The Loose Rooster Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Loose Rooster Observatory clear sky chart from 2005-11-06 to 2024-01-12.

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
28%
23051
16%
74710
8%
23009
37%
23009
17%
51321

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
11%
760
15%
2649
4%
757
24%
757
9%
1919
January11th to 20thNight
17%
727
12%
2527
5%
727
27%
727
11%
1869
January21st to endNight
12%
792
15%
2574
5%
792
24%
792
11%
1892
February1st to 10thNight
11%
720
13%
2340
4%
720
24%
720
12%
1707
February11th to 20thNight
9%
703
12%
2188
2%
700
21%
700
9%
1625
February21st to endNight
12%
592
18%
1776
5%
592
29%
592
12%
1298
March1st to 10thNight
16%
720
16%
2142
6%
720
28%
720
14%
1537
March11th to 20thNight
17%
720
17%
1980
6%
720
29%
720
17%
1402
March21st to endNight
18%
792
19%
2066
6%
792
29%
792
17%
1483
April1st to 10thNight
18%
720
14%
1800
2%
720
25%
720
16%
1348
April11th to 20thNight
22%
711
16%
1775
5%
711
28%
711
22%
1265
April21st to endNight
25%
720
16%
1800
4%
720
31%
720
20%
1284
May1st to 10thNight
29%
492
15%
1572
9%
492
34%
492
16%
1122
May11th to 20thNight
29%
354
20%
1416
11%
354
44%
354
17%
911
May21st to endNight
43%
388
14%
1551
14%
388
49%
388
19%
957
June1st to 10thNight
45%
360
17%
1440
16%
360
55%
360
20%
880
June11th to 20thNight
44%
360
15%
1440
15%
360
53%
360
21%
876
June21st to endNight
51%
360
16%
1440
17%
360
59%
360
25%
828
July1st to 10thNight
55%
350
14%
1400
17%
350
60%
350
23%
841
July11th to 20thNight
56%
348
17%
1392
21%
348
60%
348
23%
798
July21st to endNight
53%
399
17%
1491
17%
377
58%
377
23%
869
August1st to 10thNight
57%
537
16%
1600
12%
534
60%
534
30%
1002
August11th to 20thNight
55%
635
15%
1699
10%
635
56%
635
27%
1153
August21st to endNight
53%
792
19%
1980
10%
792
55%
792
31%
1322
September1st to 10thNight
47%
720
19%
1800
9%
720
51%
720
29%
1231
September11th to 20thNight
49%
720
27%
1808
17%
720
54%
720
35%
1150
September21st to endNight
42%
720
24%
2010
17%
720
49%
720
27%
1312
October1st to 10thNight
40%
720
17%
2160
14%
720
46%
720
23%
1405
October11th to 20thNight
33%
720
18%
2160
10%
720
44%
720
23%
1426
October21st to endNight
25%
792
17%
2448
9%
792
36%
792
18%
1700
November1st to 10thNight
28%
740
21%
2407
11%
740
41%
740
21%
1522
November11th to 20thNight
23%
760
20%
2484
10%
760
36%
760
16%
1694
November21st to endNight
20%
760
16%
2660
6%
760
35%
760
15%
1793
December1st to 10thNight
15%
760
11%
2660
5%
760
23%
760
9%
1983
December11th to 20thNight
17%
760
12%
3235
5%
759
26%
759
8%
2339
December21st to endNight
13%
827
8%
4840
4%
817
24%
817
6%
3578

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
15%9%47%6%45%5%5%7%33%
74723
Night
15%9%47%6%35%45%7%35%
74979
TransparencyDay
50%5%11%21%11%1
74429
Night
49%5%12%21%11%1
74807
SeeingDay
25%17%28%18%9%3
13701
Night
22%16%28%24%9%1
23061

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
13%10%8%11%7%45%5%45%29%
1517
11th to 20thDay
14%13%6%12%8%46%446%22%
1457
21st to endDay
12%11%6%11%9%45%45%6%27%
1782
February1st to 10thDay
16%11%5%9%9%5%6%45%6%23%
1620
11th to 20thDay
14%12%5%8%7%45%45%8%29%
1659
21st to endDay
18%12%39%7%345%46%28%
1480
March1st to 10thDay
14%10%6%9%6%45%447%32%
1811
11th to 20thDay
15%11%5%8%7%45%447%30%
1980
21st to endDay
19%10%48%6%35%446%32%
2290
April1st to 10thDay
17%11%46%6%35%446%34%
2160
11th to 20thDay
15%11%36%5%3445%6%36%
2134
21st to endDay
17%9%46%6%345%6%6%34%
2160
May1st to 10thDay
20%9%37%6%35%5%5%7%31%
2402
11th to 20thDay
19%7%36%6%45%46%6%33%
2478
21st to endDay
15%7%26%6%35%6%5%8%37%
2725
June1st to 10thDay
16%6%37%6%45%6%5%9%33%
2520
11th to 20thDay
15%8%36%6%46%6%6%8%32%
2520
21st to endDay
13%6%26%6%45%5%7%9%36%
2520
July1st to 10thDay
12%6%26%7%46%6%7%10%35%
2520
11th to 20thDay
9%5%36%6%36%6%7%11%38%
2520
21st to endDay
11%6%36%6%46%6%6%8%37%
2736
August1st to 10thDay
12%7%35%6%47%7%8%9%33%
2327
11th to 20thDay
13%7%37%7%5%5%5%5%8%34%
2183
21st to endDay
14%8%36%6%35%5%6%8%36%
2376
September1st to 10thDay
17%6%36%6%345%5%8%37%
2160
11th to 20thDay
13%6%35%5%35%447%45%
2151
21st to endDay
16%7%36%5%35%5%6%7%37%
1947
October1st to 10thDay
18%8%26%5%35%5%5%7%36%
1800
11th to 20thDay
16%8%46%6%45%45%8%36%
1800
21st to endDay
22%10%46%5%45%45%7%29%
1908
November1st to 10thDay
14%10%36%5%24347%42%
1671
11th to 20thDay
15%12%47%6%24446%34%
1691
21st to endDay
18%11%47%6%345%5%6%31%
1520
December1st to 10thDay
18%13%6%8%7%3445%7%26%
1520
11th to 20thDay
19%13%6%9%5%33446%28%
1906
21st to endDay
19%17%8%9%6%35%45%5%19%
2772
January1st to 10thNight
13%11%6%11%8%35%45%6%27%
2649
11th to 20thNight
15%12%5%9%7%36%5%5%6%26%
2527
21st to endNight
10%11%5%9%9%46%6%5%6%28%
2574
February1st to 10thNight
17%11%5%8%7%35%45%6%30%
2340
11th to 20thNight
14%11%5%9%7%46%5%5%6%27%
2186
21st to endNight
17%11%49%6%35%44431%
1776
March1st to 10thNight
16%10%5%9%5%345%5%7%31%
2132
11th to 20thNight
14%11%47%7%3445%7%34%
1979
21st to endNight
16%11%46%6%35%45%5%36%
2066
April1st to 10thNight
16%12%5%7%7%44446%31%
1800
11th to 20thNight
17%8%36%6%345%47%38%
1775
21st to endNight
19%8%35%5%3445%5%38%
1800
May1st to 10thNight
21%10%36%5%35%35%5%32%
1572
11th to 20thNight
14%7%36%6%37%45%8%37%
1415
21st to endNight
11%7%47%6%35%6%6%8%38%
1550
June1st to 10thNight
16%6%35%435%5%6%8%39%
1440
11th to 20thNight
13%7%36%5%335%6%8%39%
1440
21st to endNight
12%415%435%5%6%9%46%
1440
July1st to 10thNight
12%6%35%5%45%6%5%8%42%
1440
11th to 20thNight
10%5%35%5%35%5%7%10%42%
1440
21st to endNight
11%6%345%45%5%6%9%43%
1579
August1st to 10thNight
11%5%26%5%35%7%6%10%40%
1611
11th to 20thNight
12%7%36%6%45%6%7%7%38%
1699
21st to endNight
12%5%36%5%35%45%8%44%
1980
September1st to 10thNight
15%6%35%5%35%5%5%7%42%
1800
11th to 20thNight
13%6%2442445%6%49%
1808
21st to endNight
15%7%26%5%335%6%7%41%
2010
October1st to 10thNight
19%7%3433445%6%41%
2160
11th to 20thNight
16%8%35%5%4445%5%41%
2160
21st to endNight
22%10%35%425%46%7%33%
2448
November1st to 10thNight
12%9%46%5%34346%43%
2407
11th to 20thNight
17%10%47%5%3445%6%35%
2484
21st to endNight
13%11%46%5%35%46%6%35%
2660
December1st to 10thNight
18%12%5%8%6%35%5%6%6%25%
2660
11th to 20thNight
17%14%5%8%6%35%446%28%
3288
21st to endNight
21%15%7%8%5%34445%24%
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
57%49%21%8%1
1518
11th to 20thDay
63%5%10%13%7%2
1457
21st to endDay
58%410%18%9%1
1782
February1st to 10thDay
61%5%11%14%9%1
1620
11th to 20thDay
55%5%9%21%10%1
1668
21st to endDay
58%49%20%7%2
1480
March1st to 10thDay
53%412%20%9%2
1814
11th to 20thDay
54%48%21%12%1
1980
21st to endDay
55%47%17%14%2
2290
April1st to 10thDay
53%48%21%10%3
2160
11th to 20thDay
48%5%10%23%13%2
2134
21st to endDay
49%49%22%12%4
2160
May1st to 10thDay
54%5%8%19%12%3
2402
11th to 20thDay
51%6%9%20%12%2
2482
21st to endDay
44%6%15%20%12%2
2725
June1st to 10thDay
48%5%13%21%12%1
2520
11th to 20thDay
49%5%13%21%10%1
2520
21st to endDay
44%6%13%26%11%
2520
July1st to 10thDay
45%6%13%22%13%1
2450
11th to 20thDay
37%6%16%26%14%1
2445
21st to endDay
43%6%13%21%15%2
2583
August1st to 10thDay
45%6%14%23%11%
2314
11th to 20thDay
47%6%14%23%10%
2183
21st to endDay
46%411%23%14%2
2376
September1st to 10thDay
46%5%12%21%14%1
2160
11th to 20thDay
39%411%22%21%2
2151
21st to endDay
45%5%10%23%16%2
1947
October1st to 10thDay
46%5%12%22%13%2
1800
11th to 20thDay
47%5%11%24%13%1
1800
21st to endDay
55%412%18%9%2
1908
November1st to 10thDay
44%412%24%14%3
1671
11th to 20thDay
51%410%21%13%2
1691
21st to endDay
53%414%21%7%1
1520
December1st to 10thDay
58%5%16%13%7%1
1520
11th to 20thDay
59%415%17%5%
1906
21st to endDay
68%410%13%5%
2772
January1st to 10thNight
56%5%10%19%8%2
2649
11th to 20thNight
58%5%13%17%6%1
2527
21st to endNight
55%6%10%18%10%1
2574
February1st to 10thNight
55%5%12%19%9%1
2340
11th to 20thNight
57%5%11%17%9%1
2188
21st to endNight
56%47%20%11%2
1776
March1st to 10thNight
53%411%19%11%2
2142
11th to 20thNight
50%412%21%11%1
1980
21st to endNight
51%49%17%17%3
2066
April1st to 10thNight
55%49%19%12%2
1800
11th to 20thNight
46%5%11%21%16%1
1775
21st to endNight
48%5%10%21%14%3
1800
May1st to 10thNight
54%49%20%10%3
1572
11th to 20thNight
44%7%10%22%15%2
1416
21st to endNight
42%7%16%22%11%2
1551
June1st to 10thNight
43%5%11%26%14%
1440
11th to 20thNight
41%6%16%26%10%1
1440
21st to endNight
36%6%15%29%13%
1440
July1st to 10thNight
39%7%15%24%14%2
1400
11th to 20thNight
36%8%17%28%11%1
1392
21st to endNight
36%8%17%22%15%2
1491
August1st to 10thNight
38%6%16%28%12%1
1600
11th to 20thNight
42%7%16%22%12%
1699
21st to endNight
39%6%12%24%18%1
1980
September1st to 10thNight
41%6%13%24%15%1
1800
11th to 20thNight
36%410%26%22%2
1808
21st to endNight
41%49%25%18%1
2010
October1st to 10thNight
44%412%24%15%1
2160
11th to 20thNight
44%5%14%25%11%1
2160
21st to endNight
50%5%13%21%11%1
2448
November1st to 10thNight
43%412%22%17%3
2407
11th to 20thNight
49%411%21%12%3
2484
21st to endNight
48%5%14%23%9%1
2660
December1st to 10thNight
59%6%11%18%6%
2660
11th to 20thNight
57%6%12%17%8%1
3288
21st to endNight
63%411%18%4
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
34%25%28%9%21
180
11th to 20thDay
42%25%25%7%2
166
21st to endDay
31%30%28%7%31
264
February1st to 10thDay
39%30%25%6%
240
11th to 20thDay
36%28%30%6%1
326
21st to endDay
35%29%25%8%3
346
March1st to 10thDay
31%24%31%11%2
420
11th to 20thDay
31%25%26%13%41
420
21st to endDay
35%23%25%10%42
462
April1st to 10thDay
32%24%26%12%5%
420
11th to 20thDay
28%22%29%12%7%2
412
21st to endDay
28%24%30%12%42
420
May1st to 10thDay
35%18%28%9%7%3
423
11th to 20thDay
25%17%33%15%7%2
447
21st to endDay
19%12%29%24%12%3
485
June1st to 10thDay
20%15%29%23%10%3
450
11th to 20thDay
20%17%25%24%13%1
450
21st to endDay
18%12%33%27%8%1
450
July1st to 10thDay
16%7%27%28%17%5%
445
11th to 20thDay
9%7%31%32%17%4
444
21st to endDay
14%10%34%28%9%4
488
August1st to 10thDay
13%8%27%26%19%7%
446
11th to 20thDay
15%8%26%29%16%6%
439
21st to endDay
13%11%28%25%15%7%
495
September1st to 10thDay
20%12%21%21%18%8%
450
11th to 20thDay
15%9%27%21%17%11%
450
21st to endDay
24%12%26%21%13%4
450
October1st to 10thDay
26%13%23%19%13%6%
450
11th to 20thDay
23%17%30%21%8%1
450
21st to endDay
30%18%30%16%6%1
459
November1st to 10thDay
24%20%22%23%9%1
365
11th to 20thDay
32%22%28%15%41
351
21st to endDay
38%21%31%9%2
180
December1st to 10thDay
36%26%26%8%31
180
11th to 20thDay
39%23%27%8%2
180
21st to endDay
31%29%28%10%21
198
January1st to 10thNight
24%26%34%12%3
760
11th to 20thNight
27%22%30%18%3
727
21st to endNight
20%28%34%15%2
792
February1st to 10thNight
30%22%32%15%1
720
11th to 20thNight
29%28%31%11%1
703
21st to endNight
29%26%31%14%2
592
March1st to 10thNight
28%23%30%16%3
720
11th to 20thNight
28%21%31%16%4
720
21st to endNight
25%21%32%16%6%
792
April1st to 10thNight
24%23%30%20%2
720
11th to 20thNight
24%20%30%19%7%
711
21st to endNight
27%17%27%25%5%
720
May1st to 10thNight
28%12%27%24%9%
492
11th to 20thNight
17%10%36%29%6%1
354
21st to endNight
13%9%26%37%15%
389
June1st to 10thNight
16%8%23%38%14%
360
11th to 20thNight
14%9%27%39%11%
360
21st to endNight
13%5%25%47%9%1
360
July1st to 10thNight
13%5%21%38%22%1
350
11th to 20thNight
12%5%19%44%18%2
348
21st to endNight
14%7%19%42%17%1
399
August1st to 10thNight
12%320%44%18%3
537
11th to 20thNight
16%315%36%28%2
635
21st to endNight
16%5%18%36%24%1
792
September1st to 10thNight
17%6%22%35%17%3
720
11th to 20thNight
16%7%21%30%21%6%
720
21st to endNight
20%9%22%29%18%3
720
October1st to 10thNight
24%9%22%26%17%1
720
11th to 20thNight
19%15%29%30%8%
720
21st to endNight
28%15%29%22%6%
792
November1st to 10thNight
18%18%31%24%7%1
740
11th to 20thNight
25%21%28%19%6%1
760
21st to endNight
23%22%31%19%5%1
760
December1st to 10thNight
29%21%30%15%4
760
11th to 20thNight
26%25%28%18%3
760
21st to endNight
28%22%33%16%2
836
Page generated at 2024-01-09 07:14:42. Version ac07

Copyright 2024 Attilla Danko


The Loose Rooster Observatory Clear Sky Chart |Charts Home