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Putman Mountain Observatory
.

Putman Mountain Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Putman Mountain Observatory clear sky chart from 2005-11-05 to 2017-05-24.

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
48%
15113
28%
45875
17%
15065
58%
15065
38%
25274

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
35%
900
29%
2327
11%
895
46%
895
37%
1418
January16th to endNight
34%
855
34%
2391
12%
855
51%
855
39%
1361
February1st to 15thNight
33%
704
29%
2107
12%
698
47%
698
34%
1180
February16th to endNight
24%
632
31%
1894
8%
632
43%
632
33%
1052
March1st to 15thNight
32%
593
29%
2033
13%
593
48%
593
29%
1124
March16th to endNight
32%
576
28%
2112
16%
576
49%
576
32%
1104
April1st to 15thNight
25%
539
25%
1968
9%
539
48%
539
31%
1057
April16th to endNight
28%
540
28%
1737
13%
540
50%
540
32%
993
May1st to 15thNight
31%
539
25%
1620
14%
539
47%
539
32%
955
May16th to endNight
44%
541
25%
1622
18%
540
57%
540
37%
923
June1st to 15thNight
61%
495
25%
1485
22%
495
70%
495
54%
714
June16th to endNight
63%
495
22%
1485
21%
495
69%
495
43%
797
July1st to 15thNight
75%
465
24%
1395
25%
465
78%
465
46%
734
July16th to endNight
84%
522
26%
1468
30%
489
87%
489
51%
734
August1st to 15thNight
88%
494
31%
1571
38%
491
89%
491
56%
713
August16th to endNight
79%
525
21%
1775
25%
525
80%
525
35%
977
September1st to 15thNight
76%
495
20%
1815
25%
495
77%
495
33%
1012
September16th to endNight
72%
492
26%
1815
26%
492
76%
492
32%
994
October1st to 15thNight
68%
495
36%
1815
33%
495
74%
495
42%
860
October16th to endNight
54%
685
36%
2093
21%
685
64%
685
47%
1052
November1st to 15thNight
50%
771
31%
2171
16%
771
58%
771
42%
1184
November16th to endNight
46%
900
32%
2340
15%
900
55%
900
42%
1344
December1st to 15thNight
39%
900
30%
2340
13%
900
48%
900
36%
1441
December16th to endNight
36%
960
26%
2496
11%
960
46%
960
34%
1551

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
9%42442445%7%51%
46394
Night
7%31332345%8%57%
46075
Cloud CoverDay
8%42442445%7%51%
46392
Night
7%31332345%8%57%
46075
TransparencyDay
33%5%9%20%21%10%
46092
Night
27%5%10%21%21%13%
45880
SeeingDay
11%6%22%35%20%4
4902
Night
9%6%31%36%14%1
15115

By Month

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
11%7%2332334454%
1611
16th to endDay
12%313313445%56%
1842
February1st to 15thDay
11%424223246%57%
1750
16th to endDay
10%422313345%55%
1580
March1st to 15thDay
13%423413337%50%
1926
16th to endDay
9%433413446%54%
2112
April1st to 15thDay
9%425%423348%50%
1977
16th to endDay
11%5%24424346%51%
2223
May1st to 15thDay
11%5%35%4346%6%7%42%
2331
16th to endDay
11%5%34335%5%6%7%42%
2336
June1st to 15thDay
33124245%6%9%56%
2145
16th to endDay
8%324436%5%6%10%45%
2145
July1st to 15thDay
6%425%5%35%5%5%9%46%
2145
16th to endDay
7%313435%5%5%10%49%
2284
August1st to 15thDay
211242345%10%62%
2046
16th to endDay
6%325%7%47%6%7%9%39%
2075
September1st to 15thDay
10%425%6%35%5%6%7%41%
1815
16th to endDay
8%424435%5%6%6%48%
1815
October1st to 15thDay
8%424413337%57%
1815
16th to endDay
6%21321223468%
1768
November1st to 15thDay
8%423423448%53%
1685
16th to endDay
9%424313225%60%
1620
December1st to 15thDay
15%5%14313345%51%
1620
16th to endDay
10%7%23423346%49%
1728
January1st to 15thNight
13%413223336%54%
2327
16th to endNight
12%312313436%56%
2391
February1st to 15thNight
9%5%2331224458%
2102
16th to endNight
9%312214348%57%
1894
March1st to 15thNight
11%31342435%8%51%
2033
16th to endNight
6%322324448%58%
2112
April1st to 15thNight
6%31332445%8%54%
1968
16th to endNight
6%323424449%55%
1737
May1st to 15thNight
7%4144235%5%8%52%
1619
16th to endNight
6%21331447%12%52%
1620
June1st to 15thNight
111222336%9%66%
1485
16th to endNight
41133235%6%8%58%
1485
July1st to 15thNight
421342346%11%57%
1485
16th to endNight
321232346%11%60%
1576
August1st to 15thNight
11121245%10%68%
1581
16th to endNight
5%314435%5%6%11%49%
1775
September1st to 15thNight
8%2233245%6%10%49%
1815
16th to endNight
8%2134345%5%8%52%
1815
October1st to 15thNight
6%22222447%64%
1815
16th to endNight
6%312213335%66%
2093
November1st to 15thNight
7%211313346%62%
2171
16th to endNight
7%312323236%62%
2340
December1st to 15thNight
12%41332435%6%52%
2340
16th to endNight
9%6%25%323436%53%
2496

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
11%7%2432333453%
1611
16th to endDay
12%314313345%56%
1842
February1st to 15thDay
12%413213346%57%
1750
16th to endDay
11%422313345%55%
1580
March1st to 15thDay
13%5%23423437%49%
1926
16th to endDay
9%5%24323445%54%
2110
April1st to 15thDay
9%5%24423347%50%
1977
16th to endDay
10%5%24424346%51%
2223
May1st to 15thDay
10%6%35%5%345%6%7%41%
2331
16th to endDay
10%5%35%425%5%5%7%43%
2336
June1st to 15thDay
32133335%6%10%55%
2145
16th to endDay
7%323446%5%6%10%44%
2145
July1st to 15thDay
6%325%5%36%5%6%8%46%
2145
16th to endDay
6%3135%26%45%10%49%
2284
August1st to 15thDay
211333346%9%60%
2046
16th to endDay
5%325%7%47%7%7%9%38%
2075
September1st to 15thDay
10%426%5%36%5%48%41%
1815
16th to endDay
8%324435%6%6%6%48%
1815
October1st to 15thDay
7%414413337%57%
1815
16th to endDay
6%312212235%68%
1768
November1st to 15thDay
8%42342245%7%53%
1685
16th to endDay
9%32442232460%
1620
December1st to 15thDay
15%5%24413246%51%
1620
16th to endDay
10%7%13423346%49%
1728
January1st to 15thNight
13%423323236%55%
2327
16th to endNight
11%412323346%56%
2391
February1st to 15thNight
9%5%23212235%58%
2102
16th to endNight
9%413213347%57%
1894
March1st to 15thNight
11%313324348%52%
2033
16th to endNight
6%31232445%7%58%
2112
April1st to 15thNight
5%32332445%8%55%
1968
16th to endNight
6%32342345%8%55%
1737
May1st to 15thNight
7%414424448%52%
1619
16th to endNight
6%21332347%12%52%
1620
June1st to 15thNight
111222335%9%66%
1485
16th to endNight
32233235%6%7%58%
1485
July1st to 15thNight
321332346%11%57%
1485
16th to endNight
321231336%11%60%
1576
August1st to 15thNight
11121245%9%68%
1581
16th to endNight
5%314435%5%5%11%49%
1775
September1st to 15thNight
8%313325%46%11%49%
1815
16th to endNight
7%3134345%5%7%53%
1815
October1st to 15thNight
6%21223347%64%
1815
16th to endNight
6%31221333466%
2093
November1st to 15thNight
7%212323337%62%
2171
16th to endNight
8%312323236%62%
2340
December1st to 15thNight
11%5%23324446%52%
2340
16th to endNight
8%6%25%323346%53%
2496

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
35%3318%26%13%
1612
16th to endDay
30%36%13%28%17%
1842
February1st to 15thDay
31%25%16%23%21%
1751
16th to endDay
31%3419%23%16%
1580
March1st to 15thDay
36%47%14%22%14%
1926
16th to endDay
33%48%18%22%12%
2112
April1st to 15thDay
34%5%8%15%21%15%
1977
16th to endDay
36%46%21%19%12%
2223
May1st to 15thDay
41%5%11%13%19%8%
2331
16th to endDay
40%7%8%17%20%4
2340
June1st to 15thDay
25%5%13%24%24%7%
2145
16th to endDay
35%8%12%22%16%5%
2145
July1st to 15thDay
35%7%11%27%15%2
2006
16th to endDay
27%6%21%29%13%1
2129
August1st to 15thDay
19%414%37%20%2
2032
16th to endDay
39%6%15%25%10%1
2075
September1st to 15thDay
41%6%11%20%16%4
1815
16th to endDay
35%5%10%17%20%9%
1815
October1st to 15thDay
30%49%19%24%12%
1815
16th to endDay
21%25%16%32%20%
1768
November1st to 15thDay
32%5%7%21%21%11%
1685
16th to endDay
29%25%15%21%24%
1620
December1st to 15thDay
37%36%17%23%11%
1620
16th to endDay
36%37%15%24%11%
1728
January1st to 15thNight
33%3418%21%19%
2327
16th to endNight
30%25%16%25%19%
2391
February1st to 15thNight
31%35%12%23%23%
2112
16th to endNight
29%4416%25%19%
1894
March1st to 15thNight
33%38%13%24%16%
2033
16th to endNight
28%5%10%20%21%13%
2112
April1st to 15thNight
30%49%18%19%17%
1968
16th to endNight
29%7%9%18%21%13%
1737
May1st to 15thNight
31%6%11%21%18%10%
1620
16th to endNight
27%7%14%26%19%4
1622
June1st to 15thNight
15%5%14%31%26%5%
1485
16th to endNight
24%6%15%31%17%4
1485
July1st to 15thNight
22%5%19%32%16%1
1395
16th to endNight
17%6%25%31%16%1
1468
August1st to 15thNight
13%6%19%37%22%1
1571
16th to endNight
28%6%23%26%12%2
1775
September1st to 15thNight
28%8%17%23%16%4
1815
16th to endNight
30%6%13%18%20%10%
1815
October1st to 15thNight
21%5%12%25%22%12%
1815
16th to endNight
22%25%16%28%22%
2093
November1st to 15thNight
25%46%25%24%14%
2171
16th to endNight
26%46%16%21%24%
2340
December1st to 15thNight
34%37%17%23%13%
2340
16th to endNight
34%36%15%23%15%
2496

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
13%14%36%26%8%
90
16th to endDay
15%9%45%22%6%
96
February1st to 15thDay
7%16%34%28%11%1
90
16th to endDay
13%9%40%29%6%
81
March1st to 15thDay
17%13%41%17%10%
90
16th to endDay
311%42%32%10%
96
April1st to 15thDay
13%18%34%28%5%
96
16th to endDay
12%15%42%21%7%
333
May1st to 15thDay
16%12%37%25%7%1
468
16th to endDay
17%9%32%28%11%1
481
June1st to 15thDay
3218%52%20%1
420
16th to endDay
9%115%44%25%4
420
July1st to 15thDay
6%211%49%28%2
400
16th to endDay
6%1342%36%9%
445
August1st to 15thDay
4242%39%10%
321
16th to endDay
10%26%39%32%7%
243
September1st to 15thDay
21324%46%22%
90
16th to endDay
5%221%54%16%
90
October1st to 15thDay
6%17%34%41%8%
90
16th to endDay
19%312%39%25%
96
November1st to 15thDay
30%8%24%23%8%4
90
16th to endDay
23%15%28%22%6%3
90
December1st to 15thDay
23%323%32%12%5%
90
16th to endDay
12%19%38%23%5%
96
January1st to 15thNight
15%8%36%30%7%
900
16th to endNight
14%8%40%30%6%
855
February1st to 15thNight
13%11%38%29%6%
704
16th to endNight
12%12%49%23%2
632
March1st to 15thNight
13%11%40%29%4
593
16th to endNight
8%12%46%29%3
576
April1st to 15thNight
7%12%52%25%2
539
16th to endNight
7%10%52%23%6%
540
May1st to 15thNight
9%11%44%29%5%
540
16th to endNight
7%5%40%33%12%
542
June1st to 15thNight
232%47%17%
495
16th to endNight
5%224%47%18%2
495
July1st to 15thNight
5%112%55%24%1
465
16th to endNight
45%60%26%2
522
August1st to 15thNight
2450%37%4
494
16th to endNight
6%8%48%32%3
525
September1st to 15thNight
10%7%42%32%5%
495
16th to endNight
9%11%41%34%2
492
October1st to 15thNight
8%218%44%25%1
495
16th to endNight
9%428%35%19%2
685
November1st to 15thNight
9%5%31%35%16%1
771
16th to endNight
10%9%30%36%11%1
900
December1st to 15thNight
15%8%34%33%7%
900
16th to endNight
13%10%35%32%7%
960
Page generated at 2017-05-25 12:27:32. Version ac04

Copyright 2017 A. Danko


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