Overview

Historical weather API

High-resolution & accurate historical solar irradiance and weather data built for solar

Historical weather data to power your solar decisions

Access the world’s most accurate historical irradiance and weather data through our historical weather API. The Solcast API provides 20+ weather parameters tailored to solar energy applications, from 2007 to 7 days ago. Available instantly via synchronous JSON API or as an instant CSV web download.

CLOUD AND IRRADIANCE TRACKING

Tracking the world's clouds in the finest detail

Designed for solar, from the ground up. Never rely on generic weather model data again. Solcast’s real-time, forecast, and historical weather API track real clouds at 1–2 km and 5-minute resolution. Irradiance and PV power data update every 5 minutes and are downscaled to 90-metre resolution, with explicit modeling of aerosol and albedo effects.

WEATHER DATA

Full suite of high resolution weather data

Access high-resolution weather and irradiance data for any global location via our historical weather API as part of the Solcast API.

Weather data from leading reanalysis datasets completes the full suite of 20+ parameters available at 5, 10, 15, 30 and 60 minute resolutions. Coverage from 2007 to 7 days ago.

VALIDATION

Upfront, transparent accuracy and validation

Be confident that our data is fit for purpose.

Our team of meteorologists and data scientists publish site-by-site validation so you can trust the performance of our historical weather API outputs.

Review global, regional and climate-zone results in our bankability validation.

DATA ACCESS

Get data via synchronous API or instant CSV download

Our synchronous historical weather API returns JSON within 1–5 seconds per request.

Requests can be run in parallel up to your account’s rate limit.

Web downloads allow up to 20 locations at a time across multiple formats, including CSV ready for common simulation tools.

Product specifications

Geographic covereage

Global (note: far ocean and polar regions are coarser resolution)

Temporal coverage

January 2007 to 7 days ago (for past 7 days to present time and forecasts, use our Live and Forecast data)

Temporal resolution

5, 10, 15, 30 & 60 minutes (period-mean values)

Spatial resolution

90 meters (irradiance, PV power, snow soiling, cloud parameters, andother parameters across all regions)

Data parameters

The following data parameters are available.

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Irradiance Parameters


  • Global Horizontal Irradiance*^ (GHI) (W/m2)
  • Direct Normal Irradiance*^ (DNI) (W/m2)
  • Diffuse Horizontal Irradiance*^ (DHI) (W/m2)
  • Global Tilted Irradiance*^ (GTI) (W/m2)

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Solar Parameters

  • Global Horizontal Irradiance*^ (GHI) (W/m2)
  • Direct Normal Irradiance*^ (DNI) (W/m2)
  • Diffuse Horizontal Irradiance*^ (DHI) (W/m2)
  • Global Tilted Irradiance*^ (GTI) (W/m2)

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Weather Parameters


  • Global Horizontal Irradiance*^ (GHI) (W/m2)
  • Direct Normal Irradiance*^ (DNI) (W/m2)
  • Diffuse Horizontal Irradiance*^ (DHI) (W/m2)
  • Global Tilted Irradiance*^ (GTI) (W/m2)

Data access

API or Web download

Download wait time

API: synchronous requests. Web download: seconds.

File formats

CSV, JSON, PVsyst, SAM, TMY3

Data formats

Solcast standard, PVsyst (60 minute only)

Time zone

UTC, longitudinal, or user-specified fixed offset.

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Lithuania

Luxembourg

Madagascar

Malawi

Malaysia

Maldives

Mali

Malta

Marshall Islands

Mauritania

Mauritius

Mexico

Micronesia

Moldova

Monaco

Mongolia

Montenegro

Morocco

Mozambique

Myanmar (formerly Burma)

Namibia

Nauru

Nepal

Netherlands

New Zealand

Nicaragua

Niger

Nigeria

North Korea

North Macedonia

Norway

Oman

Pakistan

Palau

Palestine State

Panama

Papua New Guinea

Paraguay

Peru

Philippines

Poland

Portugal

Qatar

Romania

Russia

Rwanda

Saint Kitts and Nevis

Saint Lucia

Saint Vincent and the Grenadines

Samoa

San Marino

Sao Tome and Principe

Saudi Arabia

Senegal

Serbia

Seychelles

Sierra Leone

Singapore

Slovakia

Slovenia

Solomon Islands

Somalia

South Africa

South Korea

South Sudan

Spain

Sri Lanka

Sudan

Suriname

Sweden

Switzerland

Syria

Taiwan

Tajikistan

Tanzania

Thailand

Timor-Leste

Togo

Tonga

Trinidad and Tobago

Tunisia

Turkmenistan

Tuvalu

Uganda

Ukraine

United Arab Emirates

United Kingdom

United States of America

Uruguay

Uzbekistan

Vanuatu

Venezuela

Vietnam

Yemen

Zambia

Zimbabwe

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Check how Solcast Historical Time Series compares with other irradiance and weather data.

Frequently asked questions about our historical weather API

What is a Historical Weather API?

A Historical Weather API provides past weather and irradiance data—such as GHI, DNI, temperature, cloud cover, and wind—delivered programmatically via JSON or downloadable files. Solcast’s Historical Weather API offers high-resolution, satellite-derived data from 2007 to 7 days ago, specifically tailored for solar energy applications.

What can I use historical weather data for?

Historical weather data is critical for solar projects, providing accurate resource assessment, long-term performance benchmarking and monitoring. Historical weather dat also enables gap-filling for missing sensor data.

How is time series data generated in the historical weather API?

Solcast uses an ensemble of global NWP weather data sources and historical satellite imagery to track clouds globally. Data is captured at native resolution from available data sources and downscaled to 90m based on terrain, aerosol and cloud data available.

How accurate is Solcast’s historical weather API?

Solcasts historical data has been validated as bankable by DNV in a global 207 site study. See the details in DNV's Bankability Report.

What locations are supported?

The Historical Weather API provides global coverage, with 90-metre irradiance resolution across all non-polar, continental regions and 27-kilometre resolution for other weather parameters and remote areas.

How does Solcast’s historical weather API compare with other providers?

The solcast API is built for the renewable energy industry. Some alternative weather APIs exist for general weather purposes, and some renewable energy data providers have APIs to access their data. Explore our historical and TMY data comparisons.

What time range does the historical dataset cover?

You can access data from January 2007 up to 7 days ago. This time horizon updates every 5 minutes For real-time and forecast data, use our Live Solar Data and Solar Forecast Data.