Live market data
CAISO solar forecast
CAISO's real-time-dispatch solar forecast against actual output — the fleet that defines the shape of the entire California market, updated continuously.
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CAISO's real-time-dispatch solar forecast against actual output — the fleet that defines the shape of the entire California market, updated continuously.
How much solar power will California get?
CAISO solar output peaks at 19,662 MW on Sat, 12 PM, against a low of 0 MW — a swing of 19,662 MW across the window. Solar forecast is the heaviest area at 19,662 MW.
Every line above, and who produced it.
What settled — the realized values every forecast here is scored against.
The grid operator's own published forecast for these hours. Source: CAISO.
Each day of the window on its own.
Every hour of the window, shaded by load.
| 0 | 6 | 12 | 18 | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thu, 8/27 |
| Series | Peak (MW) | Peak hour | Low (MW) | Average (MW) |
|---|---|---|---|---|
| Solar forecast | 19,662 | Sat, 12 PM | 0 | 6,869 |
| Solar settled (recent) | 12,199 | Thu, 11 AM | -62 | 4,271 |
| Forecast | Avg miss (MW) | Avg miss % | Bias | Hours |
|---|---|---|---|---|
| CAISO solar forecast | 50 | 100.0% | +50 | 2 |
The latest published vintage of each forecast, against what settled. Smaller is better on every column. Bias is signed: positive means the forecast ran high.
| Forecast | Produced by | Method | Horizon |
|---|---|---|---|
| Solar forecast | CAISO | CAISO renewables forecast (RTD) and actual generation, system solar | About 2 days ahead, hourly |
CAISO publishes a point forecast with no confidence interval. Marine-layer and monsoon cloud cover are the dominant error sources; clear-sky days verify almost exactly.
CAISO's real-time dispatch process forecasts utility-scale solar output over the next hours at five-minute resolution. This page plots the current forecast against actual production. It is the operational near-term view — the number the evening ramp is scheduled against.
California operates the largest grid-scale solar fleet in the country — around twenty gigawatts, before counting rooftops. At midday it routinely serves a third or more of demand, which is what carves the duck curve: net load collapses at noon and surges at sunset. Every other number in this market — prices, batteries, gas dispatch — arranges itself around this curve.
Solar forecast error in California is mostly a cloud story: marine layer on the coast, monsoon cloud in the desert. The scorecard below sizes the miss over the settled window — and a morning the marine layer holds an hour longer than forecast is real money at the ramp.
curl "https://askthegrid.com/api/v1/grid/radar/curves?iso=CAISO&horizon=extended"
Connect your agent to mcp.askthegrid.com and this forecast is a tool call away — the same host Claude and ChatGPT connectors already use.
Around twenty gigawatts of utility-scale capacity on the CAISO grid, plus a rooftop fleet nearly as large that shows up as suppressed demand rather than generation. At midday the utility-scale fleet alone routinely covers a third of the state's needs.
The shape of California's net load: demand minus solar. Solar floods the middle of the day, so net load sags at noon and then climbs at the fastest sustained rate on any US grid as the sun sets — the curve looks like a duck's back and neck. This forecast is the supply side of that shape.
On clear days, very — solar geometry is deterministic. The misses come from clouds: coastal marine layer that burns off late, and summer monsoon cover in the desert. The scorecard above puts numbers on the recent record rather than generalizing.
Plotted window Aug 27, 10:00 PM PDT → Aug 30, 12:00 AM PDT. Reissued continuously through the operating day; the latest vintage is shown.
| Fri, 8/28 |
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| Sat, 8/29 |
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| Sun, 8/30 |
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Darkest cells are the tightest hours. The window peaks at 19,662 MW on Sat, 12 PM, local to the market.