Magazine Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Magazine Mountain clear sky chart from 2005-11-05 to 2019-06-10.

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
52%
18027
26%
54097
19%
17980
59%
17980
33%
31487

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
36%
1050
29%
2717
13%
1045
46%
1045
31%
1687
January16th to endNight
37%
1120
31%
2912
12%
1120
48%
1120
36%
1739
February1st to 15thNight
32%
1030
21%
2677
8%
1026
39%
1026
28%
1730
February16th to endNight
31%
684
26%
2154
11%
684
42%
684
26%
1290
March1st to 15thNight
39%
630
24%
2310
18%
630
48%
630
22%
1387
March16th to endNight
42%
672
20%
2464
18%
672
48%
672
24%
1488
April1st to 15thNight
42%
629
26%
2141
18%
629
55%
629
29%
1189
April16th to endNight
44%
624
23%
2078
17%
624
55%
624
30%
1199
May1st to 15thNight
53%
629
21%
1960
19%
629
60%
629
28%
1221
May16th to endNight
63%
659
21%
1973
21%
657
67%
657
36%
1155
June1st to 15thNight
76%
612
24%
1836
25%
612
79%
612
46%
961
June16th to endNight
79%
585
25%
1755
25%
585
81%
585
50%
882
July1st to 15thNight
76%
555
20%
1665
21%
555
78%
555
39%
938
July16th to endNight
85%
612
25%
1738
29%
579
86%
579
46%
911
August1st to 15thNight
77%
575
24%
1717
27%
572
78%
572
41%
944
August16th to endNight
76%
621
23%
2067
27%
621
77%
621
35%
1139
September1st to 15thNight
72%
585
27%
1953
30%
585
73%
585
34%
1084
September16th to endNight
69%
608
33%
2171
34%
608
72%
608
35%
1136
October1st to 15thNight
61%
780
30%
2340
24%
780
64%
780
38%
1305
October16th to endNight
55%
832
35%
2496
24%
832
64%
832
42%
1315
November1st to 15thNight
51%
820
30%
2460
22%
820
59%
820
35%
1414
November16th to endNight
45%
945
31%
2686
18%
945
55%
945
35%
1577
December1st to 15thNight
40%
1050
24%
2915
13%
1050
48%
1050
30%
1825
December16th to endNight
36%
1120
23%
2912
11%
1120
44%
1120
25%
1971

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%25%5%3445%7%44%
54391
Night
11%424423347%50%
54293
TransparencyDay
39%410%23%17%4
54091
Night
33%310%25%21%5%
54098
SeeingDay
13%6%20%26%24%9%
7960
Night
14%7%19%34%21%2
18028

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 15thDay
17%7%23223235%48%
1881
16th to endDay
12%6%25%41234450%
2016
February1st to 15thDay
16%7%35%333325%46%
1845
16th to endDay
18%8%26%5%23345%39%
1900
March1st to 15thDay
17%7%25%424245%45%
2310
16th to endDay
17%7%35%5%23346%38%
2462
April1st to 15thDay
14%5%25%434346%44%
2465
16th to endDay
17%6%25%5%33446%40%
2487
May1st to 15thDay
16%6%35%5%34445%39%
2648
16th to endDay
10%5%26%6%36%5%6%7%38%
2846
June1st to 15thDay
7%426%6%36%6%7%8%40%
2653
16th to endDay
6%3245%35%6%6%10%44%
2535
July1st to 15thDay
7%5%35%7%47%6%7%9%35%
2535
16th to endDay
5%3245%5%6%7%8%10%40%
2674
August1st to 15thDay
8%425%5%35%5%7%10%40%
2486
16th to endDay
8%4246%46%5%6%8%41%
2487
September1st to 15thDay
13%5%2443435%7%44%
2334
16th to endDay
9%5%1442445%6%49%
2106
October1st to 15thDay
13%5%26%424345%48%
1950
16th to endDay
13%413323345%56%
2080
November1st to 15thDay
11%5%24424345%51%
2058
16th to endDay
13%7%24313325%52%
1923
December1st to 15thDay
15%5%24423246%46%
1694
16th to endDay
17%7%34424235%43%
2016
January1st to 15thNight
15%5%23322235%51%
2717
16th to endNight
13%424422235%55%
2912
February1st to 15thNight
15%7%245%13345%46%
2668
16th to endNight
16%7%24322336%47%
2154
March1st to 15thNight
17%6%24324245%44%
2310
16th to endNight
16%5%25%423345%45%
2464
April1st to 15thNight
11%42442445%6%50%
2141
16th to endNight
11%5%24424446%49%
2078
May1st to 15thNight
12%425%434447%46%
1959
16th to endNight
7%5%2342446%9%47%
1971
June1st to 15thNight
421332346%8%58%
1836
16th to endNight
421221436%9%60%
1755
July1st to 15thNight
3424435%5%7%11%46%
1755
16th to endNight
32124345%8%11%53%
1846
August1st to 15thNight
43145%3346%10%51%
1727
16th to endNight
6%323435%6%7%10%47%
2067
September1st to 15thNight
10%41332335%6%52%
1953
16th to endNight
8%41442345%6%54%
2171
October1st to 15thNight
10%5%14323345%55%
2340
16th to endNight
12%31221224461%
2496
November1st to 15thNight
12%323314346%53%
2460
16th to endNight
13%5%24313235%54%
2686
December1st to 15thNight
16%6%24423336%47%
2915
16th to endNight
17%7%35%423335%43%
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
39%27%25%19%4
1882
16th to endDay
36%28%27%21%4
2016
February1st to 15thDay
42%310%24%16%3
1846
16th to endDay
47%27%20%16%5%
1900
March1st to 15thDay
42%28%20%17%8%
2310
16th to endDay
46%39%24%13%1
2464
April1st to 15thDay
40%310%22%18%4
2465
16th to endDay
43%47%21%19%2
2487
May1st to 15thDay
46%410%18%17%2
2648
16th to endDay
41%6%12%24%14%1
2850
June1st to 15thDay
37%7%12%25%16%
2653
16th to endDay
32%6%13%25%18%2
2535
July1st to 15thDay
40%7%14%27%9%1
2396
16th to endDay
33%7%15%28%13%
2519
August1st to 15thDay
36%6%13%24%16%2
2472
16th to endDay
37%5%16%21%14%3
2487
September1st to 15thDay
39%5%9%22%15%7%
2334
16th to endDay
32%49%23%24%5%
2106
October1st to 15thDay
37%38%21%22%7%
1950
16th to endDay
30%36%24%25%9%
2080
November1st to 15thDay
34%38%26%20%6%
2058
16th to endDay
36%27%22%26%5%
1923
December1st to 15thDay
39%210%23%19%4
1694
16th to endDay
44%28%23%17%4
2016
January1st to 15thNight
36%28%22%26%4
2717
16th to endNight
32%27%26%23%7%
2912
February1st to 15thNight
40%28%26%17%4
2678
16th to endNight
38%28%25%17%7%
2154
March1st to 15thNight
41%29%17%20%8%
2310
16th to endNight
42%28%25%17%3
2464
April1st to 15thNight
33%311%23%19%7%
2141
16th to endNight
34%39%24%23%4
2078
May1st to 15thNight
37%6%11%22%17%4
1960
16th to endNight
30%6%18%27%15%1
1973
June1st to 15thNight
22%5%12%33%24%2
1836
16th to endNight
20%414%29%26%5%
1755
July1st to 15thNight
27%6%18%28%16%1
1665
16th to endNight
21%6%17%34%18%1
1738
August1st to 15thNight
27%5%15%30%19%2
1717
16th to endNight
29%6%16%26%18%3
2067
September1st to 15thNight
31%49%25%20%7%
1953
16th to endNight
29%47%25%25%7%
2171
October1st to 15thNight
30%311%21%21%10%
2340
16th to endNight
27%26%22%30%12%
2496
November1st to 15thNight
31%38%24%22%9%
2460
16th to endNight
33%25%24%27%6%
2686
December1st to 15thNight
39%29%22%20%5%
2915
16th to endNight
44%27%22%16%4
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
25%9%36%20%8%
180
16th to endDay
13%19%33%22%9%1
192
February1st to 15thDay
15%20%38%17%7%1
180
16th to endDay
27%15%37%13%5%
159
March1st to 15thDay
21%20%36%21%
180
16th to endDay
15%19%38%18%7%1
192
April1st to 15thDay
18%18%27%22%13%1
344
16th to endDay
22%8%27%26%12%2
379
May1st to 15thDay
17%8%26%27%19%1
545
16th to endDay
11%6%24%31%18%7%
677
June1st to 15thDay
9%213%27%36%11%
616
16th to endDay
6%315%34%30%10%
570
July1st to 15thDay
6%112%29%32%17%
550
16th to endDay
45%25%41%23%
595
August1st to 15thDay
10%17%28%35%16%
549
16th to endDay
9%16%22%43%16%
399
September1st to 15thDay
11%18%17%40%21%
369
16th to endDay
11%18%33%31%13%
180
October1st to 15thDay
13%316%37%25%3
180
16th to endDay
16%8%25%29%15%5%
192
November1st to 15thDay
17%10%28%27%14%1
180
16th to endDay
22%12%22%21%16%3
180
December1st to 15thDay
17%10%40%17%11%2
180
16th to endDay
20%10%35%25%6%
192
January1st to 15thNight
20%12%24%34%7%
1050
16th to endNight
15%11%30%35%6%
1120
February1st to 15thNight
19%12%29%33%4
1030
16th to endNight
21%13%30%31%2
684
March1st to 15thNight
22%10%23%38%5%
630
16th to endNight
18%7%25%37%9%
672
April1st to 15thNight
13%10%28%34%11%
629
16th to endNight
14%8%27%36%13%
624
May1st to 15thNight
13%5%21%40%17%1
630
16th to endNight
10%416%37%27%4
659
June1st to 15thNight
418%36%43%3
612
16th to endNight
417%34%46%5%
585
July1st to 15thNight
317%29%49%8%
555
16th to endNight
4227%52%13%
612
August1st to 15thNight
6%428%49%9%
575
16th to endNight
8%1426%52%7%
621
September1st to 15thNight
12%6%26%47%5%
585
16th to endNight
10%19%33%38%6%
608
October1st to 15thNight
13%315%34%30%3
780
16th to endNight
13%6%20%34%23%1
832
November1st to 15thNight
12%8%20%38%18%
820
16th to endNight
17%9%22%34%15%
945
December1st to 15thNight
20%8%25%36%8%
1050
16th to endNight
22%11%21%37%6%
1120
Page generated at 2019-06-10 18:29:48. Version ac04

Copyright 2019 A. Danko


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