Klondike
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Klondike clear sky chart from 2005-11-05 to 2017-12-04.

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%
14936
16%
47843
13%
14911
52%
14911
24%
30348

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
28%
716
7%
2506
5%
716
31%
716
8%
2042
January16th to endNight
37%
768
9%
2664
8%
768
40%
768
12%
2030
February1st to 15thNight
44%
697
9%
2288
8%
696
47%
696
15%
1664
February16th to endNight
39%
632
14%
1945
11%
632
45%
632
18%
1346
March1st to 15thNight
40%
720
10%
2118
6%
720
45%
720
18%
1524
March16th to endNight
38%
768
13%
2026
5%
768
42%
768
19%
1445
April1st to 15thNight
37%
719
15%
1799
6%
719
41%
719
24%
1248
April16th to endNight
42%
636
18%
1716
9%
636
47%
636
29%
1086
May1st to 15thNight
49%
359
21%
1439
21%
359
59%
359
29%
728
May16th to endNight
50%
374
13%
1496
15%
374
57%
374
24%
815
June1st to 15thNight
40%
360
13%
1440
11%
360
51%
360
24%
775
June16th to endNight
42%
360
17%
1440
17%
360
56%
360
34%
661
July1st to 15thNight
62%
340
20%
1360
24%
340
74%
340
57%
489
July16th to endNight
63%
376
32%
1416
32%
354
81%
354
60%
487
August1st to 15thNight
68%
429
33%
1501
28%
427
79%
427
58%
588
August16th to endNight
66%
714
37%
1860
21%
714
72%
714
64%
884
September1st to 15thNight
69%
720
34%
1800
18%
720
74%
720
70%
865
September16th to endNight
64%
716
32%
1946
24%
716
67%
716
45%
1052
October1st to 15thNight
54%
720
20%
2160
18%
720
60%
720
32%
1276
October16th to endNight
51%
768
18%
2400
18%
768
55%
768
25%
1548
November1st to 15thNight
41%
760
13%
2529
11%
760
46%
760
16%
1815
November16th to endNight
39%
780
9%
2730
7%
780
43%
780
13%
1991
December1st to 15thNight
34%
736
9%
2576
8%
736
37%
736
11%
1975
December16th to endNight
32%
768
9%
2688
5%
768
36%
768
11%
2014

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
8%6%25%42445%6%48%
48673
Night
9%7%36%5%2445%6%44%
48011
Cloud CoverDay
6%6%25%43445%7%48%
48673
Night
8%7%36%5%3445%6%45%
48015
TransparencyDay
36%6%12%22%15%5%
48344
Night
39%6%14%22%12%4
47844
SeeingDay
12%15%27%25%14%4
5761
Night
12%8%22%33%19%2
14949

By Month

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
15%16%5%11%7%36%6%5%5%16%
1432
16th to endDay
17%13%8%8%5%345%6%6%20%
1558
February1st to 15thDay
15%13%49%6%35%5%5%6%25%
1576
16th to endDay
11%9%36%5%35%7%5%7%32%
1528
March1st to 15thDay
13%8%48%8%46%5%6%6%25%
1839
16th to endDay
10%8%38%7%46%5%5%8%29%
2197
April1st to 15thDay
7%6%36%6%46%6%6%8%37%
2149
16th to endDay
7%5%13435%6%6%8%46%
2243
May1st to 15thDay
5%425%4345%5%8%50%
2511
16th to endDay
9%5%14435%449%46%
2615
June1st to 15thDay
8%31342445%7%53%
2520
16th to endDay
421342345%6%61%
2520
July1st to 15thDay
11112335%77%
2520
16th to endDay
11111122479%
2657
August1st to 15thDay
11112335%76%
2448
16th to endDay
21221232475%
2342
September1st to 15thDay
3111212125%76%
2160
16th to endDay
5%3145%24446%56%
2013
October1st to 15thDay
10%425%6%3445%5%46%
1800
16th to endDay
12%6%26%5%35%46%6%41%
1824
November1st to 15thDay
12%10%47%5%46%5%6%7%28%
1660
16th to endDay
13%11%49%7%36%5%6%6%25%
1560
December1st to 15thDay
15%14%7%7%5%245%45%27%
1465
16th to endDay
16%12%6%9%5%45%35%5%24%
1536
January1st to 15thNight
16%14%6%11%7%34445%20%
2506
16th to endNight
14%11%6%10%6%3445%6%25%
2664
February1st to 15thNight
12%10%47%6%3445%6%32%
2276
16th to endNight
11%7%45%5%35%46%8%36%
1945
March1st to 15thNight
12%7%37%6%46%5%6%8%30%
2118
16th to endNight
8%7%36%6%46%6%7%8%35%
2022
April1st to 15thNight
8%5%35%6%36%6%6%7%39%
1799
16th to endNight
7%5%1442446%8%49%
1716
May1st to 15thNight
5%325%42445%6%56%
1439
16th to endNight
6%425%415%5%6%8%49%
1496
June1st to 15thNight
8%2134245%5%8%52%
1440
16th to endNight
4314323435%64%
1440
July1st to 15thNight
2121223477%
1440
16th to endNight
1111232381%
1512
August1st to 15thNight
111311335%75%
1509
16th to endNight
221211135%77%
1860
September1st to 15thNight
112112225%78%
1800
16th to endNight
431332345%6%61%
1946
October1st to 15thNight
7%5%25%434346%51%
2160
16th to endNight
10%6%25%6%3446%7%42%
2400
November1st to 15thNight
15%8%36%6%35%5%7%7%30%
2529
16th to endNight
13%11%5%6%6%45%447%30%
2730
December1st to 15thNight
15%13%6%8%5%34445%26%
2576
16th to endNight
17%11%5%8%6%2445%7%26%
2688

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
13%17%7%11%6%5%6%5%5%6%15%
1432
16th to endDay
16%15%7%8%7%3445%6%20%
1558
February1st to 15thDay
12%14%5%9%6%35%5%45%25%
1576
16th to endDay
8%8%37%6%46%7%5%8%32%
1528
March1st to 15thDay
9%8%49%7%5%7%6%7%8%24%
1839
16th to endDay
7%9%37%7%46%6%6%9%30%
2197
April1st to 15thDay
5%6%36%6%36%6%7%9%37%
2149
16th to endDay
6%5%24425%5%6%9%48%
2243
May1st to 15thDay
4324435%5%6%8%50%
2511
16th to endDay
7%5%24435%5%5%8%47%
2615
June1st to 15thDay
7%313425%46%7%53%
2520
16th to endDay
3213323447%62%
2520
July1st to 15thDay
11112335%78%
2520
16th to endDay
11111223479%
2657
August1st to 15thDay
111112336%76%
2448
16th to endDay
111222233475%
2342
September1st to 15thDay
212212225%75%
2160
16th to endDay
4324434447%55%
2013
October1st to 15thDay
8%5%25%5%35%36%6%46%
1800
16th to endDay
9%6%26%6%35%5%5%7%40%
1824
November1st to 15thDay
9%11%48%5%36%6%7%9%26%
1660
16th to endDay
11%11%49%9%47%6%6%6%22%
1560
December1st to 15thDay
12%15%7%7%5%2445%6%26%
1465
16th to endDay
14%13%6%8%7%46%45%6%22%
1536
January1st to 15thNight
14%15%7%11%6%345%5%5%20%
2506
16th to endNight
13%11%6%10%7%35%45%6%25%
2664
February1st to 15thNight
10%9%5%8%7%35%46%6%31%
2276
16th to endNight
8%8%37%5%35%5%6%9%36%
1945
March1st to 15thNight
8%7%49%6%35%7%6%9%31%
2118
16th to endNight
6%6%37%7%37%6%6%9%35%
2026
April1st to 15thNight
6%5%36%6%46%5%7%8%40%
1799
16th to endNight
6%4245%2446%8%51%
1716
May1st to 15thNight
5%2135%3445%6%57%
1439
16th to endNight
5%425%4245%7%8%49%
1496
June1st to 15thNight
7%2135%2446%8%53%
1440
16th to endNight
4313323345%64%
1440
July1st to 15thNight
211113235%76%
1440
16th to endNight
11123382%
1512
August1st to 15thNight
112212335%76%
1509
16th to endNight
121212225%77%
1860
September1st to 15thNight
11221223479%
1800
16th to endNight
341232435%6%61%
1946
October1st to 15thNight
6%5%25%5%3345%5%51%
2160
16th to endNight
8%6%25%5%35%45%7%43%
2400
November1st to 15thNight
12%9%37%6%35%5%6%7%31%
2529
16th to endNight
12%11%47%7%35%5%5%7%30%
2730
December1st to 15thNight
13%13%6%9%6%35%45%5%26%
2576
16th to endNight
15%10%5%8%6%34348%26%
2688

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
67%9%11%8%2
1432
16th to endDay
62%6%15%11%3
1558
February1st to 15thDay
58%8%17%14%1
1576
16th to endDay
49%9%17%16%6%
1528
March1st to 15thDay
56%7%13%15%6%
1839
16th to endDay
51%9%15%19%4
2197
April1st to 15thDay
43%8%15%23%8%
2149
16th to endDay
34%8%17%25%12%1
2243
May1st to 15thDay
31%6%11%29%18%2
2511
16th to endDay
36%6%16%26%12%
2619
June1st to 15thDay
32%6%12%29%16%2
2520
16th to endDay
23%411%34%18%6%
2520
July1st to 15thDay
11%38%23%34%18%
2371
16th to endDay
11%36%16%34%28%
2490
August1st to 15thDay
11%37%26%34%16%
2431
16th to endDay
13%37%31%32%11%
2342
September1st to 15thDay
13%27%29%33%13%
2160
16th to endDay
28%5%14%27%18%5%
2013
October1st to 15thDay
38%6%14%24%15%1
1800
16th to endDay
41%8%16%23%9%
1824
November1st to 15thDay
52%9%17%17%3
1660
16th to endDay
57%9%17%12%2
1560
December1st to 15thDay
58%9%12%14%5%
1465
16th to endDay
59%10%14%12%2
1536
January1st to 15thNight
64%8%11%11%3
2506
16th to endNight
59%6%15%14%3
2664
February1st to 15thNight
51%8%19%17%2
2288
16th to endNight
45%9%17%20%6%
1945
March1st to 15thNight
49%7%17%18%5%
2118
16th to endNight
44%10%16%23%4
2026
April1st to 15thNight
41%8%17%24%7%
1799
16th to endNight
32%9%17%27%10%2
1716
May1st to 15thNight
28%5%14%31%17%2
1440
16th to endNight
31%8%23%24%10%1
1496
June1st to 15thNight
30%8%14%30%14%2
1440
16th to endNight
22%411%36%18%5%
1440
July1st to 15thNight
12%212%24%30%18%
1360
16th to endNight
8%35%18%34%28%
1416
August1st to 15thNight
12%36%27%34%15%
1501
16th to endNight
12%28%28%36%12%
1860
September1st to 15thNight
10%29%31%28%18%
1800
16th to endNight
22%413%29%22%7%
1946
October1st to 15thNight
33%5%12%26%19%2
2160
16th to endNight
40%6%14%22%14%1
2400
November1st to 15thNight
51%7%13%21%5%
2529
16th to endNight
53%8%16%17%4
2730
December1st to 15thNight
59%8%13%15%3
2576
16th to endNight
57%7%17%13%3
2688

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
25%316%23%25%6%
60
16th to endDay
34%419%19%19%1
86
February1st to 15thDay
22%9%22%33%11%
236
16th to endDay
17%17%27%27%8%1
229
March1st to 15thDay
23%16%27%24%7%
270
16th to endDay
20%23%31%17%6%
288
April1st to 15thDay
13%23%28%20%8%4
269
16th to endDay
15%27%28%15%10%2
270
May1st to 15thDay
13%18%30%24%8%3
288
16th to endDay
13%16%24%26%14%5%
330
June1st to 15thDay
11%21%23%24%12%5%
315
16th to endDay
10%16%30%26%12%3
315
July1st to 15thDay
39%34%31%19%2
305
16th to endDay
29%37%28%15%6%
327
August1st to 15thDay
410%26%24%22%12%
315
16th to endDay
39%24%25%29%7%
332
September1st to 15thDay
5%11%26%29%18%8%
315
16th to endDay
8%13%27%28%20%2
315
October1st to 15thDay
14%18%23%26%14%2
315
16th to endDay
15%13%23%29%14%4
240
November1st to 15thDay
18%16%29%29%5%
121
16th to endDay
22%14%23%28%8%2
90
December1st to 15thDay
33%18%24%21%3
66
16th to endDay
49%29%35%18%1
64
January1st to 15thNight
22%9%20%29%16%1
720
16th to endNight
20%6%16%32%20%4
768
February1st to 15thNight
17%7%18%35%19%1
704
16th to endNight
15%12%22%32%15%1
632
March1st to 15thNight
13%11%22%37%14%
720
16th to endNight
13%14%25%30%14%1
768
April1st to 15thNight
10%14%29%27%15%1
719
16th to endNight
11%13%28%27%16%2
636
May1st to 15thNight
8%9%25%33%20%2
360
16th to endNight
9%8%25%35%17%3
375
June1st to 15thNight
9%11%33%31%12%1
360
16th to endNight
6%13%31%29%18%
360
July1st to 15thNight
2429%40%21%2
340
16th to endNight
15%28%41%21%1
376
August1st to 15thNight
2421%38%26%6%
429
16th to endNight
45%21%30%31%7%
714
September1st to 15thNight
25%20%29%34%7%
720
16th to endNight
7%7%15%34%29%5%
716
October1st to 15thNight
9%6%22%36%22%3
720
16th to endNight
12%6%20%34%22%3
768
November1st to 15thNight
20%9%18%38%11%1
760
16th to endNight
20%8%19%30%17%3
780
December1st to 15thNight
21%8%19%33%15%1
736
16th to endNight
22%9%21%33%12%
768
Page generated at 2017-12-05 07:19:04. Version ac04

Copyright 2017 A. Danko


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