Daily Solar Data

On this page, you’ll find daily solar data which is more or less in real-time. The data is sourced directly from NOAA via a live JSON feed, so every time you refresh this page, the feed will also be refreshed and tables updated if NOAA has updated the feed. You’ll also find detailed solar region information.

Solar regions are numbered, and further down the page, you’ll see a current image of the sun that shows where the regions are.

The table shows the region’s size (area), the number of spots in the region, the magnetic characterisation of the spot, along with the chance of a C, M and X class flare. The table below that shows the level of Solar Flux (SFI) which is the key indicator for HF radio propagation, and below that are SFI levels over the past few weeks.

There is more general information on the space weather page.

Solar Flux Index (SFI) over the past month

The graph below highlights the Solar Flux (SFI) over the past month. For good DX, the solar flux should remain above about 150 for a few days with the K index below 2. The k index will rise after a solar flare. This graph is almost real-time and is sourced from NOAA.

Solar Flux @2800 MHz

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Numbers for good DX

Solar Regions

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Visit the AAVSO page for more information about sunspot classifications.

Fun Fact…

Solar Flux (SFI) is a simple measurement which is immediately available, unlike the SunSpot Number (SSN) which requires processing. The solar flux is measured at several frequencies, the value at 2800MHz being considered the best measure. There is a correlation between the SSN and the flux but the widely scattered points show that this is an approximate relationship and not the simple curve shown, which is often assumed in MUF predictions.

The SFI  is one of the longest running records of solar activity. The 2800 MHz radio emissions originate high in the chromosphere and low in the corona of the solar atmosphere. It correlates well with the sunspot number as well as a number of UltraViolet (UV) and visible solar irradiance records. It’s been measured consistently in Canada since 1947. Unlike many solar indices, the F10.7 radio flux can easily be measured reliably on a day-to-day basis from the Earth’s surface, in all types of weather. It’s reported in “solar flux units”, (SFU), and can vary from below 50 to above 300 over the course of a solar cycle.


Solar cycles over the ages






This channel highlights the outer atmosphere of the Sun – called the corona – as well as hot flare plasma. Hot active regions, solar flares, and coronal mass ejections will appear bright here. The dark areas – called coronal holes – are places where very little radiation is emitted, yet are the main source of solar wind particles.