Average daily sunspot numbers for the past week declined from 114.6 to 107.4, and average solar flux went from 138.8 to 139.2. This is comparing the period from December 26 through January 1 with the previous seven days.
The average daily sunspot number for the entire year of 2013 was 97.1, the highest since 2003. For 2008-2013 the yearly average was 4.7, 5.1, 25.5, 80.1, 82.3 and 97.1.
We’ve als…
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Sunspot numbers made a profound leap over the past week, with the sunspot number on November 15 reaching 272, then 282 on November 17. This is a record for the current solar cycle, and this level of activity has not been observed for over a decade. Unfortunately the sunspot number declined rapidly since then, falling below 100.
You can check in the ARRL Propagation Bulletin archives to see what …
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Solar activity remains robust. Yesterday, Thursday, November 14 the daily sunspot number rose to 234, a number not seen since the last blast of the second peak of the previous solar cycle, exactly a decade ago.
Way back on October 27 through November 1, 2003 the daily sunspot numbers were 238, 230, 330, 293, 266, and 277. That was it. Nothing as high as a sunspot number of 234 since then.
But the…
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It’s been a lively couple of weeks, with plenty of sunspots and great HF propagation. Average daily sunspot number for the week was 161.6, unchanged from last week’s average of 162. Solar flux values were up quite a bit though, rising from 139.6 to 158.3, quite a healthy jump.
On October 26 the Penticton solar flux reading was 171.8, but NOAA downgraded it to 165, probably because the higher val…
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Solar activity was very, very quiet over the past week. For the reporting period September 5-11, the average daily sunspot number was only 37.7. Average daily sunspot numbers as reported in this bulletin have not been nearly this low since June 6-12 of this year, when it was 39.6. The last time it was lower was June 21-27 of last year, when it was 26.3.
Australia’s IPS Radio and Space Services i…
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Solar activity slipped this week, with the average daily sunspot number declining nearly 50 points to 77 and average daily solar flux down nearly 10 points to 116.4. In fact, those “nearly” numbers were 49.9 and 9.9.
The latest solar flux predictions from NOAA/USAF (Thursday, August 29, 2013):
August 30-September 1: 108, 105 and 108
September 2-3: 110
September 4-5: 112
September 6-7: 115 and 120
Se…
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Solar activity remains quiet, but on May 16 the daily sunspot number reached 212. I had to keep searching further and further back in the records to find a higher sunspot number. One year, six months and one week earlier — November 9, 2011 — the sunspot number was almost that high, at 208. Going back seven years, 10 months and 12 days to July 4, 2005, it was 192. To find activity beating the …
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Solar activity was quiet this week: The average daily sunspot number declined nearly 23 points to 90.6, while the average daily solar flux values were down nearly 13 points to 109.1. The most active day was April 24, with a planetary A index of 19 and mid-latitude A index of 15. The average daily mid-latitude A index was the same this week as last, 4.9. Sunspot numbers for April 18-24 were 86, …
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Both the average daily sunspot numbers and the solar flux were up this week, with the sunspot numbers rising nearly 57 points to 138.1, and the average daily solar flux up more than 25 points to 138.8. Paired with the average daily planetary A index dropping from 9.4 to 4.1, this is great news for HF propagation. On April 8, the daily sunspot number reached 162; two days later, it was at 163. T…
American Radio Relay League | Ham Radio Association and Resources
Solar activity was down this week, with the average daily sunspot number at 49.6, less than half last week’s figure. The average daily solar flux dropped 22 points to 97, and geomagnetic activity was quiet also. Sunspot numbers for March 21-27 were 60, 54, 56, 45, 56, 41 and 35, with a mean of 49.6. The 10.7 centimeter flux was 106.1, 100.9, 98.2, 96, 92.6, 92.4 and 93, with a mean of 97. The e…
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This past week, there was a decline in the solar and geomagnetic indices: The average daily sunspot number dropped nearly 21 points to 57.7, while the average daily solar flux softened by 4.7 points to 100.9 and the average daily planetary A index declined 6.4 points to 5.1. This isn’t much of a change, but geomagnetic activity was low already, and this is even lower.
Sunspot numbers for Februar…
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Solar activity continues at the low levels that we have seen in the past few weeks. The sunspot numbers have been remarkably consistent, with the average daily numbers for the weeks since January 17 at 56.4, 55.7, 50.7 and finally 51.3 for this past week. As you can see, the average daily sunspot number rose less than 1 point from the previous week to the past week, while the average daily sola…
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The average daily sunspot number for the week was down nearly 38 percent to 78.9, compared to last week’s average of 126.9. The average daily solar flux dropped nearly 13 percent, to 121 from 138.9. The seven-day reporting period for these data ran from November 22-28. Sunspot numbers for November 22-28 were 93, 85, 87, 64, 81, 76 and 66, with a mean of 78.9. The 10.7 centimeter flux was 127.7,…
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In November 16 edition of the Solar Update, we reported that the average daily sunspot number on November 8-14 was 104.9. In the next seven day reporting period — November 15-21 — the average was 126.9, making for a nice increase; with solar flux, the average over the previous period was 129.5. In the most recent period, the average daily sunspot number increased to 138.9. In the four days si…
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There has been an exciting and dramatic rise in sunspot activity this week. The daily sunspot number was 188 on Monday, November 12 — higher than it has been in more than a year. The last time the daily sunspot number was as high was on November 9, 2011, when it was 208. Prior to last November, we have to go back nine years — November 26, 2003 — into the previous solar cycle to find a number…
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Sunspot activity continued to drop until early this week: The average daily sunspot numbers were 26.3, down more than 58 points from last week’s numbers, while the average daily solar flux declined to 92.8, down over 33 points from last week’s average. The weekly sunspot number average has declined since the May 31-June 6 period, when it was 130.4, followed by 116.1 the next week, 84.6 the next…
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The average daily sunspot numbers for the past week rose nearly 25 points, or about 27 percent, to 117.3. The big day was Monday, May 14 when the daily sunspot number jumped to 156. This was the day after four new sunspot groups, numbered 1481 through 1484 arrived. Sunspot numbers for May 10-16 were 93, 102, 85, 138, 156, 125 and 122, with a mean of 117.3. The 10.7 cm flux was 130.7, 136.4, 129…
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Solar activity revived over the past week, with a big increase in sunspot numbers. On Friday, April 20, the daily sunspot number reached 162; four days later on April 24, the number reached 169. This level of activity has not been seen since last fall, when the daily sunspot number reached 173 on September 16, 184 on October 21 and 208 on November 9.
The average daily sunspot numbers more than d…
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The bulletin appears a day early this week because ARRL Headquarters is closed for the Good Friday holiday.
Over the past week, the average daily sunspot number and solar flux values rose slightly, even though as the week progressed, each day had a lower number than the day before. The daily sunspot number began the week at a high of 100, but ended at 60. Likewise, the daily solar flux started a…
American Radio Relay League | Ham Radio Association and Resources
Eight new sunspot groups appeared this week, but the average daily sunspot number declined four points to 71.1; the average daily solar flux rose by less than two points to 103.7. Sunspot numbers for March 22-28 were 86, 74, 65, 84, 56, 63 and 70, with a mean of 71.1. The 10.7 cm flux was 102.4, 104.8, 102.7, 101.3, 102.4, 105.6 and 107, with a mean of 103.7. The estimated planetary A indices w…
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