Solar Forecasting and PV Production Guides

Your solar forecast is off: 5 checks, in order

Before blaming the model, rule out the four things that look like forecast error and are not. Then one test tells you whether it was really the weather.

Sep 15, 2026 · 5 min read

When the Sahara Dims Your Panels: Dust Events and Solar Output

Saharan dust can cut solar output under a clear sky and leave a film that lingers for weeks. What dust events do to production and forecasts.

Aug 11, 2026 · 2 min read

Coast or Inland? How Local Microclimate Shapes Your Solar Output

Two identical systems 50 km apart can produce quite differently. How coastal fog, sea breeze, and humidity change your solar yield.

Aug 4, 2026 · 2 min read

Why a Global Forecast Isn't Enough for Solar

Global weather models smear out the clouds that decide your solar output. Here is why regional models matter for an accurate forecast.

Jul 28, 2026 · 2 min read

Best solar forecast app — what actually predicts your output

Inverter app, weather app or a dedicated forecast app? Which apps actually predict tomorrow's solar output — an honest overview with a recommendation.

Jul 23, 2026 · 2 min read

Dynamic electricity tariffs with solar — is it worth it?

Hourly prices, export rates and storage: who wins on a dynamic tariff with solar — with a real day-in-the-life example from a prosumer household.

Jul 23, 2026 · 3 min read

Charging your EV from solar — when to plug in the car

How to charge your EV on solar surplus: power thresholds, charger modes, and planning charge sessions with an hourly production forecast.

Jul 23, 2026 · 2 min read

Heat pump + solar — matching heating to your production

How to shift heat pump hot-water cycles into your solar production peak — schedules, smart-grid inputs and forecast-driven automation.

Jul 23, 2026 · 3 min read

Home Assistant solar forecast: 3 sources compared

Forecast.Solar, Solcast or Volcast? Accuracy, API limits and setup of PV forecasting in Home Assistant, honestly compared — with a step-by-step guide.

Jul 23, 2026 · 4 min read

Home battery — when to charge from grid vs solar

Cheap overnight grid charging vs storing midday sun: when each strategy pays, with worked examples — and where a production forecast fits in.

Jul 23, 2026 · 2 min read

Increase solar self-consumption — 7 proven ways to use more of your own power

Exported solar earns cents; self-consumed solar saves full retail. Seven proven ways to use more of your own power — from timing to automation.

Jul 23, 2026 · 3 min read

Negative electricity prices — what solar owners should know

Why power prices go negative, what it means for your export earnings — and how to avoid paying to export on sunny middays.

Jul 23, 2026 · 2 min read

Solar in winter — what your system really produces

Real winter yields from a 5.2 kWp system, month by month — and how to spot the few sunny windows worth shifting your consumption into.

Jul 23, 2026 · 3 min read

Solar production forecasting — how to predict tomorrow's PV output accurately

How much power will your solar system produce tomorrow? Physics models, weather-model data and calibration — how accurate PV forecasting actually works.

Jul 23, 2026 · 5 min read

Volcast vs Forecast.Solar vs Solcast — an honest comparison

The three most popular solar forecast sources compared honestly: accuracy, calibration, apps, free-tier limits and pricing — with a self-test method.

Jul 23, 2026 · 3 min read

Why weather apps can't tell you your solar output

"Sunny" doesn't mean "lots of power". Irradiance vs cloud cover, roof geometry and temperature — why panels need their own forecast, explained simply.

Jul 23, 2026 · 3 min read

Best time to run washing machine and water heater on solar

What time should the water heater and appliances run to use your own solar power? A simple rule, hourly examples, and how to automate it.

Jul 23, 2026 · 4 min read

Why the Same Solar System Produces Differently Across Europe

A 5 kWp array in Madrid can out-produce the same system in Warsaw by half. Here is what latitude and climate do to your solar yield.

Jul 21, 2026 · 2 min read

Too Much Sun? Curtailment, Negative Prices, and Your Summer Surplus

Too much sun in summer? Clipping, curtailment, negative prices, and how to turn your midday surplus into real savings.

Jun 16, 2026 · 3 min read

Why Your Solar Panels Produce Less on the Hottest Days

Heat is the enemy of solar output. Here is the physics of temperature derating, and why a cool spring day can beat a scorching one in July.

Jun 9, 2026 · 3 min read

Why New Installations Don't Need Training Data With Physics-Based Models

Most forecast tools need months of history before they work. Physics-based forecasting works from day one. Here's why — and what that means for new PV owners.

May 26, 2026 · 5 min read

Nowcasting vs Day-Ahead vs Weekly — Accuracy at Every Time Horizon

A 15-minute forecast and a 7-day forecast are fundamentally different problems. Here's what each time horizon can realistically deliver and where accuracy breaks down.

May 19, 2026 · 5 min read

Transposition Models: How Volcast Calculates What Hits Your Tilted Panel

Weather data tells us what reaches a horizontal surface. Your panels are tilted. The mathematical bridge between the two is called transposition — and the choice of model matters.

May 12, 2026 · 5 min read

The Irradiance Journey: From Space to Your Solar Panel in 8 Steps

Follow a beam of sunlight from the edge of Earth's atmosphere through scattering, absorption, clouds, and reflection until it reaches your tilted panel and becomes electricity.

May 5, 2026 · 5 min read

Why Cloud Cover Is the Hardest Variable in Solar Prediction

Temperature is predictable. Sun position is calculable. But clouds? Clouds are chaos theory in action — and the single biggest source of solar forecast error.

Apr 28, 2026 · 5 min read

Where Weather Forecasts Come From: NWP Models Explained for PV Owners

Your solar forecast is only as good as its weather input. Here's how numerical weather prediction models work, what they get right, and where they fall short for solar energy.

Apr 21, 2026 · 5 min read

Physics-Based vs ML-Based Solar Forecasting — Why the Approach Matters

Two fundamentally different approaches to predicting solar production. One models the physics, the other learns from data. Here's why the distinction matters for your forecast.

Apr 14, 2026 · 6 min read