Eyegloo Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eyegloo Observatory clear sky chart from 2005-11-06 to 2024-01-27.

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
46%
23865
25%
74470
17%
23806
55%
23806
32%
43093

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
35%
949
30%
2458
12%
946
46%
946
37%
1479
January11th to 20thNight
34%
950
27%
2470
11%
950
43%
950
31%
1542
January21st to endNight
30%
953
29%
2593
11%
953
43%
953
30%
1640
February1st to 10thNight
28%
720
27%
2160
10%
720
42%
720
26%
1328
February11th to 20thNight
25%
704
23%
2098
8%
700
37%
700
26%
1284
February21st to endNight
18%
592
27%
1776
6%
592
35%
592
23%
1113
March1st to 10thNight
26%
552
24%
1992
10%
552
42%
552
22%
1208
March11th to 20thNight
31%
540
22%
1980
14%
540
41%
540
21%
1205
March21st to endNight
26%
594
25%
2178
13%
594
43%
594
25%
1236
April1st to 10thNight
28%
540
23%
1980
13%
540
43%
540
24%
1159
April11th to 20thNight
26%
533
21%
1953
13%
533
41%
533
23%
1181
April21st to endNight
28%
540
28%
1647
13%
540
46%
540
30%
1001
May1st to 10thNight
32%
540
24%
1620
16%
540
45%
540
28%
1003
May11th to 20thNight
44%
531
22%
1594
20%
531
51%
531
31%
981
May21st to endNight
45%
583
22%
1745
15%
582
56%
582
31%
1069
June1st to 10thNight
63%
540
24%
1620
21%
540
72%
540
46%
835
June11th to 20thNight
58%
540
23%
1620
22%
540
66%
540
47%
841
June21st to endNight
66%
540
23%
1620
25%
540
70%
540
39%
926
July1st to 10thNight
68%
525
18%
1575
19%
525
71%
525
35%
915
July11th to 20thNight
80%
522
27%
1566
29%
522
84%
522
52%
761
July21st to endNight
80%
591
27%
1673
28%
558
85%
558
51%
827
August1st to 10thNight
86%
537
31%
1601
33%
534
89%
534
64%
707
August11th to 20thNight
77%
534
25%
1720
27%
534
80%
534
38%
929
August21st to endNight
78%
594
21%
2086
24%
594
80%
594
34%
1125
September1st to 10thNight
71%
540
22%
1980
25%
540
74%
540
33%
1072
September11th to 20thNight
67%
540
21%
1980
23%
540
69%
540
28%
1156
September21st to endNight
69%
540
27%
1980
27%
540
73%
540
35%
1025
October1st to 10thNight
72%
540
34%
1980
34%
540
75%
540
41%
946
October11th to 20thNight
53%
666
32%
2106
21%
666
62%
666
36%
1181
October21st to endNight
47%
792
32%
2376
19%
792
55%
792
37%
1331
November1st to 10thNight
53%
740
29%
2220
19%
740
59%
740
35%
1298
November11th to 20thNight
47%
874
27%
2394
14%
874
54%
874
37%
1417
November21st to endNight
37%
950
27%
2470
12%
950
45%
950
29%
1626
December1st to 10thNight
38%
950
30%
2470
14%
950
47%
950
34%
1554
December11th to 20thNight
33%
948
25%
2881
11%
948
40%
948
25%
1841
December21st to endNight
36%
1041
17%
4308
12%
1026
44%
1026
23%
2351

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
12%5%2443445%7%48%
75017
Night
12%5%2442345%7%53%
75056
TransparencyDay
35%6%10%20%20%9%
74742
Night
33%5%11%20%20%12%
74851
SeeingDay
13%8%22%30%22%5%
13800
Night
15%8%27%35%14%1
23873

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%5%24423346%54%
1707
11th to 20thDay
18%5%23422336%51%
1710
21st to endDay
16%6%23423335%51%
1922
February1st to 10thDay
20%7%34323336%47%
1800
11th to 20thDay
18%6%34433446%46%
1749
21st to endDay
20%5%24323335%50%
1480
March1st to 10thDay
20%7%45%5%23446%42%
1966
11th to 20thDay
16%7%35%5%2445%5%46%
1980
21st to endDay
14%5%3442345%6%50%
2178
April1st to 10thDay
15%7%35%5%2445%7%43%
1980
11th to 20thDay
17%6%35%424445%45%
1956
21st to endDay
14%5%345%3435%6%47%
2306
May1st to 10thDay
14%6%36%5%35%5%5%7%41%
2340
11th to 20thDay
15%7%26%5%45%5%5%7%40%
2302
21st to endDay
16%5%36%6%45%6%6%9%34%
2531
June1st to 10thDay
6%325%5%45%6%6%8%51%
2340
11th to 20thDay
7%414435%5%7%10%50%
2340
21st to endDay
7%435%5%45%7%8%10%40%
2340
July1st to 10thDay
9%5%35%7%36%6%7%9%40%
2340
11th to 20thDay
5%313435%5%7%11%53%
2340
21st to endDay
5%223335%5%7%12%52%
2546
August1st to 10thDay
221222445%9%66%
2328
11th to 20thDay
6%324435%5%7%9%52%
2175
21st to endDay
5%325%5%36%7%7%10%46%
2268
September1st to 10thDay
8%435%6%35%5%6%8%47%
1980
11th to 20thDay
11%5%26%5%445%6%8%43%
1980
21st to endDay
7%424435%5%6%8%52%
1980
October1st to 10thDay
7%324434447%58%
1980
11th to 20thDay
13%424423436%54%
1836
21st to endDay
12%424323345%60%
1980
November1st to 10thDay
15%6%23434346%49%
1858
11th to 20thDay
11%4245%3445%6%52%
1783
21st to endDay
17%6%35%5%24445%47%
1710
December1st to 10thDay
14%7%24423446%50%
1710
11th to 20thDay
16%7%35%43445%5%45%
2161
21st to endDay
16%5%24312335%55%
3135
January1st to 10thNight
16%5%13213336%56%
2458
11th to 20thNight
16%5%24323346%52%
2470
21st to endNight
17%5%345%23345%50%
2593
February1st to 10thNight
18%7%34322235%51%
2160
11th to 20thNight
19%5%34323245%50%
2098
21st to endNight
21%5%24424335%48%
1776
March1st to 10thNight
17%7%2442445%7%44%
1992
11th to 20thNight
16%7%35%424445%45%
1980
21st to endNight
14%6%34323447%51%
2178
April1st to 10thNight
13%6%2442445%7%48%
1980
11th to 20thNight
18%7%2442445%6%45%
1953
21st to endNight
14%6%25%424346%50%
1647
May1st to 10thNight
12%5%344345%6%9%45%
1620
11th to 20thNight
11%6%25%42445%8%48%
1593
21st to endNight
12%6%24425%6%6%9%46%
1745
June1st to 10thNight
43133335%6%10%58%
1620
11th to 20thNight
5%2123245%6%9%59%
1620
21st to endNight
6%4245%245%7%9%53%
1620
July1st to 10thNight
7%4244346%6%11%50%
1620
11th to 20thNight
321231347%10%64%
1620
21st to endNight
32132335%5%12%60%
1772
August1st to 10thNight
11221236%10%72%
1611
11th to 20thNight
6%3243235%6%10%55%
1720
21st to endNight
5%3246%345%7%11%51%
2086
September1st to 10thNight
7%5%244246%6%8%51%
1980
11th to 20thNight
11%5%25%6%3446%9%46%
1980
21st to endNight
9%32343445%8%56%
1980
October1st to 10thNight
7%31342335%6%63%
1980
11th to 20thNight
13%5%1332335%7%55%
2106
21st to endNight
15%42332333459%
2376
November1st to 10thNight
14%5%14423336%55%
2220
11th to 20thNight
10%424434346%57%
2394
21st to endNight
18%6%24424336%48%
2470
December1st to 10thNight
13%6%24423346%53%
2470
11th to 20thNight
15%9%35%42344448%
3036
21st to endNight
19%6%2321233455%
4532

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
33%46%20%23%14%
1708
11th to 20thDay
37%36%17%24%13%
1710
21st to endDay
37%36%14%25%15%
1922
February1st to 10thDay
41%46%12%22%15%
1800
11th to 20thDay
41%48%17%19%12%
1759
21st to endDay
39%45%16%19%16%
1480
March1st to 10thDay
46%47%13%20%10%
1966
11th to 20thDay
41%6%6%12%21%14%
1980
21st to endDay
36%5%10%17%21%11%
2178
April1st to 10thDay
42%48%18%15%12%
1980
11th to 20thDay
42%5%7%16%19%11%
1956
21st to endDay
38%5%5%21%22%9%
2306
May1st to 10thDay
42%6%9%16%19%8%
2340
11th to 20thDay
44%7%9%19%18%4
2306
21st to endDay
44%9%12%19%14%2
2531
June1st to 10thDay
29%7%13%27%19%4
2340
11th to 20thDay
29%8%13%27%17%6%
2340
21st to endDay
35%9%14%21%18%3
2340
July1st to 10thDay
39%8%16%24%12%1
2276
11th to 20thDay
24%8%17%26%23%2
2271
21st to endDay
21%10%20%34%14%1
2405
August1st to 10thDay
16%6%16%38%22%2
2314
11th to 20thDay
27%8%16%30%14%5%
2175
21st to endDay
29%10%16%26%15%4
2268
September1st to 10thDay
35%7%11%22%16%9%
1980
11th to 20thDay
39%8%13%18%17%6%
1980
21st to endDay
29%7%10%20%21%13%
1980
October1st to 10thDay
27%6%10%21%23%13%
1980
11th to 20thDay
33%48%16%22%18%
1836
21st to endDay
29%46%14%26%21%
1980
November1st to 10thDay
36%6%9%17%21%10%
1858
11th to 20thDay
35%5%7%18%21%15%
1783
21st to endDay
41%46%15%21%14%
1710
December1st to 10thDay
37%310%18%23%9%
1710
11th to 20thDay
41%5%6%12%23%12%
2159
21st to endDay
34%36%14%28%14%
3135
January1st to 10thNight
33%25%17%25%18%
2458
11th to 20thNight
36%36%16%24%15%
2470
21st to endNight
38%3415%21%18%
2593
February1st to 10thNight
39%46%12%21%18%
2160
11th to 20thNight
39%36%16%20%15%
2098
21st to endNight
41%46%14%17%18%
1776
March1st to 10thNight
41%5%9%14%21%10%
1992
11th to 20thNight
41%5%9%11%20%14%
1980
21st to endNight
36%5%10%16%20%13%
2178
April1st to 10thNight
37%6%8%18%17%14%
1980
11th to 20thNight
40%5%9%13%18%15%
1953
21st to endNight
37%410%20%20%9%
1647
May1st to 10thNight
36%7%10%20%18%9%
1620
11th to 20thNight
35%7%11%26%17%4
1594
21st to endNight
34%7%15%28%14%2
1746
June1st to 10thNight
21%6%17%29%23%4
1620
11th to 20thNight
22%6%17%30%20%6%
1620
21st to endNight
27%7%16%27%18%4
1620
July1st to 10thNight
28%10%21%29%12%1
1575
11th to 20thNight
15%8%23%32%22%1
1566
21st to endNight
17%7%25%39%12%
1673
August1st to 10thNight
10%6%22%39%22%2
1601
11th to 20thNight
25%8%21%29%13%4
1720
21st to endNight
26%9%19%28%13%4
2086
September1st to 10thNight
29%7%15%25%17%7%
1980
11th to 20thNight
35%6%16%22%14%6%
1980
21st to endNight
27%6%14%22%19%12%
1980
October1st to 10thNight
23%412%25%21%14%
1980
11th to 20thNight
31%48%15%21%20%
2106
21st to endNight
30%36%16%21%23%
2376
November1st to 10thNight
33%5%8%18%23%14%
2220
11th to 20thNight
30%5%8%20%22%15%
2394
21st to endNight
40%46%16%19%15%
2470
December1st to 10thNight
35%48%20%20%11%
2470
11th to 20thNight
41%36%11%22%17%
3037
21st to endNight
35%35%14%29%14%
4532

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
19%15%34%26%41
270
11th to 20thDay
24%14%31%23%7%
270
21st to endDay
21%18%36%20%5%
282
February1st to 10thDay
28%16%31%18%7%
240
11th to 20thDay
25%20%37%16%3
240
21st to endDay
30%20%33%16%1
198
March1st to 10thDay
24%16%39%16%4
240
11th to 20thDay
19%23%34%17%7%
240
21st to endDay
18%19%39%19%5%
264
April1st to 10thDay
22%17%42%16%3
240
11th to 20thDay
18%20%35%19%8%
234
21st to endDay
19%15%38%20%8%
566
May1st to 10thDay
16%12%37%28%7%
603
11th to 20thDay
18%7%29%32%12%2
625
21st to endDay
17%7%26%34%14%2
679
June1st to 10thDay
6%316%42%27%6%
630
11th to 20thDay
9%117%48%20%4
630
21st to endDay
7%313%38%31%9%
630
July1st to 10thDay
7%29%41%31%10%
621
11th to 20thDay
317%38%45%7%
618
21st to endDay
315%35%47%9%
684
August1st to 10thDay
26%35%45%12%
626
11th to 20thDay
6%436%43%11%
489
21st to endDay
5%17%28%38%21%
387
September1st to 10thDay
8%6%20%47%19%
270
11th to 20thDay
8%17%26%44%14%
270
21st to endDay
11%36%30%35%15%
270
October1st to 10thDay
3416%36%33%9%
270
11th to 20thDay
12%6%26%29%23%4
270
21st to endDay
21%12%25%25%14%3
297
November1st to 10thDay
20%7%27%33%9%4
270
11th to 20thDay
18%10%30%28%11%3
270
21st to endDay
22%19%32%18%8%1
270
December1st to 10thDay
15%11%35%25%11%3
270
11th to 20thDay
20%18%33%23%7%
270
21st to endDay
19%13%39%21%7%1
297
January1st to 10thNight
20%11%32%31%7%1
950
11th to 20thNight
20%11%31%31%7%
950
21st to endNight
19%14%32%29%6%
953
February1st to 10thNight
25%11%33%26%5%
720
11th to 20thNight
24%14%35%25%2
704
21st to endNight
26%14%40%18%2
592
March1st to 10thNight
22%14%37%24%4
552
11th to 20thNight
20%12%34%30%4
540
21st to endNight
15%14%43%24%3
594
April1st to 10thNight
15%11%43%28%2
540
11th to 20thNight
20%12%39%25%4
533
21st to endNight
15%11%43%22%9%
540
May1st to 10thNight
14%12%41%28%6%
540
11th to 20thNight
13%7%33%35%12%1
531
21st to endNight
13%7%33%34%13%
584
June1st to 10thNight
4323%45%23%1
540
11th to 20thNight
5%131%48%13%1
540
21st to endNight
7%218%47%23%3
540
July1st to 10thNight
6%116%46%27%4
525
11th to 20thNight
311%56%28%2
522
21st to endNight
3110%53%30%3
591
August1st to 10thNight
19%58%28%4
537
11th to 20thNight
7%18%50%31%3
534
21st to endNight
6%16%47%35%5%
594
September1st to 10thNight
9%110%41%34%5%
540
11th to 20thNight
12%27%40%36%3
540
21st to endNight
11%113%34%37%4
540
October1st to 10thNight
8%114%47%26%4
540
11th to 20thNight
15%424%37%18%2
666
21st to endNight
15%10%25%28%20%1
792
November1st to 10thNight
15%5%24%40%16%1
740
11th to 20thNight
13%9%28%36%14%1
874
21st to endNight
21%10%29%29%11%1
950
December1st to 10thNight
17%9%31%32%10%1
950
11th to 20thNight
23%10%31%30%6%
950
21st to endNight
22%9%30%32%7%
1045
Page generated at 2024-01-24 08:37:32. Version ac07

Copyright 2024 Attilla Danko


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