Snow Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Snow Lake clear sky chart from 2005-11-06 to 2024-02-05.

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%
24563
9%
80988
5%
24470
35%
24470
15%
59964

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
25%
940
7%
5023
6%
926
31%
926
6%
3950
January11th to 20thNight
21%
945
6%
4887
6%
930
26%
930
7%
4077
January21st to endNight
21%
1038
5%
5039
3%
1023
26%
1023
5%
4105
February1st to 10thNight
30%
923
12%
2583
5%
923
36%
923
18%
1884
February11th to 20thNight
31%
874
13%
2401
6%
874
36%
874
19%
1755
February21st to endNight
31%
660
16%
1844
6%
660
38%
660
19%
1342
March1st to 10thNight
38%
720
15%
2160
11%
720
42%
720
18%
1561
March11th to 20thNight
30%
612
15%
2052
9%
612
40%
612
18%
1397
March21st to endNight
39%
594
19%
2081
16%
594
49%
594
21%
1336
April1st to 10thNight
41%
540
16%
1742
13%
540
49%
540
23%
1130
April11th to 20thNight
36%
533
15%
1599
9%
533
42%
533
23%
1094
April21st to endNight
36%
540
17%
1544
7%
540
41%
540
28%
982
May1st to 10thNight
31%
540
7%
1310
4%
540
33%
540
24%
953
May11th to 20thNight
34%
531
3%
1241
2%
531
36%
531
31%
856
May21st to endNight
36%
583
0%
1357
0%
581
36%
581
28%
970
June1st to 10thNight
38%
360
0%
1080
0%
360
38%
360
22%
725
June11th to 20thNight
38%
360
0%
1080
0%
360
38%
360
19%
777
June21st to endNight
48%
360
0%
1080
0%
360
48%
360
24%
722
July1st to 10thNight
48%
350
0%
1050
0%
350
48%
350
28%
670
July11th to 20thNight
49%
377
0%
1073
0%
377
49%
377
26%
726
July21st to endNight
52%
591
1%
1302
1%
558
53%
558
28%
937
August1st to 10thNight
51%
537
8%
1358
4%
534
54%
534
34%
872
August11th to 20thNight
45%
534
11%
1442
5%
534
48%
534
29%
952
August21st to endNight
38%
594
11%
1782
4%
594
43%
594
21%
1235
September1st to 10thNight
38%
540
12%
1701
9%
540
45%
540
24%
1104
September11th to 20thNight
38%
540
11%
1934
10%
540
43%
540
18%
1296
September21st to endNight
34%
540
18%
1980
13%
540
44%
540
19%
1293
October1st to 10thNight
28%
656
14%
2096
9%
656
34%
656
16%
1529
October11th to 20thNight
28%
900
9%
2340
5%
900
31%
900
16%
1816
October21st to endNight
19%
990
8%
2579
2%
990
23%
990
9%
2199
November1st to 10thNight
19%
925
7%
2662
3%
925
22%
925
8%
2263
November11th to 20thNight
19%
950
6%
2850
2%
950
22%
950
9%
2368
November21st to endNight
18%
950
4%
2850
2%
950
21%
950
7%
2422
December1st to 10thNight
24%
950
5%
2850
2%
950
28%
950
8%
2381
December11th to 20thNight
24%
950
9%
3670
5%
949
30%
949
8%
2795
December21st to endNight
30%
1036
5%
5366
5%
1026
35%
1026
8%
3490

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%10%49%7%45%5%6%7%30%
77412
Night
11%11%5%10%8%46%5%6%7%28%
81408
TransparencyDay
52%7%14%19%7%
77101
Night
55%7%13%18%7%
81300
SeeingDay
17%12%32%26%11%3
14989
Night
17%9%32%29%12%2
24599

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 10thDay
6%12%6%18%14%5%7%7%6%5%14%
1899
11th to 20thDay
5%10%7%19%15%6%7%6%6%8%12%
2045
21st to endDay
8%17%10%15%9%46%5%6%5%15%
2616
February1st to 10thDay
5%12%47%8%6%9%8%8%8%24%
1472
11th to 20thDay
8%10%5%8%7%47%9%8%7%26%
1446
21st to endDay
49%5%11%12%6%7%48%9%25%
1428
March1st to 10thDay
8%13%5%9%9%6%5%45%6%30%
1800
11th to 20thDay
11%9%6%9%8%35%45%6%34%
1906
21st to endDay
10%9%49%6%46%5%5%7%36%
2272
April1st to 10thDay
8%9%49%7%45%6%5%6%37%
2218
11th to 20thDay
10%9%410%8%46%446%35%
2312
21st to endDay
9%8%38%7%45%5%6%7%37%
2414
May1st to 10thDay
18%9%37%6%46%5%5%6%30%
2650
11th to 20thDay
11%6%25%5%35%5%6%8%43%
2655
21st to endDay
18%8%36%42345%8%39%
2918
June1st to 10thDay
18%8%48%7%35%45%6%33%
2879
11th to 20thDay
21%7%36%5%445%5%8%31%
2880
21st to endDay
17%7%37%6%46%5%6%8%31%
2880
July1st to 10thDay
15%435%6%46%5%7%8%38%
2880
11th to 20thDay
15%5%25%6%45%5%6%8%38%
2849
21st to endDay
14%6%36%5%46%6%7%8%36%
2939
August1st to 10thDay
11%6%26%6%45%5%6%8%40%
2571
11th to 20thDay
13%436%7%46%6%7%9%36%
2459
21st to endDay
21%7%36%5%35%5%5%7%32%
2574
September1st to 10thDay
15%7%26%6%45%5%6%7%36%
2256
11th to 20thDay
19%10%36%7%3446%7%31%
2026
21st to endDay
15%10%37%6%3346%7%35%
1980
October1st to 10thDay
18%16%47%5%45%35%7%27%
1843
11th to 20thDay
17%19%6%9%7%4445%6%20%
1620
21st to endDay
18%20%8%11%8%3444415%
1776
November1st to 10thDay
17%16%7%12%11%5%5%445%14%
1415
11th to 20thDay
12%14%6%13%13%7%5%33421%
1330
21st to endDay
9%19%8%14%10%6%6%6%45%13%
1330
December1st to 10thDay
6%12%6%15%14%6%7%6%7%6%16%
1330
11th to 20thDay
12%15%6%11%12%5%5%5%6%7%17%
1454
21st to endDay
7%8%411%10%6%7%6%6%6%29%
2090
January1st to 10thNight
6%11%7%13%13%6%9%7%7%7%16%
5046
11th to 20thNight
5%9%6%20%17%6%8%6%7%6%12%
4856
21st to endNight
10%18%7%14%8%46%7%5%5%15%
5051
February1st to 10thNight
6%10%5%8%8%5%8%9%8%9%24%
2583
11th to 20thNight
8%9%5%9%7%46%9%7%8%27%
2400
21st to endNight
5%10%6%10%10%5%7%5%6%7%30%
1844
March1st to 10thNight
8%12%5%10%8%46%5%5%433%
2160
11th to 20thNight
11%10%5%7%7%446%5%6%35%
2052
21st to endNight
8%10%46%5%46%5%6%6%40%
2081
April1st to 10thNight
11%9%37%6%345%5%8%38%
1742
11th to 20thNight
10%10%5%8%7%345%5%6%37%
1599
21st to endNight
7%8%47%6%35%45%7%43%
1544
May1st to 10thNight
17%8%35%6%36%5%45%36%
1310
11th to 20thNight
15%6%36%5%2345%7%44%
1241
21st to endNight
17%7%46%6%34346%42%
1357
June1st to 10thNight
16%7%35%6%4445%8%38%
1080
11th to 20thNight
20%6%26%6%445%5%8%33%
1080
21st to endNight
16%5%25%6%35%7%6%7%38%
1080
July1st to 10thNight
11%5%26%4345%6%8%45%
1080
11th to 20thNight
11%6%25%5%35%7%8%8%40%
1109
21st to endNight
14%5%25%7%35%47%9%39%
1379
August1st to 10thNight
10%425%445%46%8%49%
1365
11th to 20thNight
13%5%25%5%35%46%8%44%
1442
21st to endNight
17%7%36%4445%6%8%35%
1782
September1st to 10thNight
16%6%245%3445%8%42%
1701
11th to 20thNight
17%9%36%5%345%5%7%37%
1934
21st to endNight
16%9%345%3445%7%39%
1980
October1st to 10thNight
17%12%36%7%345%47%31%
2096
11th to 20thNight
18%13%5%7%6%44447%28%
2340
21st to endNight
20%19%6%9%7%45%44418%
2579
November1st to 10thNight
17%16%7%12%10%35%446%16%
2662
11th to 20thNight
13%15%6%14%10%5%5%446%18%
2850
21st to endNight
10%15%7%15%12%6%6%45%5%15%
2850
December1st to 10thNight
7%12%8%13%11%6%9%7%6%6%14%
2850
11th to 20thNight
9%12%5%11%10%5%7%6%6%7%22%
3737
21st to endNight
6%11%5%8%10%6%5%6%6%7%30%
5566

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
69%6%10%13%2
1899
11th to 20thDay
71%48%13%4
2065
21st to endDay
69%6%12%9%4
2616
February1st to 10thDay
52%7%15%18%7%1
1472
11th to 20thDay
51%6%15%18%10%
1454
21st to endDay
54%5%12%22%7%
1428
March1st to 10thDay
56%413%17%9%1
1800
11th to 20thDay
51%6%13%20%9%1
1908
21st to endDay
46%7%14%24%7%2
2272
April1st to 10thDay
46%6%12%22%13%1
2218
11th to 20thDay
51%5%10%21%14%1
2312
21st to endDay
44%6%11%24%14%1
2414
May1st to 10thDay
52%6%11%20%10%
2650
11th to 20thDay
38%7%12%25%16%3
2659
21st to endDay
44%6%10%26%13%1
2918
June1st to 10thDay
51%6%10%22%11%
2879
11th to 20thDay
50%8%13%20%8%
2880
21st to endDay
49%9%14%21%6%
2880
July1st to 10thDay
42%9%15%26%8%
2801
11th to 20thDay
42%9%17%26%6%
2762
21st to endDay
43%11%19%24%4
2776
August1st to 10thDay
39%11%19%25%5%
2554
11th to 20thDay
42%11%23%21%3
2459
21st to endDay
51%9%22%15%4
2574
September1st to 10thDay
45%10%18%22%6%
2256
11th to 20thDay
51%8%18%20%2
2026
21st to endDay
48%7%19%22%4
1980
October1st to 10thDay
57%5%14%20%4
1843
11th to 20thDay
65%7%14%12%2
1620
21st to endDay
72%6%9%10%2
1776
November1st to 10thDay
75%410%7%3
1415
11th to 20thDay
68%5%11%13%2
1330
21st to endDay
72%6%13%7%1
1330
December1st to 10thDay
66%6%12%11%5%
1330
11th to 20thDay
66%8%11%11%4
1455
21st to endDay
51%7%9%21%9%2
2090
January1st to 10thNight
65%7%12%13%3
5046
11th to 20thNight
71%6%8%12%3
4898
21st to endNight
68%8%10%10%4
5051
February1st to 10thNight
51%7%14%19%8%
2583
11th to 20thNight
51%6%13%20%10%
2402
21st to endNight
52%5%13%21%9%
1844
March1st to 10thNight
54%5%11%20%9%1
2160
11th to 20thNight
49%6%12%22%11%1
2052
21st to endNight
42%7%12%27%9%2
2081
April1st to 10thNight
43%6%11%22%15%2
1742
11th to 20thNight
47%5%8%22%16%1
1599
21st to endNight
39%5%11%28%16%1
1544
May1st to 10thNight
47%6%12%22%12%1
1310
11th to 20thNight
39%7%9%25%16%4
1241
21st to endNight
45%5%9%24%15%
1357
June1st to 10thNight
44%7%12%21%15%1
1080
11th to 20thNight
48%9%13%19%10%
1080
21st to endNight
40%10%16%26%7%1
1080
July1st to 10thNight
36%10%15%27%12%
1050
11th to 20thNight
37%12%16%28%8%
1073
21st to endNight
42%9%18%27%5%
1302
August1st to 10thNight
32%9%22%30%7%
1358
11th to 20thNight
36%10%24%24%5%
1442
21st to endNight
45%8%20%21%5%
1782
September1st to 10thNight
40%8%19%24%8%1
1701
11th to 20thNight
46%8%16%26%3
1934
21st to endNight
45%7%15%27%6%
1980
October1st to 10thNight
54%7%13%22%4
2096
11th to 20thNight
56%8%17%16%3
2340
21st to endNight
69%7%9%12%3
2579
November1st to 10thNight
71%6%10%10%3
2662
11th to 20thNight
68%7%13%10%2
2850
21st to endNight
71%7%11%10%2
2850
December1st to 10thNight
69%7%11%11%3
2850
11th to 20thNight
61%6%13%14%5%
3735
21st to endNight
50%7%12%20%11%
5566

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
13%8%42%29%6%1
180
11th to 20thDay
11%6%44%31%8%1
228
21st to endDay
20%10%29%29%11%1
297
February1st to 10thDay
7%11%45%25%9%3
252
11th to 20thDay
11%12%35%27%13%2
240
21st to endDay
7%9%46%24%11%5%
198
March1st to 10thDay
14%9%38%25%12%2
240
11th to 20thDay
10%16%34%25%13%2
240
21st to endDay
12%14%39%25%8%2
358
April1st to 10thDay
14%13%37%28%8%1
478
11th to 20thDay
12%13%33%28%12%2
590
21st to endDay
14%14%30%28%12%1
600
May1st to 10thDay
21%11%35%23%8%1
603
11th to 20thDay
15%17%31%24%11%2
625
21st to endDay
21%11%31%24%11%2
679
June1st to 10thDay
20%15%27%22%14%3
630
11th to 20thDay
23%13%29%23%10%2
630
21st to endDay
19%10%28%26%14%3
630
July1st to 10thDay
15%12%27%29%13%4
621
11th to 20thDay
16%10%26%27%16%5%
618
21st to endDay
15%10%22%30%16%6%
684
August1st to 10thDay
13%10%29%29%14%5%
626
11th to 20thDay
13%11%30%26%16%4
615
21st to endDay
21%9%30%25%13%2
693
September1st to 10thDay
19%14%36%23%8%
546
11th to 20thDay
22%14%30%22%8%3
316
21st to endDay
22%14%30%25%8%1
270
October1st to 10thDay
23%17%30%22%5%2
270
11th to 20thDay
29%18%30%16%6%1
270
21st to endDay
25%12%32%21%9%1
297
November1st to 10thDay
18%9%34%28%10%1
270
11th to 20thDay
19%13%37%24%6%2
270
21st to endDay
21%13%40%21%32
270
December1st to 10thDay
9%11%36%28%13%3
270
11th to 20thDay
14%15%35%26%9%1
187
21st to endDay
9%8%29%37%14%3
198
January1st to 10thNight
13%9%37%32%8%2
950
11th to 20thNight
13%10%38%29%8%1
950
21st to endNight
18%10%35%28%8%1
1045
February1st to 10thNight
11%9%39%30%10%
923
11th to 20thNight
13%10%33%28%14%3
879
21st to endNight
7%11%35%30%16%1
660
March1st to 10thNight
12%8%28%34%16%1
720
11th to 20thNight
16%14%32%26%11%2
612
21st to endNight
12%9%32%27%17%3
594
April1st to 10thNight
16%6%29%35%13%1
540
11th to 20thNight
15%6%32%34%11%2
533
21st to endNight
11%10%35%33%10%1
540
May1st to 10thNight
20%8%34%28%10%1
540
11th to 20thNight
18%11%32%26%12%1
531
21st to endNight
20%9%31%30%10%1
583
June1st to 10thNight
19%8%28%31%13%1
360
11th to 20thNight
20%5%29%31%13%2
360
21st to endNight
17%7%21%37%17%1
360
July1st to 10thNight
13%6%26%33%21%
350
11th to 20thNight
12%6%26%36%16%4
377
21st to endNight
15%6%19%34%20%6%
591
August1st to 10thNight
11%7%27%30%22%3
537
11th to 20thNight
15%5%28%31%19%2
534
21st to endNight
20%7%28%33%12%1
594
September1st to 10thNight
19%9%29%30%13%
540
11th to 20thNight
20%8%27%34%10%1
540
21st to endNight
21%9%30%30%9%1
540
October1st to 10thNight
24%6%32%24%12%1
656
11th to 20thNight
25%10%28%28%9%1
900
21st to endNight
30%11%27%23%8%1
990
November1st to 10thNight
24%10%32%22%10%2
925
11th to 20thNight
20%12%35%23%10%1
950
21st to endNight
18%13%34%26%8%2
950
December1st to 10thNight
11%10%37%30%10%2
950
11th to 20thNight
16%10%33%26%11%3
950
21st to endNight
14%7%31%31%15%2
1045
Page generated at 2024-02-02 04:20:26. Version ac07

Copyright 2024 Attilla Danko


Snow Lake Clear Sky Chart |Charts Home