Starburst Meadows Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Starburst Meadows Observatory clear sky chart from 2005-11-06 to 2024-01-13.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
29%
22919
17%
74922
8%
22877
40%
22877
19%
49728

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 10thNight
19%
760
19%
2649
6%
757
35%
757
18%
1669
January11th to 20thNight
17%
729
15%
2549
3%
729
30%
729
11%
1794
January21st to endNight
17%
792
20%
2772
6%
792
35%
792
17%
1744
February1st to 10thNight
18%
720
16%
2361
5%
720
31%
720
14%
1631
February11th to 20thNight
16%
703
20%
2100
4%
700
34%
700
17%
1432
February21st to endNight
21%
592
23%
1776
9%
592
39%
592
20%
1172
March1st to 10thNight
18%
720
20%
2160
6%
720
36%
720
19%
1469
March11th to 20thNight
22%
720
17%
2015
6%
720
32%
720
18%
1390
March21st to endNight
23%
792
22%
2130
7%
792
34%
792
23%
1432
April1st to 10thNight
21%
720
18%
1800
4%
720
30%
720
21%
1306
April11th to 20thNight
29%
616
18%
1680
7%
616
36%
616
25%
1140
April21st to endNight
28%
540
15%
1620
6%
540
35%
540
17%
1148
May1st to 10thNight
28%
540
13%
1620
7%
540
34%
540
18%
1165
May11th to 20thNight
28%
527
15%
1589
8%
527
36%
527
18%
1130
May21st to endNight
36%
389
13%
1551
15%
388
42%
388
14%
1060
June1st to 10thNight
37%
360
12%
1440
12%
360
45%
360
13%
1011
June11th to 20thNight
44%
360
11%
1440
14%
360
49%
360
19%
905
June21st to endNight
42%
360
9%
1440
11%
360
47%
360
16%
980
July1st to 10thNight
51%
350
11%
1400
16%
350
54%
350
19%
889
July11th to 20thNight
49%
348
13%
1392
19%
348
53%
348
19%
886
July21st to endNight
55%
394
15%
1486
18%
372
58%
372
21%
913
August1st to 10thNight
54%
510
14%
1574
11%
508
56%
508
25%
1004
August11th to 20thNight
50%
532
17%
1596
13%
532
52%
532
24%
1063
August21st to endNight
51%
689
21%
1877
11%
689
56%
689
31%
1217
September1st to 10thNight
46%
720
19%
1845
8%
720
52%
720
33%
1207
September11th to 20thNight
41%
720
22%
1980
12%
720
49%
720
33%
1239
September21st to endNight
45%
720
24%
1980
14%
720
53%
720
31%
1249
October1st to 10thNight
40%
720
18%
1980
11%
720
45%
720
23%
1340
October11th to 20thNight
33%
720
21%
2218
9%
720
45%
720
23%
1450
October21st to endNight
24%
792
16%
2574
8%
792
35%
792
17%
1757
November1st to 10thNight
31%
740
22%
2407
12%
740
45%
740
22%
1508
November11th to 20thNight
24%
760
24%
2470
10%
760
43%
760
21%
1558
November21st to endNight
23%
761
21%
2471
6%
761
39%
761
19%
1576
December1st to 10thNight
18%
850
17%
2807
4%
850
32%
850
16%
1945
December11th to 20thNight
19%
826
18%
3356
4%
825
34%
825
14%
2118
December21st to endNight
16%
827
13%
4817
3%
817
32%
817
9%
3231

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
18%7%35%5%3445%7%39%
74450
Night
19%8%35%5%3445%6%39%
75259
TransparencyDay
44%6%12%22%14%2
74155
Night
45%6%11%22%14%2
75089
SeeingDay
21%14%33%22%8%2
13876
Night
22%12%31%26%9%1
22928

By Month

Percentage Cloud Cover NE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
16%8%45%5%34346%42%
1517
11th to 20thDay
20%7%25%4345%47%38%
1456
21st to endDay
14%10%35%435%5%5%6%40%
1584
February1st to 10thDay
19%9%35%5%35%5%5%6%36%
1598
11th to 20thDay
14%8%36%6%45%5%5%6%37%
1748
21st to endDay
16%11%46%5%3445%6%35%
1480
March1st to 10thDay
17%8%36%5%45%447%38%
1797
11th to 20thDay
17%7%36%5%33437%42%
1944
21st to endDay
17%8%36%5%24445%42%
2222
April1st to 10thDay
20%8%36%6%2445%6%36%
2160
11th to 20thDay
19%5%25%5%35%45%7%40%
2228
21st to endDay
24%7%25%5%3445%6%34%
2340
May1st to 10thDay
25%7%35%5%24447%34%
2340
11th to 20thDay
19%7%35%6%2445%7%38%
2321
21st to endDay
19%5%35%5%35%45%8%37%
2725
June1st to 10thDay
23%7%35%5%3445%7%33%
2520
11th to 20thDay
17%6%25%5%35%448%40%
2520
21st to endDay
22%7%35%5%35%5%5%8%32%
2520
July1st to 10thDay
16%6%245%36%5%6%9%38%
2520
11th to 20thDay
14%6%25%5%35%6%7%10%37%
2520
21st to endDay
14%4246%35%6%6%9%40%
2744
August1st to 10thDay
12%5%25%5%36%5%7%10%41%
2334
11th to 20thDay
14%5%35%5%35%5%6%10%39%
2304
21st to endDay
13%4145%35%6%6%8%45%
2476
September1st to 10thDay
13%42443445%8%48%
2114
11th to 20thDay
13%6%24423346%55%
1980
21st to endDay
17%6%244245%47%45%
1980
October1st to 10thDay
19%7%45%5%34346%40%
1980
11th to 20thDay
18%6%36%5%34336%42%
1739
21st to endDay
23%9%25%424445%40%
1782
November1st to 10thDay
18%6%33423346%48%
1671
11th to 20thDay
21%42442345%7%45%
1710
21st to endDay
22%8%24422346%43%
1702
December1st to 10thDay
23%8%345%3443438%
1368
11th to 20thDay
22%9%34323345%42%
1734
21st to endDay
26%9%36%5%34446%31%
2772
January1st to 10thNight
16%9%35%43345%6%41%
2649
11th to 20thNight
18%11%37%5%35%5%46%33%
2549
21st to endNight
13%9%36%5%34446%41%
2772
February1st to 10thNight
18%9%35%6%36%45%6%35%
2361
11th to 20thNight
14%10%36%6%45%45%5%40%
2098
21st to endNight
15%10%45%5%3435%6%41%
1776
March1st to 10thNight
14%11%45%5%35%446%38%
2150
11th to 20thNight
17%7%36%6%3445%7%37%
2014
21st to endNight
19%7%35%42345%5%43%
2130
April1st to 10thNight
22%9%25%5%35%346%36%
1800
11th to 20thNight
19%5%25%5%35%6%5%7%39%
1680
21st to endNight
24%6%35%6%345%46%34%
1620
May1st to 10thNight
21%9%36%445%6%6%7%30%
1620
11th to 20thNight
19%9%25%5%346%6%8%31%
1588
21st to endNight
20%9%47%5%2445%6%34%
1550
June1st to 10thNight
23%7%37%5%345%5%6%32%
1440
11th to 20thNight
18%7%35%5%25%45%8%39%
1440
21st to endNight
23%7%36%435%46%7%33%
1440
July1st to 10thNight
16%6%345%45%6%5%8%37%
1440
11th to 20thNight
16%7%35%6%35%47%10%35%
1440
21st to endNight
16%4245%35%7%6%9%38%
1574
August1st to 10thNight
12%5%26%5%35%5%7%7%42%
1584
11th to 20thNight
16%6%36%5%35%5%7%9%36%
1596
21st to endNight
15%6%145%3445%7%47%
1877
September1st to 10thNight
13%6%25%43345%6%49%
1845
11th to 20thNight
16%7%14323346%50%
1980
21st to endNight
15%6%2443345%6%48%
1980
October1st to 10thNight
20%6%25%4245%5%6%40%
1980
11th to 20thNight
18%6%25%5%35%45%7%41%
2218
21st to endNight
26%6%25%434445%37%
2574
November1st to 10thNight
17%6%245%34446%45%
2407
11th to 20thNight
19%5%24435%45%7%43%
2470
21st to endNight
17%7%35%434447%43%
2471
December1st to 10thNight
22%10%35%43445%5%36%
2807
11th to 20thNight
22%7%2443445%5%41%
3455
21st to endNight
25%10%36%5%3434434%
4884

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
44%6%10%24%15%1
1518
11th to 20thDay
47%8%12%20%12%2
1456
21st to endDay
43%5%11%22%16%2
1584
February1st to 10thDay
48%6%12%19%13%2
1598
11th to 20thDay
46%6%14%18%13%3
1757
21st to endDay
49%410%19%14%4
1480
March1st to 10thDay
47%412%18%15%5%
1800
11th to 20thDay
43%410%22%16%5%
1944
21st to endDay
45%5%8%18%18%6%
2222
April1st to 10thDay
49%6%9%17%15%4
2160
11th to 20thDay
43%6%11%23%15%3
2228
21st to endDay
51%5%9%17%14%4
2340
May1st to 10thDay
51%6%8%19%15%2
2340
11th to 20thDay
45%5%10%20%17%3
2325
21st to endDay
45%9%13%19%12%2
2725
June1st to 10thDay
50%6%12%22%9%
2520
11th to 20thDay
44%6%11%21%16%2
2520
21st to endDay
50%8%12%20%9%1
2520
July1st to 10thDay
40%8%14%23%14%1
2450
11th to 20thDay
41%8%15%24%11%1
2445
21st to endDay
38%8%17%24%12%1
2591
August1st to 10thDay
36%10%17%27%10%
2320
11th to 20thDay
38%8%17%24%12%1
2304
21st to endDay
34%8%14%24%18%2
2476
September1st to 10thDay
34%7%15%27%17%1
2114
11th to 20thDay
32%5%10%28%23%2
1980
21st to endDay
39%6%10%27%18%1
1980
October1st to 10thDay
45%5%10%23%15%2
1980
11th to 20thDay
44%5%12%28%11%1
1739
21st to endDay
48%5%10%21%14%2
1782
November1st to 10thDay
39%413%25%16%3
1671
11th to 20thDay
39%5%11%23%19%4
1710
21st to endDay
44%317%21%13%1
1702
December1st to 10thDay
51%410%21%12%2
1368
11th to 20thDay
46%410%21%15%5%
1734
21st to endDay
55%6%10%17%9%3
2772
January1st to 10thNight
44%413%24%13%2
2649
11th to 20thNight
52%7%12%18%10%1
2549
21st to endNight
44%49%23%17%2
2772
February1st to 10thNight
50%5%12%18%13%2
2361
11th to 20thNight
48%49%21%15%3
2100
21st to endNight
45%410%22%15%5%
1776
March1st to 10thNight
47%5%8%21%16%3
2160
11th to 20thNight
47%5%11%17%15%4
2015
21st to endNight
44%48%19%20%5%
2130
April1st to 10thNight
50%5%8%18%16%4
1800
11th to 20thNight
44%5%10%22%17%1
1680
21st to endNight
51%6%10%17%12%4
1620
May1st to 10thNight
51%7%9%18%13%2
1620
11th to 20thNight
49%8%10%18%12%3
1589
21st to endNight
51%7%11%18%12%2
1551
June1st to 10thNight
53%8%9%20%10%1
1440
11th to 20thNight
44%6%14%19%15%2
1440
21st to endNight
50%7%14%20%9%
1440
July1st to 10thNight
42%8%15%20%13%1
1400
11th to 20thNight
44%8%13%26%11%
1392
21st to endNight
40%8%15%25%10%1
1486
August1st to 10thNight
37%10%15%27%10%1
1574
11th to 20thNight
42%8%14%23%13%
1596
21st to endNight
37%7%10%27%18%1
1877
September1st to 10thNight
36%7%12%28%16%1
1845
11th to 20thNight
36%5%10%27%19%2
1980
21st to endNight
37%6%11%29%16%2
1980
October1st to 10thNight
44%6%11%23%15%2
1980
11th to 20thNight
43%6%11%27%13%1
2218
21st to endNight
49%5%10%20%14%1
2574
November1st to 10thNight
41%5%10%26%16%2
2407
11th to 20thNight
42%5%10%23%17%3
2470
21st to endNight
42%5%14%22%15%2
2471
December1st to 10thNight
51%5%10%21%13%1
2807
11th to 20thNight
44%5%12%21%17%1
3456
21st to endNight
53%5%11%19%11%1
4884

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 10thDay
23%26%27%19%6%
180
11th to 20thDay
27%20%25%23%5%1
164
21st to endDay
16%21%38%19%6%
176
February1st to 10thDay
28%15%36%19%2
318
11th to 20thDay
21%22%40%15%1
416
21st to endDay
22%18%38%18%4
346
March1st to 10thDay
22%17%39%17%3
420
11th to 20thDay
19%23%40%15%21
420
21st to endDay
22%23%32%14%6%3
462
April1st to 10thDay
26%21%31%16%42
420
11th to 20thDay
23%18%33%17%6%2
412
21st to endDay
30%14%34%17%42
420
May1st to 10thDay
27%18%31%17%5%1
423
11th to 20thDay
19%14%43%16%6%1
447
21st to endDay
22%12%35%25%5%2
485
June1st to 10thDay
21%13%34%24%7%2
450
11th to 20thDay
17%12%38%22%8%2
450
21st to endDay
23%8%34%24%9%1
450
July1st to 10thDay
20%5%33%29%11%2
445
11th to 20thDay
15%5%32%32%13%3
444
21st to endDay
14%433%33%13%3
488
August1st to 10thDay
14%5%30%33%15%3
446
11th to 20thDay
16%5%29%30%13%6%
439
21st to endDay
13%7%31%29%16%4
495
September1st to 10thDay
16%6%30%29%15%4
450
11th to 20thDay
16%9%33%23%12%6%
450
21st to endDay
18%10%31%24%12%5%
450
October1st to 10thDay
22%14%23%25%12%4
450
11th to 20thDay
21%14%28%23%10%3
363
21st to endDay
30%12%27%22%9%1
396
November1st to 10thDay
19%18%27%24%9%2
365
11th to 20thDay
24%18%31%21%6%1
370
21st to endDay
25%19%27%22%6%1
370
December1st to 10thDay
25%15%36%16%7%
218
11th to 20thDay
26%26%30%15%4
180
21st to endDay
26%24%28%16%6%1
198
January1st to 10thNight
20%20%35%21%4
760
11th to 20thNight
24%18%35%19%4
729
21st to endNight
18%20%38%20%3
792
February1st to 10thNight
22%19%34%22%3
720
11th to 20thNight
21%19%38%19%2
703
21st to endNight
20%18%35%22%5%
592
March1st to 10thNight
22%17%39%20%2
720
11th to 20thNight
22%15%35%20%8%
720
21st to endNight
22%15%34%23%5%1
792
April1st to 10thNight
27%14%35%20%5%
720
11th to 20thNight
20%11%35%27%6%
616
21st to endNight
27%10%29%27%6%1
540
May1st to 10thNight
24%8%32%26%8%2
540
11th to 20thNight
25%8%33%27%7%
527
21st to endNight
27%5%23%33%12%1
389
June1st to 10thNight
28%6%22%31%12%2
360
11th to 20thNight
21%326%35%15%1
360
21st to endNight
26%323%36%12%1
360
July1st to 10thNight
20%5%18%41%16%1
350
11th to 20thNight
18%122%37%20%2
348
21st to endNight
17%317%41%21%1
394
August1st to 10thNight
15%320%42%19%1
510
11th to 20thNight
16%420%39%20%2
532
21st to endNight
16%421%36%21%2
689
September1st to 10thNight
15%228%34%20%1
720
11th to 20thNight
18%6%29%26%18%3
720
21st to endNight
17%6%25%31%17%3
720
October1st to 10thNight
23%8%23%27%17%1
720
11th to 20thNight
20%11%31%26%11%2
720
21st to endNight
29%11%29%23%7%
792
November1st to 10thNight
20%11%32%28%7%2
740
11th to 20thNight
22%15%34%21%7%1
760
21st to endNight
21%18%33%22%5%
761
December1st to 10thNight
27%14%36%17%6%
850
11th to 20thNight
24%19%33%21%3
826
21st to endNight
27%16%35%19%3
836
Page generated at 2024-01-10 01:25:01. Version ac07

Copyright 2024 Attilla Danko


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