The Lone Wolf Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Lone Wolf Observatory clear sky chart from 2005-11-05 to 2018-01-20.

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
37%
16507
17%
48461
11%
16465
43%
16465
23%
32572

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 15thNight
20%
975
13%
2716
4%
970
28%
970
17%
1977
January16th to endNight
20%
985
13%
2736
4%
985
28%
985
16%
2070
February1st to 15thNight
22%
776
14%
2187
4%
776
30%
776
18%
1568
February16th to endNight
25%
631
18%
1893
7%
631
35%
631
17%
1339
March1st to 15thNight
25%
720
13%
2160
8%
720
29%
720
17%
1546
March16th to endNight
30%
642
15%
2019
10%
642
37%
642
18%
1423
April1st to 15thNight
30%
539
15%
1797
10%
539
39%
539
20%
1203
April16th to endNight
32%
540
18%
1724
11%
540
42%
540
21%
1165
May1st to 15thNight
37%
540
16%
1620
9%
540
43%
540
22%
1120
May16th to endNight
50%
562
17%
1499
10%
561
55%
561
31%
982
June1st to 15thNight
52%
540
16%
1440
11%
540
56%
540
35%
891
June16th to endNight
50%
540
17%
1440
9%
540
54%
540
32%
948
July1st to 15thNight
62%
510
17%
1360
11%
510
65%
510
39%
823
July16th to endNight
70%
564
22%
1417
17%
531
73%
531
43%
827
August1st to 15thNight
76%
539
22%
1578
22%
536
77%
536
41%
886
August16th to endNight
67%
573
21%
1910
21%
573
71%
573
33%
1085
September1st to 15thNight
62%
555
27%
1815
27%
555
67%
555
35%
1013
September16th to endNight
60%
717
27%
1980
21%
717
63%
717
35%
1196
October1st to 15thNight
47%
720
25%
2052
18%
720
53%
720
31%
1264
October16th to endNight
29%
768
19%
2454
12%
768
38%
768
21%
1603
November1st to 15thNight
29%
760
22%
2471
15%
760
39%
760
23%
1553
November16th to endNight
25%
796
19%
2551
10%
796
35%
796
20%
1690
December1st to 15thNight
19%
975
12%
2730
3%
975
26%
975
16%
2025
December16th to endNight
15%
1040
10%
2912
2%
1040
22%
1040
11%
2375

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%8%36%5%3445%7%36%
49073
Night
14%8%35%424446%39%
48629
Cloud CoverDay
14%8%35%5%3445%7%37%
49082
Night
15%8%35%424446%39%
48634
TransparencyDay
46%6%12%21%12%1
48759
Night
44%5%12%22%13%1
48461
SeeingDay
14%8%29%26%14%5%
6360
Night
18%9%29%28%12%1
16511

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 15thDay
15%15%36%6%35%5%5%5%26%
1552
16th to endDay
12%16%7%9%6%34345%26%
1589
February1st to 15thDay
15%13%7%8%6%35%346%26%
1673
16th to endDay
14%11%5%7%6%25%346%31%
1580
March1st to 15thDay
15%13%47%435%45%6%28%
1790
16th to endDay
18%8%47%5%3445%6%30%
2216
April1st to 15thDay
18%10%46%5%34345%32%
2151
16th to endDay
19%7%25%5%3435%7%35%
2235
May1st to 15thDay
17%9%46%6%3446%7%29%
2331
16th to endDay
12%6%35%5%345%5%8%38%
2615
June1st to 15thDay
10%5%35%5%3445%7%43%
2520
16th to endDay
9%5%25%6%45%7%7%9%36%
2520
July1st to 15thDay
7%425%6%46%46%9%43%
2520
16th to endDay
6%426%5%36%6%7%10%40%
2655
August1st to 15thDay
6%426%6%35%6%6%8%43%
2370
16th to endDay
8%5%245%36%6%6%9%41%
2292
September1st to 15thDay
12%4145%245%47%47%
2132
16th to endDay
8%5%245%345%7%8%43%
1980
October1st to 15thDay
15%7%25%434446%41%
1906
16th to endDay
18%9%35%5%43346%35%
1770
November1st to 15thDay
15%7%25%433447%40%
1717
16th to endDay
17%8%36%424346%38%
1735
December1st to 15thDay
17%11%5%8%6%35%346%28%
1560
16th to endDay
20%15%6%7%6%24435%22%
1664
January1st to 15thNight
17%12%36%5%24335%34%
2716
16th to endNight
13%12%7%7%6%34445%29%
2736
February1st to 15thNight
16%11%5%6%434345%34%
2185
16th to endNight
16%11%47%6%2425%5%33%
1893
March1st to 15thNight
16%11%5%6%5%2443435%
2147
16th to endNight
16%7%37%425%46%7%33%
2019
April1st to 15thNight
16%8%46%42445%6%36%
1797
16th to endNight
19%8%25%433445%38%
1724
May1st to 15thNight
19%6%25%5%246%5%7%34%
1620
16th to endNight
10%435%435%46%8%43%
1497
June1st to 15thNight
9%5%15%5%23447%49%
1440
16th to endNight
9%5%24436%5%6%11%40%
1440
July1st to 15thNight
6%313435%6%5%8%50%
1440
16th to endNight
44244245%7%9%50%
1513
August1st to 15thNight
431343445%10%53%
1587
16th to endNight
8%42342445%9%51%
1910
September1st to 15thNight
10%32442335%6%53%
1815
16th to endNight
7%5%15%42445%7%49%
1980
October1st to 15thNight
13%5%24424247%47%
2052
16th to endNight
19%8%25%323336%40%
2454
November1st to 15thNight
13%8%35%424345%43%
2471
16th to endNight
17%7%46%423347%37%
2551
December1st to 15thNight
19%9%38%5%24445%31%
2730
16th to endNight
22%15%47%5%45%33422%
2912

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 15thDay
15%14%46%5%345%5%6%27%
1552
16th to endDay
13%16%7%8%6%34345%26%
1589
February1st to 15thDay
15%14%6%7%6%35%445%27%
1673
16th to endDay
14%11%48%6%34346%31%
1580
March1st to 15thDay
16%13%37%5%35%45%5%29%
1800
16th to endDay
18%9%46%5%3445%6%31%
2215
April1st to 15thDay
19%9%46%424446%32%
2151
16th to endDay
20%7%2443445%7%36%
2235
May1st to 15thDay
18%9%36%5%345%5%7%30%
2331
16th to endDay
13%5%26%5%345%5%8%39%
2615
June1st to 15thDay
11%5%25%5%2445%7%44%
2520
16th to endDay
10%5%25%6%35%6%7%9%37%
2520
July1st to 15thDay
7%425%5%35%46%9%45%
2520
16th to endDay
7%325%5%36%6%7%10%41%
2655
August1st to 15thDay
7%425%6%346%6%8%44%
2370
16th to endDay
9%424436%5%6%9%42%
2292
September1st to 15thDay
12%5%1443445%6%48%
2132
16th to endDay
8%5%24435%5%7%8%43%
1980
October1st to 15thDay
16%7%235%24436%41%
1906
16th to endDay
19%8%35%5%34346%35%
1770
November1st to 15thDay
15%7%35%423347%40%
1717
16th to endDay
18%8%35%5%24346%38%
1735
December1st to 15thDay
16%13%46%5%35%445%28%
1560
16th to endDay
21%15%6%7%5%24345%23%
1664
January1st to 15thNight
18%11%46%5%23335%34%
2716
16th to endNight
14%12%6%8%5%34445%29%
2736
February1st to 15thNight
16%11%5%6%433345%35%
2178
16th to endNight
16%11%46%6%24345%33%
1893
March1st to 15thNight
17%11%46%5%2443435%
2160
16th to endNight
17%8%35%5%25%36%6%33%
2019
April1st to 15thNight
17%8%46%423447%36%
1797
16th to endNight
19%8%24433445%38%
1724
May1st to 15thNight
20%6%25%5%345%5%7%34%
1619
16th to endNight
11%425%43446%8%43%
1497
June1st to 15thNight
10%425%42345%7%49%
1440
16th to endNight
9%5%24425%5%6%10%40%
1440
July1st to 15thNight
6%223425%5%6%8%50%
1440
16th to endNight
5%3234346%6%9%51%
1513
August1st to 15thNight
4314425%46%8%54%
1587
16th to endNight
9%31342445%8%51%
1910
September1st to 15thNight
10%323432446%53%
1815
16th to endNight
8%42442445%7%50%
1980
October1st to 15thNight
14%424424347%47%
2052
16th to endNight
19%7%25%423345%40%
2454
November1st to 15thNight
14%9%34424345%43%
2471
16th to endNight
17%8%35%424346%38%
2551
December1st to 15thNight
20%9%38%5%23345%32%
2730
16th to endNight
23%14%5%7%5%3433422%
2912

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 15thDay
56%6%12%13%9%
1553
16th to endDay
59%5%12%14%6%
1589
February1st to 15thDay
58%5%10%15%8%1
1675
16th to endDay
54%5%12%20%5%1
1580
March1st to 15thDay
56%6%11%18%7%1
1800
16th to endDay
53%6%13%20%5%
2216
April1st to 15thDay
52%5%8%20%11%
2151
16th to endDay
48%6%13%16%11%3
2235
May1st to 15thDay
52%6%12%21%6%
2331
16th to endDay
42%7%12%20%15%1
2619
June1st to 15thDay
37%6%10%24%18%1
2520
16th to endDay
40%9%13%20%14%2
2520
July1st to 15thDay
36%7%12%25%15%2
2371
16th to endDay
34%9%16%22%14%2
2488
August1st to 15thDay
35%7%14%25%14%1
2355
16th to endDay
35%8%12%24%15%2
2292
September1st to 15thDay
35%5%11%25%19%3
2132
16th to endDay
34%6%11%28%17%1
1980
October1st to 15thDay
42%411%24%13%2
1906
16th to endDay
48%412%22%10%1
1770
November1st to 15thDay
42%5%13%21%14%2
1717
16th to endDay
48%5%12%25%8%
1735
December1st to 15thDay
57%5%11%19%6%
1560
16th to endDay
64%5%10%12%6%
1664
January1st to 15thNight
52%412%17%11%
2716
16th to endNight
55%6%13%16%7%
2736
February1st to 15thNight
52%412%20%9%1
2187
16th to endNight
52%411%21%9%1
1893
March1st to 15thNight
52%5%11%18%9%1
2160
16th to endNight
48%7%12%20%8%1
2019
April1st to 15thNight
47%410%21%14%1
1797
16th to endNight
47%5%9%20%13%3
1724
May1st to 15thNight
46%6%11%23%11%
1620
16th to endNight
36%7%14%20%17%3
1499
June1st to 15thNight
33%5%12%26%19%2
1440
16th to endNight
36%7%13%22%18%1
1440
July1st to 15thNight
29%6%13%26%19%2
1360
16th to endNight
25%7%17%27%18%4
1417
August1st to 15thNight
25%7%17%27%19%2
1578
16th to endNight
29%8%12%26%18%4
1910
September1st to 15thNight
30%410%26%24%3
1815
16th to endNight
32%6%9%29%19%2
1980
October1st to 15thNight
36%49%27%19%2
2052
16th to endNight
45%412%23%13%1
2454
November1st to 15thNight
42%49%23%16%3
2471
16th to endNight
46%413%24%10%
2551
December1st to 15thNight
54%5%10%19%9%
2730
16th to endNight
66%49%14%5%
2912

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 15thDay
24%11%31%25%5%
135
16th to endDay
15%11%41%25%5%
109
February1st to 15thDay
18%18%51%11%
90
16th to endDay
18%14%37%18%7%3
81
March1st to 15thDay
27%20%33%16%2
90
16th to endDay
28%8%31%20%9%1
255
April1st to 15thDay
23%12%28%24%10%
270
16th to endDay
22%11%31%19%12%3
270
May1st to 15thDay
20%12%31%21%9%3
288
16th to endDay
14%9%33%26%11%3
515
June1st to 15thDay
11%6%32%31%13%4
495
16th to endDay
11%7%38%27%10%4
495
July1st to 15thDay
9%429%30%17%8%
475
16th to endDay
7%326%32%20%8%
515
August1st to 15thDay
6%217%35%23%14%
382
16th to endDay
9%316%32%25%12%
332
September1st to 15thDay
12%318%31%26%8%
315
16th to endDay
9%5%18%29%28%8%
314
October1st to 15thDay
22%5%23%28%15%4
241
16th to endDay
22%11%36%26%4
144
November1st to 15thDay
17%8%28%28%12%5%
135
16th to endDay
20%15%42%16%5%
135
December1st to 15thDay
14%21%44%15%3
135
16th to endDay
25%21%45%6%1
144
January1st to 15thNight
22%14%36%20%4
975
16th to endNight
19%14%36%26%3
985
February1st to 15thNight
21%11%39%23%4
779
16th to endNight
22%14%32%25%5%
631
March1st to 15thNight
22%12%35%22%6%
720
16th to endNight
18%11%33%27%8%1
642
April1st to 15thNight
20%13%30%27%7%
539
16th to endNight
22%7%32%25%10%1
540
May1st to 15thNight
22%430%29%12%
540
16th to endNight
13%425%38%18%1
563
June1st to 15thNight
11%324%45%14%
540
16th to endNight
12%128%35%20%1
540
July1st to 15thNight
7%121%40%25%2
510
16th to endNight
6%115%46%26%3
564
August1st to 15thNight
5%10%49%29%5%
539
16th to endNight
10%214%36%31%4
573
September1st to 15thNight
11%415%34%27%5%
555
16th to endNight
9%5%18%34%29%3
717
October1st to 15thNight
16%7%24%32%17%1
720
16th to endNight
24%13%30%23%8%
768
November1st to 15thNight
18%13%35%21%9%1
760
16th to endNight
21%14%34%22%6%
796
December1st to 15thNight
24%14%36%20%4
975
16th to endNight
30%13%34%19%2
1040
Page generated at 2018-01-21 11:19:29. Version ac04

Copyright 2018 A. Danko


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