Kevin's Cabin
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kevin's Cabin clear sky chart from 2005-11-05 to 2018-11-30.

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
31%
17945
12%
51606
7%
17898
36%
17898
19%
37550

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
25%
975
8%
2910
5%
970
29%
970
13%
2268
January16th to endNight
20%
1040
9%
2953
3%
1040
25%
1040
12%
2392
February1st to 15thNight
30%
954
13%
2483
5%
950
36%
950
20%
1819
February16th to endNight
30%
854
13%
2220
4%
854
36%
854
18%
1673
March1st to 15thNight
29%
653
16%
2213
9%
653
37%
653
17%
1532
March16th to endNight
32%
624
15%
2271
12%
624
39%
624
16%
1538
April1st to 15thNight
33%
584
17%
1921
12%
584
43%
584
22%
1250
April16th to endNight
31%
579
16%
1730
10%
579
38%
579
21%
1188
May1st to 15thNight
32%
585
15%
1560
5%
585
36%
585
23%
1097
May16th to endNight
40%
611
10%
1564
4%
609
43%
609
28%
1073
June1st to 15thNight
41%
585
6%
1365
3%
585
44%
585
32%
943
June16th to endNight
45%
585
5%
1365
3%
585
47%
585
30%
969
July1st to 15thNight
53%
555
10%
1295
6%
555
55%
555
42%
827
July16th to endNight
55%
612
16%
1426
7%
579
56%
579
42%
869
August1st to 15thNight
58%
575
20%
1640
11%
572
62%
572
38%
952
August16th to endNight
52%
621
20%
1885
17%
621
58%
621
36%
1074
September1st to 15thNight
49%
585
16%
1950
16%
585
55%
585
30%
1165
September16th to endNight
34%
622
15%
2149
12%
622
40%
622
19%
1429
October1st to 15thNight
30%
780
13%
2340
9%
780
33%
780
17%
1686
October16th to endNight
22%
876
11%
2605
4%
876
29%
876
14%
2000
November1st to 15thNight
20%
1025
9%
2871
4%
1025
24%
1025
12%
2311
November16th to endNight
19%
1050
8%
2939
5%
1050
23%
1050
10%
2448
December1st to 15thNight
18%
975
6%
2831
2%
975
22%
975
9%
2385
December16th to endNight
15%
1040
8%
3120
3%
1040
20%
1040
8%
2662

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
14%10%47%6%35%45%6%31%
52725
Night
13%10%47%6%35%5%5%6%31%
51758
Cloud CoverDay
13%9%36%5%344418%27%
52735
Night
11%8%37%6%344418%27%
51761
Cloud CoverDay
14%10%47%6%35%45%6%31%
52736
Night
13%10%47%6%345%5%6%31%
51762
Cloud CoverDay
15%10%47%6%3445%6%31%
52734
Night
13%10%48%6%35%45%6%31%
51762
TransparencyDay
52%5%12%20%7%
52395
Night
52%5%12%20%7%
51606
SeeingDay
19%11%32%23%10%2
7846
Night
17%8%32%28%11%1
17946

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
12%12%7%10%5%45%7%7%7%20%
1358
16th to endDay
11%13%8%12%8%5%6%7%6%5%12%
1620
February1st to 15thDay
7%9%5%10%8%5%7%6%6%8%24%
1710
16th to endDay
9%13%5%9%6%5%5%6%6%5%25%
1539
March1st to 15thDay
11%11%6%8%6%1445%6%32%
2078
16th to endDay
14%13%47%6%3335%6%30%
2304
April1st to 15thDay
11%10%35%435%5%5%6%36%
2356
16th to endDay
17%10%35%5%33335%36%
2505
May1st to 15thDay
19%11%46%434347%31%
2721
16th to endDay
19%6%25%5%3445%7%35%
2901
June1st to 15thDay
18%6%36%5%35%45%7%33%
2925
16th to endDay
16%6%36%7%35%5%6%7%29%
2925
July1st to 15thDay
12%4245%35%5%6%8%41%
2925
16th to endDay
10%6%25%5%35%5%6%8%40%
3004
August1st to 15thDay
10%6%35%5%35%5%6%9%38%
2564
16th to endDay
13%5%25%423448%42%
2668
September1st to 15thDay
12%6%25%6%34447%41%
2340
16th to endDay
21%7%25%423346%36%
2124
October1st to 15thDay
20%15%47%5%24345%26%
1950
16th to endDay
22%17%47%433245%25%
1970
November1st to 15thDay
16%17%7%9%5%2443422%
1647
16th to endDay
14%16%7%16%10%5%5%33314%
1676
December1st to 15thDay
12%15%7%13%11%6%6%6%3412%
1459
16th to endDay
11%17%7%15%10%5%5%45%411%
1456
January1st to 15thNight
10%11%6%9%8%46%7%6%6%20%
2910
16th to endNight
10%13%6%11%8%47%7%8%7%15%
2953
February1st to 15thNight
7%8%49%7%37%7%7%7%28%
2480
16th to endNight
8%10%5%9%7%45%6%6%6%27%
2220
March1st to 15thNight
10%12%47%5%35%447%32%
2201
16th to endNight
15%9%47%5%34445%35%
2271
April1st to 15thNight
13%9%35%5%25%45%7%37%
1921
16th to endNight
17%9%37%5%24435%37%
1730
May1st to 15thNight
19%7%35%5%2445%6%35%
1560
16th to endNight
17%4245%24447%40%
1562
June1st to 15thNight
17%41442445%6%43%
1365
16th to endNight
14%426%6%35%45%8%39%
1365
July1st to 15thNight
7%212425%5%410%51%
1365
16th to endNight
6%31442345%9%53%
1516
August1st to 15thNight
9%32342346%7%53%
1649
16th to endNight
10%41332246%7%52%
1885
September1st to 15thNight
10%425%5%23347%48%
1950
16th to endNight
18%8%36%323346%38%
2149
October1st to 15thNight
16%12%45%5%34447%32%
2340
16th to endNight
18%14%37%6%34445%26%
2605
November1st to 15thNight
15%16%7%9%7%33445%22%
2871
16th to endNight
15%13%7%10%10%45%44419%
2939
December1st to 15thNight
10%12%7%12%11%5%7%5%6%5%14%
2831
16th to endNight
13%15%8%14%10%45%5%5%411%
3120

Percentage Cloud Cover NW (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
7%10%410%4347%6%21%18%
1359
16th to endDay
8%12%5%11%7%36%6%6%20%10%
1620
February1st to 15thDay
7%8%49%7%46%5%5%20%20%
1710
16th to endDay
7%11%47%5%445%419%24%
1539
March1st to 15thDay
9%9%38%4234420%28%
2089
16th to endDay
9%12%37%6%243320%27%
2302
April1st to 15thDay
9%9%3442445%21%31%
2356
16th to endDay
15%10%25%4233319%29%
2505
May1st to 15thDay
16%9%25%4232321%27%
2721
16th to endDay
16%6%244233321%31%
2901
June1st to 15thDay
16%5%25%4234421%27%
2925
16th to endDay
14%5%35%5%344421%26%
2925
July1st to 15thDay
17%41442345%16%36%
2925
16th to endDay
9%5%2443445%21%33%
3004
August1st to 15thDay
9%5%246%345%6%16%36%
2564
16th to endDay
13%5%15%42345%14%39%
2668
September1st to 15thDay
12%5%25%6%243414%37%
2340
16th to endDay
18%7%25%4232413%35%
2124
October1st to 15thDay
19%14%36%5%232412%24%
1950
16th to endDay
19%15%36%4232412%25%
1970
November1st to 15thDay
13%15%38%5%234316%22%
1647
16th to endDay
12%14%5%14%9%343317%10%
1676
December1st to 15thDay
9%13%5%10%8%5%7%5%319%11%
1459
16th to endDay
8%14%5%13%8%45%35%19%9%
1456
January1st to 15thNight
7%10%38%7%35%7%6%20%19%
2910
16th to endNight
8%12%49%7%35%6%7%21%13%
2953
February1st to 15thNight
6%8%29%6%35%5%5%21%24%
2473
16th to endNight
5%9%38%6%345%5%20%26%
2220
March1st to 15thNight
8%9%36%5%344320%30%
2213
16th to endNight
12%8%36%4233320%30%
2269
April1st to 15thNight
11%7%2442445%21%31%
1921
16th to endNight
15%8%26%4334219%29%
1730
May1st to 15thNight
14%6%233334421%31%
1559
16th to endNight
14%4144233422%35%
1563
June1st to 15thNight
15%4133223421%36%
1365
16th to endNight
12%4144333422%34%
1365
July1st to 15thNight
12%1123243418%45%
1365
16th to endNight
7%2133234422%43%
1516
August1st to 15thNight
8%31332345%15%49%
1649
16th to endNight
9%31332245%14%48%
1885
September1st to 15thNight
10%4145%233414%44%
1950
16th to endNight
16%6%25%4233313%38%
2149
October1st to 15thNight
16%11%25%5%234414%29%
2340
16th to endNight
16%13%36%5%334413%25%
2605
November1st to 15thNight
12%14%5%9%5%234318%21%
2871
16th to endNight
12%12%5%9%9%243417%16%
2939
December1st to 15thNight
7%11%411%9%5%5%45%19%13%
2831
16th to endNight
10%13%5%12%9%3445%20%9%
3120

Percentage Cloud Cover SW (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
12%12%8%9%6%45%7%6%7%20%
1358
16th to endDay
11%13%8%12%8%47%7%7%5%13%
1620
February1st to 15thDay
7%9%411%8%5%8%5%5%8%24%
1710
16th to endDay
9%13%6%8%6%45%6%5%5%26%
1539
March1st to 15thDay
12%11%6%8%5%2445%6%31%
2089
16th to endDay
14%13%47%7%34346%30%
2304
April1st to 15thDay
11%10%35%5%25%5%5%7%36%
2356
16th to endDay
17%11%36%5%24335%35%
2505
May1st to 15thDay
20%11%36%5%24347%30%
2721
16th to endDay
19%6%25%5%24447%35%
2901
June1st to 15thDay
18%6%36%5%35%5%5%7%33%
2925
16th to endDay
16%7%36%6%45%5%6%7%30%
2925
July1st to 15thDay
12%5%24435%5%6%8%41%
2925
16th to endDay
10%5%25%5%35%5%6%7%40%
3004
August1st to 15thDay
10%6%35%6%35%5%6%9%37%
2564
16th to endDay
13%6%244335%5%7%42%
2668
September1st to 15thDay
12%6%35%6%34446%41%
2340
16th to endDay
21%8%26%42335%6%35%
2124
October1st to 15thDay
20%15%37%5%2334427%
1950
16th to endDay
22%17%46%5%23235%26%
1970
November1st to 15thDay
16%17%8%8%6%1443423%
1647
16th to endDay
14%16%6%16%10%4444314%
1676
December1st to 15thDay
12%16%6%13%10%6%7%5%3412%
1459
16th to endDay
12%17%7%14%10%5%5%46%412%
1456
January1st to 15thNight
10%11%6%9%8%46%7%6%6%21%
2910
16th to endNight
10%12%6%10%9%46%7%8%6%16%
2953
February1st to 15thNight
7%9%310%7%37%6%7%7%28%
2473
16th to endNight
8%11%5%9%7%45%6%6%6%28%
2220
March1st to 15thNight
11%12%47%5%345%47%33%
2213
16th to endNight
15%9%47%5%34446%35%
2271
April1st to 15thNight
13%9%35%5%25%45%7%37%
1921
16th to endNight
17%9%37%5%24435%37%
1730
May1st to 15thNight
18%8%3443445%6%35%
1559
16th to endNight
18%4345%2345%7%41%
1562
June1st to 15thNight
18%41442345%6%43%
1365
16th to endNight
13%425%5%35%448%40%
1365
July1st to 15thNight
7%21342445%10%51%
1365
16th to endNight
6%31342445%9%53%
1516
August1st to 15thNight
8%3133245%5%7%53%
1649
16th to endNight
11%41332345%8%52%
1885
September1st to 15thNight
10%425%5%33346%49%
1950
16th to endNight
18%8%26%5%23346%38%
2149
October1st to 15thNight
16%12%36%5%24447%32%
2340
16th to endNight
18%14%47%5%35%35%6%26%
2605
November1st to 15thNight
15%16%6%9%6%33445%23%
2871
16th to endNight
15%13%7%10%10%45%44419%
2939
December1st to 15thNight
10%12%7%12%12%5%7%5%6%5%14%
2831
16th to endNight
14%14%8%14%10%45%5%5%411%
3120

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
12%12%6%11%5%45%7%6%7%20%
1358
16th to endDay
11%13%8%12%9%47%7%7%5%12%
1620
February1st to 15thDay
8%9%5%10%8%5%7%6%6%7%25%
1710
16th to endDay
10%12%7%8%6%45%6%6%5%26%
1539
March1st to 15thDay
11%13%6%8%5%24446%31%
2089
16th to endDay
14%13%46%5%34346%30%
2302
April1st to 15thDay
11%10%35%5%25%45%7%37%
2356
16th to endDay
18%11%35%5%23335%36%
2505
May1st to 15thDay
20%10%35%5%34346%31%
2721
16th to endDay
19%7%25%5%2445%7%35%
2901
June1st to 15thDay
18%6%26%6%3445%6%33%
2925
16th to endDay
17%6%37%6%35%45%7%30%
2925
July1st to 15thDay
12%5%245%35%5%6%8%41%
2925
16th to endDay
11%6%25%5%35%5%6%7%40%
3004
August1st to 15thDay
11%6%35%435%5%6%9%38%
2564
16th to endDay
14%5%245%33447%43%
2668
September1st to 15thDay
13%6%25%5%33446%42%
2340
16th to endDay
21%8%25%433445%36%
2124
October1st to 15thDay
21%14%46%5%34335%27%
1950
16th to endDay
23%16%46%423235%25%
1970
November1st to 15thDay
16%17%8%9%5%2444422%
1647
16th to endDay
14%16%7%15%10%5%5%33314%
1676
December1st to 15thDay
12%16%6%13%11%5%6%5%35%12%
1459
16th to endDay
11%17%8%14%10%45%45%5%11%
1456
January1st to 15thNight
10%11%6%10%8%47%7%6%5%21%
2910
16th to endNight
10%13%6%10%9%46%6%8%6%16%
2953
February1st to 15thNight
7%9%410%7%37%6%6%7%29%
2473
16th to endNight
8%11%5%9%7%36%6%6%6%27%
2220
March1st to 15thNight
11%12%47%5%25%446%33%
2213
16th to endNight
16%9%46%5%33446%35%
2271
April1st to 15thNight
13%9%35%6%24447%38%
1921
16th to endNight
16%9%46%5%24345%37%
1730
May1st to 15thNight
19%7%36%32445%7%35%
1559
16th to endNight
19%42442345%7%41%
1562
June1st to 15thNight
18%41342445%6%43%
1365
16th to endNight
14%425%6%3445%9%39%
1365
July1st to 15thNight
8%2134246%5%8%51%
1365
16th to endNight
8%21442346%8%53%
1516
August1st to 15thNight
8%32342345%7%53%
1649
16th to endNight
11%31332345%7%53%
1885
September1st to 15thNight
11%426%5%24247%49%
1950
16th to endNight
19%8%36%423246%38%
2149
October1st to 15thNight
16%12%36%5%24447%32%
2340
16th to endNight
19%13%36%5%2445%6%26%
2605
November1st to 15thNight
16%16%6%9%7%34445%23%
2871
16th to endNight
15%13%7%10%9%35%44419%
2939
December1st to 15thNight
10%13%6%12%12%5%6%5%6%5%14%
2831
16th to endNight
14%15%8%14%10%35%5%5%5%11%
3120

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
60%6%10%17%5%
1359
16th to endDay
68%6%8%12%3
1620
February1st to 15thDay
55%6%12%16%8%
1711
16th to endDay
57%5%10%19%6%
1539
March1st to 15thDay
52%5%13%18%8%
2089
16th to endDay
54%413%18%6%1
2304
April1st to 15thDay
45%5%9%22%16%
2356
16th to endDay
51%39%21%13%
2505
May1st to 15thDay
53%410%21%9%
2721
16th to endDay
48%5%11%20%12%
2905
June1st to 15thDay
49%6%13%21%8%
2925
16th to endDay
50%7%14%19%6%
2925
July1st to 15thDay
36%7%14%28%11%
2766
16th to endDay
41%7%15%25%9%
2831
August1st to 15thDay
40%7%19%25%7%
2549
16th to endDay
39%5%17%28%8%
2668
September1st to 15thDay
41%5%16%28%7%
2340
16th to endDay
49%5%17%23%3
2124
October1st to 15thDay
60%412%17%4
1950
16th to endDay
62%411%17%3
1970
November1st to 15thDay
64%5%11%12%4
1647
16th to endDay
75%5%7%9%2
1676
December1st to 15thDay
74%5%8%9%1
1459
16th to endDay
73%48%8%4
1456
January1st to 15thNight
60%6%10%17%5%
2910
16th to endNight
63%7%9%17%2
2953
February1st to 15thNight
50%6%15%19%8%
2483
16th to endNight
54%5%12%20%6%
2220
March1st to 15thNight
49%5%12%19%11%
2213
16th to endNight
51%412%20%9%2
2271
April1st to 15thNight
45%310%23%15%1
1921
16th to endNight
49%38%21%15%1
1730
May1st to 15thNight
48%5%10%24%11%
1560
16th to endNight
42%5%13%21%14%2
1564
June1st to 15thNight
40%5%14%24%13%
1365
16th to endNight
41%7%17%24%7%
1365
July1st to 15thNight
27%8%17%32%13%1
1295
16th to endNight
27%6%16%33%14%1
1426
August1st to 15thNight
28%7%16%33%13%1
1640
16th to endNight
30%5%18%33%11%
1885
September1st to 15thNight
35%5%17%31%9%
1950
16th to endNight
47%5%16%25%5%
2149
October1st to 15thNight
51%6%13%21%6%
2340
16th to endNight
58%6%12%19%3
2605
November1st to 15thNight
63%6%11%13%3
2871
16th to endNight
68%6%10%11%3
2939
December1st to 15thNight
69%6%11%10%2
2831
16th to endNight
73%47%11%2
3120

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
16%17%32%21%11%
135
16th to endDay
22%9%38%20%7%1
144
February1st to 15thDay
11%20%40%23%3
135
16th to endDay
23%16%43%13%11
120
March1st to 15thDay
12%12%34%22%16%1
135
16th to endDay
20%15%33%21%6%3
160
April1st to 15thDay
13%11%36%26%9%1
355
16th to endDay
25%12%29%24%7%
511
May1st to 15thDay
24%14%35%16%6%2
543
16th to endDay
22%11%31%22%9%2
597
June1st to 15thDay
20%14%36%18%7%3
570
16th to endDay
18%10%32%21%11%4
570
July1st to 15thDay
14%12%27%30%11%3
550
16th to endDay
11%10%28%27%15%6%
595
August1st to 15thDay
12%7%30%26%17%6%
549
16th to endDay
16%7%27%29%16%2
580
September1st to 15thDay
15%8%31%28%13%1
375
16th to endDay
31%15%30%14%6%
213
October1st to 15thDay
32%15%31%13%6%
180
16th to endDay
30%16%33%14%31
192
November1st to 15thDay
23%13%32%21%8%
180
16th to endDay
34%15%36%9%2
178
December1st to 15thDay
21%8%33%28%6%
135
16th to endDay
11%11%42%24%6%2
144
January1st to 15thNight
16%10%37%23%10%1
975
16th to endNight
16%11%39%26%5%
1040
February1st to 15thNight
12%8%35%31%10%1
955
16th to endNight
14%9%36%26%9%3
854
March1st to 15thNight
13%12%35%27%9%1
653
16th to endNight
21%8%29%24%12%3
624
April1st to 15thNight
17%9%33%28%10%
584
16th to endNight
21%7%31%29%9%
579
May1st to 15thNight
22%7%33%29%6%1
585
16th to endNight
20%6%28%29%13%1
611
June1st to 15thNight
19%5%29%32%12%
585
16th to endNight
14%6%26%32%18%1
585
July1st to 15thNight
9%5%27%37%19%
555
16th to endNight
9%326%34%22%2
612
August1st to 15thNight
9%224%37%21%3
575
16th to endNight
12%427%32%21%1
621
September1st to 15thNight
13%5%27%33%18%1
585
16th to endNight
23%8%29%25%13%
622
October1st to 15thNight
24%11%27%30%5%
780
16th to endNight
27%10%32%21%6%1
876
November1st to 15thNight
23%11%33%23%6%1
1025
16th to endNight
22%12%37%21%6%
1050
December1st to 15thNight
16%9%37%27%8%1
975
16th to endNight
20%10%35%23%8%1
1040
Page generated at 2018-12-01 11:35:37. Version ac04

Copyright 2018 A. Danko


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