Scranton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Scranton clear sky chart from 2005-11-05 to 2018-01-20.

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
30%
15476
16%
48494
9%
15444
38%
15444
18%
32975

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
16%
780
13%
2716
6%
776
25%
776
10%
1997
January16th to endNight
13%
788
14%
2615
4%
788
25%
788
12%
1875
February1st to 15thNight
9%
704
12%
2287
2%
701
22%
701
10%
1690
February16th to endNight
14%
631
16%
1896
5%
631
27%
631
12%
1379
March1st to 15thNight
17%
720
15%
2087
6%
720
28%
720
15%
1505
March16th to endNight
20%
768
19%
2037
7%
768
30%
768
19%
1428
April1st to 15thNight
19%
718
14%
1796
4%
718
25%
718
18%
1324
April16th to endNight
28%
720
17%
1800
4%
720
34%
720
25%
1231
May1st to 15thNight
32%
444
18%
1524
10%
444
42%
444
18%
1014
May16th to endNight
41%
374
15%
1497
13%
374
48%
374
18%
940
June1st to 15thNight
43%
360
14%
1440
13%
360
51%
360
19%
914
June16th to endNight
54%
360
15%
1440
16%
360
62%
360
27%
807
July1st to 15thNight
55%
340
13%
1360
17%
340
60%
340
24%
799
July16th to endNight
58%
382
17%
1424
18%
360
63%
360
26%
800
August1st to 15thNight
59%
546
16%
1616
12%
543
62%
543
30%
997
August16th to endNight
57%
764
20%
1910
11%
764
59%
764
34%
1246
September1st to 15thNight
46%
720
20%
1800
11%
720
50%
720
31%
1199
September16th to endNight
50%
717
27%
1947
19%
717
56%
717
33%
1215
October1st to 15thNight
41%
720
20%
2160
16%
720
48%
720
24%
1376
October16th to endNight
28%
768
18%
2351
9%
768
39%
768
20%
1565
November1st to 15thNight
26%
760
17%
2472
9%
760
37%
760
19%
1654
November16th to endNight
24%
780
17%
2677
9%
780
36%
780
15%
1808
December1st to 15thNight
17%
780
10%
2730
4%
780
25%
780
10%
2012
December16th to endNight
14%
832
10%
2912
2%
832
24%
832
9%
2200

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%6%35%45%7%32%
49038
Night
14%8%36%5%3445%6%35%
48664
Cloud CoverDay
15%8%36%6%35%45%7%32%
49047
Night
14%8%36%5%35%45%6%36%
48670
TransparencyDay
50%5%11%20%11%1
48726
Night
47%5%12%21%11%1
48494
SeeingDay
22%15%25%19%11%4
6011
Night
21%15%27%24%10%1
15477

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
14%8%6%11%7%45%445%28%
1552
16th to endDay
11%11%5%9%9%35%5%5%6%25%
1710
February1st to 15thDay
14%12%5%10%7%45%446%23%
1575
16th to endDay
14%11%48%7%35%446%28%
1577
March1st to 15thDay
15%11%6%7%7%35%447%27%
1862
16th to endDay
16%9%5%7%6%33447%32%
2187
April1st to 15thDay
19%10%44434445%34%
2152
16th to endDay
14%8%35%5%3445%6%38%
2160
May1st to 15thDay
20%7%25%5%35%446%32%
2433
16th to endDay
16%7%25%5%35%45%7%33%
2618
June1st to 15thDay
17%5%35%6%36%5%5%9%29%
2520
16th to endDay
15%6%35%5%35%46%9%32%
2520
July1st to 15thDay
12%6%26%7%46%5%7%9%32%
2520
16th to endDay
10%5%25%6%46%5%7%9%36%
2647
August1st to 15thDay
14%7%25%6%45%6%6%8%30%
2319
16th to endDay
13%6%26%5%3446%7%37%
2292
September1st to 15thDay
17%5%25%5%3445%6%37%
2160
16th to endDay
13%5%25%43436%6%44%
2010
October1st to 15thDay
16%7%36%5%33447%36%
1800
16th to endDay
19%9%35%5%25%45%7%30%
1872
November1st to 15thDay
15%11%36%5%24445%36%
1716
16th to endDay
16%9%26%5%2445%6%35%
1612
December1st to 15thDay
17%12%5%6%7%3445%6%26%
1560
16th to endDay
15%14%6%9%6%35%5%6%5%21%
1664
January1st to 15thNight
14%9%5%9%8%45%45%6%26%
2716
16th to endNight
12%11%5%8%7%45%5%5%6%27%
2615
February1st to 15thNight
14%11%5%9%6%35%5%46%28%
2285
16th to endNight
12%11%48%7%36%5%45%29%
1896
March1st to 15thNight
15%9%47%5%35%45%6%31%
2074
16th to endNight
16%9%45%434445%37%
2037
April1st to 15thNight
17%9%36%6%24446%33%
1796
16th to endNight
17%6%24423446%43%
1800
May1st to 15thNight
17%6%35%5%35%45%6%37%
1524
16th to endNight
11%7%36%5%35%5%5%7%37%
1495
June1st to 15thNight
18%5%35%42445%7%37%
1440
16th to endNight
10%415%4245%6%10%45%
1440
July1st to 15thNight
10%434436%5%5%9%41%
1440
16th to endNight
9%424436%5%5%9%45%
1520
August1st to 15thNight
9%5%25%5%35%6%6%8%42%
1627
16th to endNight
11%4245%2445%8%45%
1910
September1st to 15thNight
15%434325%446%44%
1800
16th to endNight
12%5%245%33446%47%
1947
October1st to 15thNight
17%6%25%424346%42%
2160
16th to endNight
19%7%25%42445%5%38%
2351
November1st to 15thNight
14%10%36%5%2335%5%38%
2472
16th to endNight
14%9%36%5%2446%6%34%
2677
December1st to 15thNight
18%11%48%5%345%5%6%25%
2730
16th to endNight
17%11%5%9%6%35%446%24%
2912

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
13%9%5%11%7%35%335%29%
1552
16th to endDay
11%11%5%10%9%445%46%25%
1710
February1st to 15thDay
15%12%5%9%8%46%446%22%
1575
16th to endDay
14%11%49%6%35%436%28%
1577
March1st to 15thDay
16%10%5%7%6%35%447%27%
1872
16th to endDay
16%9%47%6%34346%32%
2186
April1st to 15thDay
18%10%45%424445%35%
2152
16th to endDay
14%8%25%5%3346%6%38%
2160
May1st to 15thDay
20%7%26%6%35%45%6%32%
2433
16th to endDay
16%7%35%5%35%5%5%7%33%
2618
June1st to 15thDay
18%5%36%5%35%45%9%30%
2520
16th to endDay
16%6%25%5%45%5%6%8%33%
2520
July1st to 15thDay
12%5%26%7%36%5%7%9%33%
2520
16th to endDay
10%5%26%5%36%5%7%9%36%
2647
August1st to 15thDay
14%7%25%6%46%5%6%8%30%
2319
16th to endDay
13%6%35%5%4446%7%37%
2292
September1st to 15thDay
16%6%25%6%34447%37%
2160
16th to endDay
13%5%245%2445%6%44%
2010
October1st to 15thDay
15%7%35%5%3345%7%37%
1800
16th to endDay
19%8%46%5%35%447%31%
1872
November1st to 15thDay
15%11%36%5%23346%36%
1716
16th to endDay
16%9%37%5%3445%6%35%
1612
December1st to 15thDay
16%11%5%7%7%3435%6%27%
1560
16th to endDay
15%13%6%10%6%35%46%5%21%
1664
January1st to 15thNight
13%10%5%9%7%45%5%46%26%
2716
16th to endNight
12%10%48%8%35%5%5%6%28%
2615
February1st to 15thNight
13%11%5%8%6%35%445%29%
2278
16th to endNight
12%12%48%7%36%5%45%29%
1896
March1st to 15thNight
15%10%48%5%25%446%31%
2087
16th to endNight
16%9%45%424446%37%
2037
April1st to 15thNight
17%9%46%6%34446%33%
1796
16th to endNight
17%5%25%424346%42%
1800
May1st to 15thNight
16%6%25%5%36%45%6%37%
1524
16th to endNight
11%7%36%6%35%5%5%8%37%
1495
June1st to 15thNight
18%5%25%5%25%45%6%38%
1440
16th to endNight
10%42443446%9%45%
1440
July1st to 15thNight
10%424435%5%6%8%42%
1440
16th to endNight
10%4234345%5%9%45%
1520
August1st to 15thNight
9%6%15%4347%5%9%42%
1627
16th to endNight
11%325%425%45%8%45%
1910
September1st to 15thNight
15%5%2432445%5%45%
1800
16th to endNight
12%4245%2345%6%47%
1947
October1st to 15thNight
16%5%25%32435%6%42%
2160
16th to endNight
19%7%2432445%6%38%
2351
November1st to 15thNight
14%10%36%5%23345%38%
2472
16th to endNight
13%9%46%5%35%45%7%35%
2677
December1st to 15thNight
17%12%47%6%35%45%7%25%
2730
16th to endNight
16%11%6%9%6%36%446%24%
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
57%49%18%7%2
1553
16th to endDay
58%311%17%8%
1710
February1st to 15thDay
61%48%15%8%
1577
16th to endDay
57%5%9%20%7%
1577
March1st to 15thDay
56%413%17%7%1
1872
16th to endDay
52%38%19%13%1
2187
April1st to 15thDay
51%48%21%10%2
2152
16th to endDay
44%38%23%17%2
2160
May1st to 15thDay
51%5%8%21%11%1
2433
16th to endDay
49%6%13%17%13%
2622
June1st to 15thDay
50%5%13%21%9%
2520
16th to endDay
46%6%13%23%9%
2520
July1st to 15thDay
46%5%12%20%13%1
2371
16th to endDay
40%5%14%23%13%1
2480
August1st to 15thDay
48%6%12%21%10%
2306
16th to endDay
44%410%24%15%1
2292
September1st to 15thDay
46%410%21%16%
2160
16th to endDay
38%410%24%20%2
2010
October1st to 15thDay
45%5%11%20%14%1
1800
16th to endDay
52%412%21%9%
1872
November1st to 15thDay
49%412%19%12%2
1716
16th to endDay
49%311%23%11%
1612
December1st to 15thDay
57%415%14%6%
1560
16th to endDay
61%5%13%13%5%
1664
January1st to 15thNight
56%6%10%16%7%1
2716
16th to endNight
54%412%19%8%
2615
February1st to 15thNight
55%6%12%16%8%
2287
16th to endNight
55%49%20%9%1
1896
March1st to 15thNight
53%313%18%10%1
2087
16th to endNight
48%411%19%13%2
2037
April1st to 15thNight
51%49%19%13%1
1796
16th to endNight
42%49%22%18%1
1800
May1st to 15thNight
46%5%10%21%13%1
1524
16th to endNight
43%6%13%21%11%2
1497
June1st to 15thNight
44%5%13%25%10%
1440
16th to endNight
34%5%18%28%12%
1440
July1st to 15thNight
36%7%14%26%13%1
1360
16th to endNight
33%7%16%27%12%2
1424
August1st to 15thNight
35%6%15%27%13%
1616
16th to endNight
36%6%12%25%18%1
1910
September1st to 15thNight
39%412%25%16%1
1800
16th to endNight
36%48%27%22%1
1947
October1st to 15thNight
41%411%24%15%1
2160
16th to endNight
45%415%24%10%
2351
November1st to 15thNight
47%412%19%12%3
2472
16th to endNight
49%413%21%11%
2677
December1st to 15thNight
57%5%13%16%6%
2730
16th to endNight
60%5%12%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
36%32%21%6%21
90
16th to endDay
34%26%27%10%2
96
February1st to 15thDay
30%42%23%4
90
16th to endDay
22%30%31%11%3
236
March1st to 15thDay
26%22%30%15%4
270
16th to endDay
25%26%23%15%6%2
288
April1st to 15thDay
29%20%28%13%5%1
270
16th to endDay
19%18%31%16%10%4
270
May1st to 15thDay
37%14%22%11%9%4
288
16th to endDay
19%12%30%21%12%3
331
June1st to 15thDay
22%13%24%24%11%3
315
16th to endDay
23%10%28%26%9%
315
July1st to 15thDay
19%5%29%25%15%3
305
16th to endDay
12%6%26%33%16%5%
326
August1st to 15thDay
17%7%24%22%19%8%
313
16th to endDay
12%6%22%26%19%13%
332
September1st to 15thDay
17%12%22%18%18%12%
315
16th to endDay
16%6%22%20%20%14%
314
October1st to 15thDay
20%9%21%25%17%5%
315
16th to endDay
25%20%26%17%8%
324
November1st to 15thDay
24%16%23%23%10%1
280
16th to endDay
26%26%25%19%2
142
December1st to 15thDay
25%32%24%10%6%1
90
16th to endDay
35%32%30%2
96
January1st to 15thNight
22%25%31%16%3
780
16th to endNight
23%24%34%15%1
788
February1st to 15thNight
26%24%33%14%
704
16th to endNight
24%27%29%15%1
631
March1st to 15thNight
28%21%30%17%2
720
16th to endNight
25%19%30%17%7%
768
April1st to 15thNight
26%20%29%20%2
718
16th to endNight
23%14%29%23%9%
720
May1st to 15thNight
22%12%27%26%9%
444
16th to endNight
12%7%29%35%14%
375
June1st to 15thNight
20%7%20%36%14%
360
16th to endNight
11%225%50%10%
360
July1st to 15thNight
13%322%41%18%
340
16th to endNight
12%417%42%20%2
382
August1st to 15thNight
12%117%42%21%3
546
16th to endNight
14%315%33%30%1
764
September1st to 15thNight
17%6%23%31%18%2
720
16th to endNight
16%6%19%26%25%6%
717
October1st to 15thNight
20%10%22%29%17%
720
16th to endNight
25%15%28%24%6%
768
November1st to 15thNight
20%18%30%22%8%1
760
16th to endNight
21%20%28%20%6%1
780
December1st to 15thNight
27%21%29%16%4
780
16th to endNight
27%24%31%14%2
832
Page generated at 2018-01-21 12:19:32. Version ac04

Copyright 2018 A. Danko


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