and a mid-century rise of +3.1 °F (a projection: RCP 4.5 ensemble mean for 2040–2069, Cal-Adapt) shifted onto those days would make it about 35
- −1.1 ft a year — The water table. the water table under Chico, by the trend of the yearly median depth to water across a fixed panel of 40 monitored wells in the Vina subbasin, 2005–2025 — 16 ft deeper than in 2005 and, at this rate, 19 ft deeper again by 2042, the statute's horizon (the current trend, 0.36–1.82 ft a year by bootstrap, carried forward from the latest median: a projection, not a forecast)
- 106 gal/day — Water, by the person. residential water use per person in Chico, August 2025 to July 2026 (the latest twelve months the state board has posted) — 1.2× the state average; September uses 3.0× what March does, the 10th-largest summer swing among the 188 suppliers serving 50,000 or more
- −4,519 jobs — The economy's metabolism. Butte County private employment against the comparator counties' path in 2020-Q1, the widest point of the Camp Fire deviation and the last quarter before the pandemic — it was still widening, so no relaxation time could be measured (placebo rank 1 of 11)
- +9.2 % — Rent and the housing stock. excess rent in Chico 12 months after the Camp Fire (November 2019) — Chico's ZORI indexed to October 2018 against a synthetic Chico weighted from 25 California cities chosen by rule (Livermore (31 %), Chino (25 %), Temecula (20 %), Brentwood (11 %), San Ramon (9 %), Merced (2 %) and Menifee (1 %)); the excess peaked at +10.5 % in July 2019 and relaxed with τ no longer than the index's smoothing window (three months) toward a plateau of +8.2 %; among 26 cities treated in turn Chico's peak ranks 1 (p = 0.04); in August 2026 Chico sat 2.1 % below the control
- $110.9 million — Money in and money out. federal awards with a place of performance in Chico in fiscal 2025 (USAspending obligations; 13.8 % grants, the Department of Education the largest awarding agency) — $1,077 per resident
- D+48.8 to D+10.3 — The electorate by district. the two-party presidential vote across Chico's seven council districts in November 2024, District 5 to District 1; the 3 districts on the November 2026 ballot voted District 2 D+16.9, District 4 D+39.7 and District 6 D+16.6 for president
- 61% — The council's record. of the 2,742 regular City Council motions recorded in the minutes since 2008 (consent calendars apart) had no vote against; on the 90 contested votes of the sitting council the same 3 members were the minority 34% of the time
- τ = 10.9 days — The pulse: hours to days. Big Chico Creek's recession constant after a peak, the median over 30 peaks of the daily record (days 3–20, ln Q against time); 1 storm in the last 400 days had a resolved peak at the gauge, too few yet for a lag