Renaissance Academy
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Renaissance Academy 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
43%
23796
20%
74625
13%
23750
51%
23750
25%
47199

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
26%
757
22%
2564
9%
757
43%
757
22%
1571
January11th to 20thNight
27%
732
21%
2378
9%
732
41%
732
18%
1583
January21st to endNight
23%
792
24%
2574
10%
792
41%
792
25%
1560
February1st to 10thNight
26%
720
18%
2340
10%
720
38%
720
22%
1509
February11th to 20thNight
17%
700
19%
2118
7%
700
32%
700
20%
1407
February21st to endNight
27%
592
27%
1776
13%
592
44%
592
24%
1131
March1st to 10thNight
30%
720
23%
2062
10%
720
45%
720
29%
1274
March11th to 20thNight
26%
720
18%
1980
8%
720
36%
720
23%
1362
March21st to endNight
31%
792
19%
2105
9%
792
39%
792
25%
1447
April1st to 10thNight
28%
720
20%
1800
6%
720
38%
720
28%
1216
April11th to 20thNight
40%
711
24%
1775
9%
711
47%
711
36%
1140
April21st to endNight
41%
720
20%
1800
8%
720
46%
720
32%
1191
May1st to 10thNight
38%
720
15%
1800
6%
720
41%
720
28%
1241
May11th to 20thNight
48%
485
16%
1547
11%
485
52%
485
24%
994
May21st to endNight
61%
388
17%
1551
18%
388
63%
388
22%
934
June1st to 10thNight
61%
360
17%
1440
21%
360
64%
360
24%
831
June11th to 20thNight
61%
360
13%
1440
14%
360
65%
360
21%
880
June21st to endNight
68%
360
17%
1440
20%
360
71%
360
23%
844
July1st to 10thNight
69%
350
16%
1400
19%
350
70%
350
21%
841
July11th to 20thNight
75%
456
16%
1500
16%
456
75%
456
29%
898
July21st to endNight
66%
591
16%
1672
14%
558
69%
558
27%
1100
August1st to 10thNight
66%
550
11%
1613
9%
547
66%
547
26%
1083
August11th to 20thNight
64%
710
15%
1774
9%
710
64%
710
27%
1249
August21st to endNight
61%
792
15%
1980
9%
792
62%
792
27%
1394
September1st to 10thNight
63%
720
22%
1800
15%
720
64%
720
32%
1203
September11th to 20thNight
60%
720
24%
1800
17%
720
62%
720
31%
1214
September21st to endNight
49%
720
18%
2019
14%
720
53%
720
22%
1427
October1st to 10thNight
54%
720
22%
2160
20%
720
59%
720
28%
1356
October11th to 20thNight
47%
720
25%
2160
21%
720
55%
720
29%
1323
October21st to endNight
44%
792
27%
2376
21%
792
55%
792
30%
1435
November1st to 10thNight
44%
740
23%
2320
17%
740
53%
740
27%
1421
November11th to 20thNight
37%
760
22%
2470
14%
760
48%
760
25%
1511
November21st to endNight
43%
760
26%
2501
19%
760
53%
760
29%
1450
December1st to 10thNight
30%
760
19%
2660
11%
760
42%
760
18%
1736
December11th to 20thNight
32%
760
22%
3175
13%
759
47%
759
20%
1866
December21st to endNight
34%
826
16%
4755
13%
817
48%
817
15%
2577

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
13%6%25%5%35%5%6%8%42%
74689
Night
14%6%25%5%3445%8%43%
75060
TransparencyDay
39%8%13%22%15%3
74401
Night
39%7%12%22%16%3
74867
SeeingDay
16%9%25%27%18%5%
14147
Night
16%8%26%32%16%2
23813

By Month

Percentage Cloud Cover SE (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
14%8%245%345%6%6%44%
1597
11th to 20thDay
16%6%36%5%3445%7%42%
1644
21st to endDay
14%8%35%324446%46%
1782
February1st to 10thDay
14%8%37%435%5%5%7%39%
1620
11th to 20thDay
19%6%25%5%34345%44%
1730
21st to endDay
16%8%35%5%2445%8%38%
1480
March1st to 10thDay
13%6%24424346%51%
1894
11th to 20thDay
17%7%2443445%7%43%
1980
21st to endDay
15%7%25%435%45%8%42%
2250
April1st to 10thDay
13%5%2343445%7%51%
2160
11th to 20thDay
10%5%245%345%6%7%49%
2134
21st to endDay
14%6%25%4345%6%7%45%
2160
May1st to 10thDay
14%5%245%345%7%8%43%
2160
11th to 20thDay
15%6%36%5%445%6%7%40%
2359
21st to endDay
13%6%35%435%5%6%9%41%
2725
June1st to 10thDay
10%5%245%35%6%8%12%40%
2520
11th to 20thDay
11%5%25%436%6%7%11%40%
2520
21st to endDay
7%5%25%5%47%6%8%12%39%
2520
July1st to 10thDay
8%4245%36%8%8%12%38%
2520
11th to 20thDay
8%5%35%5%46%8%9%12%36%
2406
21st to endDay
7%425%6%5%8%7%8%12%36%
2547
August1st to 10thDay
10%5%26%7%46%8%8%10%33%
2297
11th to 20thDay
11%6%37%7%46%7%7%10%33%
2126
21st to endDay
12%6%25%5%45%7%8%10%35%
2376
September1st to 10thDay
14%5%25%5%45%5%6%10%39%
2160
11th to 20thDay
14%7%26%5%35%45%8%40%
2160
21st to endDay
20%6%35%5%45%5%47%36%
1936
October1st to 10thDay
17%6%34435%45%6%44%
1800
11th to 20thDay
15%6%25%5%3445%5%47%
1800
21st to endDay
13%5%25%433446%49%
1980
November1st to 10thDay
16%5%34424446%49%
1758
11th to 20thDay
15%7%3442345%6%48%
1710
21st to endDay
14%425%5%3445%6%49%
1676
December1st to 10thDay
16%6%36%5%2446%6%41%
1520
11th to 20thDay
15%6%245%24345%50%
1910
21st to endDay
16%6%25%42435%8%44%
2772
January1st to 10thNight
14%7%35%43445%6%45%
2564
11th to 20thNight
16%6%36%6%35%45%7%39%
2378
21st to endNight
17%6%25%433446%47%
2574
February1st to 10thNight
17%8%25%4245%5%6%42%
2340
11th to 20thNight
21%7%35%433346%41%
2116
21st to endNight
15%7%35%434446%45%
1776
March1st to 10thNight
14%5%245%2445%6%50%
2062
11th to 20thNight
18%6%35%5%35%5%5%7%39%
1980
21st to endNight
17%6%25%6%36%346%42%
2105
April1st to 10thNight
13%6%25%5%35%5%6%7%44%
1800
11th to 20thNight
13%6%245%2336%7%50%
1775
21st to endNight
14%6%2443445%7%45%
1800
May1st to 10thNight
14%6%35%5%35%5%5%10%39%
1800
11th to 20thNight
14%6%25%5%3446%9%40%
1546
21st to endNight
12%5%25%5%45%6%5%10%43%
1550
June1st to 10thNight
11%5%345%45%5%7%10%41%
1440
11th to 20thNight
7%426%6%5%6%7%6%10%41%
1440
21st to endNight
7%5%25%7%35%6%7%11%43%
1440
July1st to 10thNight
7%5%36%6%45%5%7%13%41%
1440
11th to 20thNight
7%4245%36%6%7%10%44%
1550
21st to endNight
8%5%36%6%46%7%9%11%38%
1771
August1st to 10thNight
7%6%37%7%45%6%6%12%37%
1624
11th to 20thNight
9%6%36%6%5%5%6%7%10%37%
1774
21st to endNight
10%7%36%6%45%7%6%10%38%
1980
September1st to 10thNight
10%6%36%5%345%5%9%44%
1800
11th to 20thNight
12%6%26%6%35%447%45%
1800
21st to endNight
17%7%37%6%35%45%7%36%
2019
October1st to 10thNight
15%5%25%425%5%45%47%
2160
11th to 20thNight
15%6%345%2345%6%49%
2160
21st to endNight
13%5%2443345%6%50%
2376
November1st to 10thNight
15%6%35%434446%47%
2320
11th to 20thNight
14%7%26%42345%7%46%
2470
21st to endNight
13%4245%3445%7%50%
2501
December1st to 10thNight
15%8%36%6%34446%40%
2660
11th to 20thNight
17%6%24434347%45%
3285
21st to endNight
13%6%35%4345%5%7%45%
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
39%6%11%25%16%4
1598
11th to 20thDay
42%5%10%22%17%3
1644
21st to endDay
40%410%24%19%3
1782
February1st to 10thDay
43%5%12%24%12%3
1620
11th to 20thDay
43%410%18%19%5%
1739
21st to endDay
43%7%11%19%14%6%
1480
March1st to 10thDay
36%412%24%20%4
1894
11th to 20thDay
41%6%11%20%17%5%
1980
21st to endDay
41%7%13%19%18%3
2250
April1st to 10thDay
33%6%13%22%21%5%
2160
11th to 20thDay
33%6%12%24%20%5%
2134
21st to endDay
37%6%13%22%17%4
2160
May1st to 10thDay
38%8%15%22%14%3
2160
11th to 20thDay
43%7%14%24%10%2
2363
21st to endDay
38%9%16%25%12%1
2725
June1st to 10thDay
34%10%17%25%13%1
2520
11th to 20thDay
36%10%17%22%14%1
2520
21st to endDay
35%11%17%23%13%1
2520
July1st to 10thDay
33%13%17%23%12%2
2450
11th to 20thDay
35%12%21%23%9%1
2333
21st to endDay
36%12%18%21%12%1
2405
August1st to 10thDay
41%12%19%21%7%
2284
11th to 20thDay
43%10%15%21%10%1
2126
21st to endDay
40%11%17%18%12%3
2376
September1st to 10thDay
39%10%16%17%15%3
2160
11th to 20thDay
42%6%12%21%17%2
2160
21st to endDay
47%8%9%20%14%2
1936
October1st to 10thDay
40%6%10%22%19%3
1800
11th to 20thDay
39%5%9%25%19%4
1800
21st to endDay
35%6%8%23%23%5%
1980
November1st to 10thDay
38%5%11%24%19%3
1758
11th to 20thDay
36%5%13%20%20%5%
1710
21st to endDay
36%5%9%27%20%3
1676
December1st to 10thDay
42%6%13%21%15%3
1520
11th to 20thDay
37%5%9%26%17%6%
1906
21st to endDay
39%5%10%28%16%2
2772
January1st to 10thNight
39%6%10%23%17%5%
2564
11th to 20thNight
45%7%11%19%15%3
2378
21st to endNight
40%39%23%20%5%
2574
February1st to 10thNight
42%6%9%23%16%3
2340
11th to 20thNight
45%48%22%15%5%
2118
21st to endNight
41%5%9%21%18%7%
1776
March1st to 10thNight
37%5%11%24%20%4
2062
11th to 20thNight
44%7%11%19%16%3
1980
21st to endNight
43%6%10%21%16%4
2105
April1st to 10thNight
39%7%12%17%21%4
1800
11th to 20thNight
34%6%11%23%20%6%
1775
21st to endNight
37%7%12%23%17%4
1800
May1st to 10thNight
39%9%13%23%13%3
1800
11th to 20thNight
40%9%16%21%12%2
1547
21st to endNight
36%10%17%23%12%2
1551
June1st to 10thNight
36%7%17%25%13%1
1440
11th to 20thNight
36%12%19%19%13%1
1440
21st to endNight
34%10%18%23%13%2
1440
July1st to 10thNight
35%12%17%23%11%3
1400
11th to 20thNight
30%12%21%25%11%1
1500
21st to endNight
34%14%17%25%10%1
1672
August1st to 10thNight
39%11%22%22%7%
1613
11th to 20thNight
40%11%17%21%10%
1774
21st to endNight
41%11%15%21%11%2
1980
September1st to 10thNight
36%9%18%21%14%3
1800
11th to 20thNight
40%6%11%22%18%2
1800
21st to endNight
46%8%11%18%15%2
2019
October1st to 10thNight
37%7%9%23%21%3
2160
11th to 20thNight
36%6%9%23%22%4
2160
21st to endNight
35%6%9%23%22%6%
2376
November1st to 10thNight
38%6%10%21%22%3
2320
11th to 20thNight
38%6%10%19%19%7%
2470
21st to endNight
34%6%10%25%22%4
2501
December1st to 10thNight
45%6%10%20%14%3
2660
11th to 20thNight
39%6%10%21%19%5%
3288
21st to endNight
37%7%14%24%16%2
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
17%21%38%18%6%
218
11th to 20thDay
19%20%38%20%3
248
21st to endDay
21%14%39%22%41
264
February1st to 10thDay
20%15%40%19%5%
240
11th to 20thDay
26%17%38%15%4
398
21st to endDay
20%18%38%21%31
346
March1st to 10thDay
17%17%40%20%5%1
420
11th to 20thDay
20%19%33%20%5%2
420
21st to endDay
16%14%38%25%7%1
462
April1st to 10thDay
16%17%35%23%6%1
420
11th to 20thDay
12%11%32%30%12%3
412
21st to endDay
19%10%33%25%11%2
420
May1st to 10thDay
17%11%33%26%11%2
423
11th to 20thDay
20%5%26%32%14%3
447
21st to endDay
19%418%29%22%7%
485
June1st to 10thDay
13%419%32%26%6%
450
11th to 20thDay
15%7%16%30%23%9%
450
21st to endDay
9%219%38%26%6%
450
July1st to 10thDay
10%19%35%35%11%
445
11th to 20thDay
8%36%29%40%14%
444
21st to endDay
8%216%32%32%9%
488
August1st to 10thDay
13%213%35%29%9%
446
11th to 20thDay
10%210%29%33%15%
439
21st to endDay
13%212%28%32%13%
495
September1st to 10thDay
14%317%28%23%15%
450
11th to 20thDay
17%413%31%26%9%
450
21st to endDay
24%6%18%24%22%5%
450
October1st to 10thDay
21%5%18%25%22%8%
450
11th to 20thDay
18%9%23%26%20%3
450
21st to endDay
17%8%31%26%14%4
495
November1st to 10thDay
18%9%27%26%14%5%
408
11th to 20thDay
18%12%32%26%9%3
370
21st to endDay
15%16%28%26%14%2
336
December1st to 10thDay
22%15%39%16%6%2
180
11th to 20thDay
16%17%37%21%9%1
180
21st to endDay
24%13%28%22%12%2
198
January1st to 10thNight
18%16%36%24%6%
760
11th to 20thNight
21%14%31%27%7%
732
21st to endNight
19%13%41%24%3
792
February1st to 10thNight
21%11%38%26%4
720
11th to 20thNight
24%16%39%19%2
703
21st to endNight
20%14%37%24%5%
592
March1st to 10thNight
18%10%38%28%6%
720
11th to 20thNight
20%10%38%24%7%1
720
21st to endNight
20%11%33%29%6%
792
April1st to 10thNight
18%10%39%26%7%
720
11th to 20thNight
14%10%32%32%11%
711
21st to endNight
18%5%31%38%8%1
720
May1st to 10thNight
17%8%32%33%9%1
720
11th to 20thNight
15%425%41%14%1
485
21st to endNight
15%412%41%24%3
389
June1st to 10thNight
12%317%42%22%4
360
11th to 20thNight
8%216%43%28%3
360
21st to endNight
9%113%48%27%2
360
July1st to 10thNight
8%210%41%36%2
350
11th to 20thNight
6%8%39%41%6%
456
21st to endNight
9%213%43%30%4
591
August1st to 10thNight
9%29%42%33%5%
550
11th to 20thNight
12%112%36%34%6%
710
21st to endNight
12%212%31%36%7%
792
September1st to 10thNight
13%211%35%30%9%
720
11th to 20thNight
16%213%34%29%6%
720
21st to endNight
21%415%33%24%2
720
October1st to 10thNight
18%417%31%26%5%
720
11th to 20thNight
18%7%22%33%18%2
720
21st to endNight
16%8%25%31%17%3
792
November1st to 10thNight
18%7%25%30%16%3
740
11th to 20thNight
18%11%31%27%13%1
760
21st to endNight
14%11%28%31%15%1
760
December1st to 10thNight
19%13%32%26%9%
760
11th to 20thNight
17%9%36%29%8%
760
21st to endNight
19%9%31%33%7%
836
Page generated at 2024-01-10 19:35:23. Version ac07

Copyright 2024 Attilla Danko


Renaissance Academy Clear Sky Chart |Charts Home