Massbach Ridge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Massbach Ridge clear sky chart from 2005-11-05 to 2017-04-01.

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
32%
15503
18%
45378
9%
15460
40%
15460
23%
29840

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
20%
900
14%
2506
4%
895
29%
895
18%
1806
January16th to endNight
16%
960
12%
2592
3%
960
23%
960
15%
1945
February1st to 15thNight
21%
871
15%
2283
3%
871
29%
871
19%
1601
February16th to endNight
21%
631
19%
1893
6%
631
32%
631
17%
1302
March1st to 15thNight
23%
686
15%
2126
7%
686
30%
686
18%
1409
March16th to endNight
23%
576
14%
2019
9%
576
32%
576
16%
1397
April1st to 15thNight
25%
497
19%
1657
11%
497
38%
497
20%
1071
April16th to endNight
31%
495
18%
1647
11%
495
42%
495
21%
1085
May1st to 15thNight
29%
495
16%
1370
7%
495
37%
495
22%
977
May16th to endNight
40%
515
18%
1369
8%
513
48%
513
32%
869
June1st to 15thNight
46%
495
17%
1320
9%
495
50%
495
34%
837
June16th to endNight
44%
495
16%
1320
7%
495
48%
495
33%
840
July1st to 15thNight
61%
465
21%
1240
12%
465
65%
465
45%
700
July16th to endNight
62%
522
23%
1305
15%
489
66%
489
45%
741
August1st to 15thNight
65%
494
24%
1443
21%
491
70%
491
43%
783
August16th to endNight
59%
525
20%
1750
21%
525
64%
525
34%
975
September1st to 15thNight
59%
495
28%
1650
26%
495
67%
495
37%
880
September16th to endNight
50%
610
26%
1768
15%
610
59%
610
34%
1028
October1st to 15thNight
37%
660
26%
1980
16%
660
47%
660
31%
1168
October16th to endNight
27%
704
19%
2184
8%
704
38%
704
22%
1400
November1st to 15thNight
30%
700
25%
2276
15%
700
43%
700
26%
1338
November16th to endNight
22%
852
17%
2472
7%
852
32%
852
19%
1691
December1st to 15thNight
17%
900
13%
2520
4%
900
24%
900
15%
1883
December16th to endNight
16%
960
12%
2688
2%
960
24%
960
12%
2114

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
15%8%36%5%3445%6%36%
45733
Night
14%8%35%5%24446%40%
45546
Cloud CoverDay
14%8%36%5%3445%7%36%
45741
Night
13%8%35%5%24446%40%
45551
TransparencyDay
47%312%22%11%1
45418
Night
44%312%23%14%1
45379
SeeingDay
17%11%30%23%12%4
5252
Night
18%11%30%27%10%1
15506

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%11%6%7%6%35%6%47%28%
1432
16th to endDay
12%14%7%11%6%33445%26%
1632
February1st to 15thDay
13%14%6%6%5%25%345%31%
1579
16th to endDay
14%11%37%6%3435%5%34%
1580
March1st to 15thDay
17%10%35%5%23447%36%
1835
16th to endDay
18%11%45%5%24445%31%
2205
April1st to 15thDay
18%10%45%5%34437%31%
1976
16th to endDay
23%9%25%434445%33%
1983
May1st to 15thDay
21%9%36%445%46%6%26%
2249
16th to endDay
14%6%35%6%35%45%6%36%
2393
June1st to 15thDay
15%435%6%36%5%5%7%34%
2310
16th to endDay
11%435%4346%6%9%40%
2310
July1st to 15thDay
7%3245%45%5%6%9%44%
2310
16th to endDay
8%5%26%5%46%6%6%10%38%
2459
August1st to 15thDay
7%425%6%35%5%8%9%41%
2173
16th to endDay
12%5%2433446%7%45%
2100
September1st to 15thDay
15%41442435%6%47%
1980
16th to endDay
12%6%24423447%45%
1848
October1st to 15thDay
17%6%25%33333446%
1650
16th to endDay
20%7%2442335%5%39%
1686
November1st to 15thDay
12%9%35%5%2445%5%40%
1582
16th to endDay
17%11%36%42322439%
1485
December1st to 15thDay
19%14%48%433335%29%
1440
16th to endDay
21%16%5%8%5%23335%24%
1536
January1st to 15thNight
13%10%5%8%5%3445%5%32%
2506
16th to endNight
11%12%6%9%7%35%446%28%
2592
February1st to 15thNight
12%11%5%6%6%23346%36%
2280
16th to endNight
14%11%37%434336%37%
1893
March1st to 15thNight
16%9%36%433345%38%
2113
16th to endNight
19%9%36%5%35%337%32%
2019
April1st to 15thNight
17%8%35%423346%38%
1657
16th to endNight
20%7%345%24337%37%
1647
May1st to 15thNight
17%6%34435%5%6%7%33%
1370
16th to endNight
11%5%24425%5%5%8%43%
1368
June1st to 15thNight
13%4235%235%6%7%44%
1320
16th to endNight
10%5%25%4346%6%9%42%
1320
July1st to 15thNight
7%31432435%9%56%
1320
16th to endNight
6%32242446%8%52%
1401
August1st to 15thNight
43145%235%6%8%54%
1452
16th to endNight
10%5%24324347%52%
1750
September1st to 15thNight
10%324413346%56%
1650
16th to endNight
8%4243245%5%8%50%
1768
October1st to 15thNight
12%5%24423346%50%
1980
16th to endNight
17%7%24423336%42%
2184
November1st to 15thNight
12%6%24423336%49%
2276
16th to endNight
18%7%36%424335%38%
2472
December1st to 15thNight
18%12%47%5%34435%29%
2520
16th to endNight
22%12%5%8%5%2444423%
2688

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%11%6%7%6%35%5%5%7%28%
1432
16th to endDay
12%13%7%11%6%24445%26%
1632
February1st to 15thDay
13%13%7%6%6%2434432%
1579
16th to endDay
14%11%47%6%25%35%5%34%
1580
March1st to 15thDay
15%11%35%5%23348%35%
1845
16th to endDay
17%11%46%5%34445%31%
2203
April1st to 15thDay
17%10%45%5%33447%31%
1976
16th to endDay
23%8%35%434445%32%
1983
May1st to 15thDay
20%9%36%5%45%46%6%26%
2249
16th to endDay
14%6%36%6%35%5%5%7%35%
2393
June1st to 15thDay
15%5%36%6%46%45%8%34%
2310
16th to endDay
10%5%25%435%6%6%9%40%
2310
July1st to 15thDay
6%4245%45%5%6%9%44%
2310
16th to endDay
8%5%26%5%46%6%6%10%38%
2459
August1st to 15thDay
6%425%6%45%6%7%10%40%
2173
16th to endDay
12%42443446%7%44%
2100
September1st to 15thDay
14%4144245%46%47%
1980
16th to endDay
12%6%24423448%45%
1848
October1st to 15thDay
16%6%25%42333446%
1650
16th to endDay
19%7%35%423346%38%
1686
November1st to 15thDay
11%9%36%5%3445%5%40%
1582
16th to endDay
17%11%45%42323438%
1485
December1st to 15thDay
19%13%47%433345%28%
1440
16th to endDay
21%15%6%8%5%23335%24%
1536
January1st to 15thNight
13%11%48%5%3445%5%32%
2506
16th to endNight
11%12%6%9%7%35%35%6%27%
2592
February1st to 15thNight
12%11%5%7%5%23345%36%
2273
16th to endNight
14%11%46%5%34336%36%
1893
March1st to 15thNight
16%9%35%5%33345%38%
2126
16th to endNight
18%10%46%5%35%337%32%
2019
April1st to 15thNight
17%8%4442335%6%38%
1657
16th to endNight
19%7%35%5%24437%36%
1647
May1st to 15thNight
17%5%345%35%6%6%7%33%
1369
16th to endNight
11%5%24425%46%8%43%
1368
June1st to 15thNight
12%5%1442447%8%44%
1320
16th to endNight
10%6%24435%5%6%8%42%
1320
July1st to 15thNight
6%31331435%9%55%
1320
16th to endNight
5%3234245%6%9%52%
1401
August1st to 15thNight
43144335%5%9%53%
1452
16th to endNight
9%5%14424347%51%
1750
September1st to 15thNight
9%424313346%55%
1650
16th to endNight
7%424425%45%8%50%
1768
October1st to 15thNight
11%6%24423246%50%
1980
16th to endNight
16%7%24424346%41%
2184
November1st to 15thNight
12%6%24423346%48%
2276
16th to endNight
18%8%36%434345%38%
2472
December1st to 15thNight
18%11%47%6%34445%29%
2520
16th to endNight
22%12%5%8%5%3444423%
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
54%315%16%10%
1433
16th to endDay
59%313%15%7%
1632
February1st to 15thDay
56%212%20%7%1
1580
16th to endDay
52%311%22%9%1
1580
March1st to 15thDay
47%316%21%9%1
1845
16th to endDay
54%312%20%7%1
2205
April1st to 15thDay
52%39%23%9%
1976
16th to endDay
54%310%17%11%2
1983
May1st to 15thDay
56%312%19%7%
2249
16th to endDay
47%411%20%14%1
2397
June1st to 15thDay
46%5%12%22%12%
2310
16th to endDay
38%413%25%15%1
2310
July1st to 15thDay
35%415%27%15%1
2161
16th to endDay
38%5%16%22%12%2
2292
August1st to 15thDay
36%5%13%28%15%1
2158
16th to endDay
36%411%28%15%2
2100
September1st to 15thDay
36%48%29%20%1
1980
16th to endDay
37%311%29%16%1
1848
October1st to 15thDay
41%29%28%16%
1650
16th to endDay
46%212%25%11%1
1686
November1st to 15thDay
44%311%25%12%2
1582
16th to endDay
50%218%22%5%
1485
December1st to 15thDay
58%214%16%6%
1440
16th to endDay
63%213%10%8%
1536
January1st to 15thNight
51%313%18%12%
2506
16th to endNight
56%314%16%8%
2592
February1st to 15thNight
50%112%23%11%1
2283
16th to endNight
49%312%23%8%2
1893
March1st to 15thNight
48%213%21%12%1
2126
16th to endNight
53%212%21%8%1
2019
April1st to 15thNight
46%29%23%15%1
1657
16th to endNight
48%210%22%13%3
1647
May1st to 15thNight
47%6%13%19%11%
1370
16th to endNight
36%5%14%23%17%2
1370
June1st to 15thNight
35%412%26%19%
1320
16th to endNight
37%411%21%19%4
1320
July1st to 15thNight
26%312%34%18%3
1240
16th to endNight
26%417%32%17%2
1305
August1st to 15thNight
27%313%32%20%2
1443
16th to endNight
33%311%28%19%4
1750
September1st to 15thNight
30%29%28%27%1
1650
16th to endNight
32%311%32%18%2
1768
October1st to 15thNight
35%29%26%22%2
1980
16th to endNight
44%211%27%12%1
2184
November1st to 15thNight
37%211%25%19%3
2276
16th to endNight
48%312%25%10%
2472
December1st to 15thNight
57%310%20%7%
2520
16th to endNight
63%211%13%6%1
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
22%25%36%13%2
90
16th to endDay
27%16%37%10%8%
96
February1st to 15thDay
20%40%24%10%5%
90
16th to endDay
27%25%33%9%21
81
March1st to 15thDay
31%27%30%7%21
90
16th to endDay
28%14%31%17%5%2
189
April1st to 15thDay
25%16%29%19%8%
212
16th to endDay
25%11%27%21%11%2
210
May1st to 15thDay
25%15%31%16%7%2
341
16th to endDay
15%13%32%26%8%4
437
June1st to 15thDay
15%10%36%22%11%3
420
16th to endDay
13%7%35%25%13%4
420
July1st to 15thDay
9%6%30%28%16%9%
400
16th to endDay
10%5%29%29%17%7%
445
August1st to 15thDay
6%226%35%22%6%
405
16th to endDay
13%5%21%27%23%8%
268
September1st to 15thDay
13%427%23%20%9%
255
16th to endDay
11%9%27%29%15%6%
251
October1st to 15thDay
16%14%32%24%11%1
90
16th to endDay
27%19%33%17%2
96
November1st to 15thDay
5%23%27%32%5%5%
90
16th to endDay
42%15%34%34
90
December1st to 15thDay
26%25%30%14%3
90
16th to endDay
33%30%33%3
96
January1st to 15thNight
20%18%35%20%5%
900
16th to endNight
17%17%37%22%3
960
February1st to 15thNight
19%17%33%23%4
874
16th to endNight
19%19%35%19%5%
631
March1st to 15thNight
21%14%33%22%6%
686
16th to endNight
22%14%32%21%7%1
576
April1st to 15thNight
21%16%30%25%5%
497
16th to endNight
24%8%31%27%8%1
495
May1st to 15thNight
19%8%36%26%9%
495
16th to endNight
14%5%32%34%12%
515
June1st to 15thNight
13%5%29%42%9%
495
16th to endNight
13%330%37%14%
495
July1st to 15thNight
9%221%40%23%3
465
16th to endNight
7%221%41%25%1
522
August1st to 15thNight
4117%42%29%3
494
16th to endNight
11%18%39%25%4
525
September1st to 15thNight
10%419%36%21%6%
495
16th to endNight
11%8%23%30%21%3
610
October1st to 15thNight
13%10%32%25%15%1
660
16th to endNight
21%14%31%22%9%
704
November1st to 15thNight
16%15%33%26%8%
700
16th to endNight
22%16%33%19%7%
852
December1st to 15thNight
24%16%34%18%4
900
16th to endNight
27%15%31%21%3
960
Page generated at 2017-04-02 06:39:07. Version ac04

Copyright 2017 A. Danko


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