What does San Diego Precipitation predict for SPY?

Historically, San Diego Precipitation has pointed to a decline in SPY over the next year, hitting in that direction 30% of the time (n=6420). This is descriptive backtest data, not investment advice.

How often does San Diego Precipitation update?

San Diego Precipitation is recomputed daily as part of Standard Poorly's nightly data refresh; the latest reading is from 2026-06-01.

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PoorlyweatherSP-5251

San Diego Precipitation

Name: San Diego Precipitation — leading indicator vs SPY
Creator: Standard Poorly
License: https://standardpoorly.com/terms

Total daily precipitation (San Diego, mm).

Sectors:Regional Metros Weather & Climate

the verdict —

At the 252d horizon, this signal hits in the predicted direction 30% of fires. Mean SPY forward return when it lights: -5.73%. Status: OOS validated. n = 6420. Bearish on the underlying when fired.

— Current state —

Latest value · 2026-06-01

0.00

vs 60 days ago

↓ 100%

vs 7 days ago

↓ 100%

last 90 observations · 2026-03-04 → 2026-06-01

— The series — full history —

Daily readings, every reading we have. Pick a window with the time-period buttons; flip to candles via the global toggle in the masthead (or press C). Toggle the SPY overlay to see how this series and the S&P 500 have moved together.

San Diego Precipitation

0.0000

Hover for date + value · Toggle SPY to compare relative move

2025-09-23 → 2026-06-01  ·  252 bars

— What it has historically predicted —

On days when this signal fires (deviates 2+ standard deviations from its 30-day average, in either direction), SPY has historically averaged -5.7% over the next year, moving in the opposite direction 70% of the time.

↓53%

−0.02%

1 d

↓56%

−0.15%

1 wk

↓60%

−0.49%

1 mo

↓63%

−1.3%

3 mo

↓65%

−2.7%

6 mo

↓70%

−5.7%

1 yr

⎘

— Beyond SPY — how this signal performs across markets —

Same fire days, different forward returns. Each row asks: when this signal fires, what does that asset do? The big number is the average return; underneath is how often the asset moved the same direction as the signal (50% would be a coin flip).

target

1 d

1 wk

1 mo

3 mo

6 mo

1 yr

SPY

S&P 500 ETF

n=6,420

-0.02%

47% same direction

-0.15%

44% same direction

-0.49%

40% same direction

-1.3%

37% same direction

-2.7%

35% same direction

-5.7%

30% same direction

Gold

futures

n=6,246

-0.03%

48% same direction

-0.16%

46% same direction

-0.69%

45% same direction

-2.4%

39% same direction

-5.2%

34% same direction

-10.3%

31% same direction

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Regime-tuned params · AutoResearch v13Analyst · preview

Regime matters

This indicator's strongest predictive edge sits in High VIX (stress): tuned σ = 2, window = 180d, horizon = 126d, hit-rate deviation from chance = 50.0pp.

Regime	σ	Window	Horizon	Hit dev
● Low VIX (calm)	2.00	240d	252d	42.6pp
● Normal VIX	2.50	90d	252d	34.1pp
● High VIX (stress)	2.00	180d	126d	50.0pp

Hit-rate deviation = |hit% − 50%| at the row's tuned horizon. Big deviation = strong directional edge in that regime. Regimes split by daily VIX terciles (low / normal / high) over a 1-year rolling window. Analyst + Trader subscribers will be able to filter the home grid and the fire-history bar chart by regime.

shaded cell = each row's strongest horizon (green = bullish forward return, red = bearish)“same direction” means the asset moved the same way the signal moved — opposite of a coin flip.

Analyst · previewYou're seeing the public read on this signal. Analyst unlocks the full multi-year track record + bootstrap confidence intervals + an alert when this indicator fires. Trader adds the walk-forward backtest + intraday refresh + the API / MCP to pull this signal into Claude.Compare tiers →