Glens Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Glens Falls clear sky chart from 2005-11-06 to 2024-01-12.

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%
22792
14%
74691
9%
22752
39%
22752
17%
52184

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
21%
760
12%
2649
6%
757
30%
757
12%
1918
January11th to 20thNight
21%
725
9%
2535
4%
725
27%
725
10%
1920
January21st to endNight
23%
792
12%
2743
7%
792
32%
792
15%
1930
February1st to 10thNight
16%
720
9%
2340
3%
720
22%
720
10%
1797
February11th to 20thNight
18%
703
13%
2131
4%
700
30%
700
14%
1554
February21st to endNight
20%
592
14%
1776
7%
592
30%
592
15%
1293
March1st to 10thNight
23%
720
16%
2160
9%
720
32%
720
16%
1573
March11th to 20thNight
23%
720
14%
2094
7%
720
31%
720
16%
1500
March21st to endNight
24%
792
20%
1980
6%
792
33%
792
21%
1426
April1st to 10thNight
24%
720
15%
1800
4%
720
30%
720
20%
1321
April11th to 20thNight
26%
711
15%
1775
5%
711
31%
711
22%
1287
April21st to endNight
27%
617
16%
1697
5%
617
34%
617
19%
1211
May1st to 10thNight
29%
500
13%
1580
8%
500
34%
500
15%
1146
May11th to 20thNight
31%
354
17%
1416
13%
354
43%
354
17%
921
May21st to endNight
45%
388
13%
1551
15%
388
50%
388
19%
973
June1st to 10thNight
43%
360
14%
1440
15%
360
51%
360
18%
938
June11th to 20thNight
43%
360
12%
1440
14%
360
50%
360
19%
901
June21st to endNight
46%
360
12%
1440
14%
360
52%
360
19%
921
July1st to 10thNight
55%
350
13%
1400
18%
350
59%
350
21%
843
July11th to 20thNight
56%
348
14%
1392
18%
348
59%
348
23%
838
July21st to endNight
57%
394
17%
1486
20%
372
62%
372
24%
877
August1st to 10thNight
59%
358
17%
1422
18%
356
63%
356
26%
814
August11th to 20thNight
54%
658
14%
1722
10%
658
56%
658
27%
1179
August21st to endNight
55%
792
18%
1980
9%
792
57%
792
32%
1323
September1st to 10thNight
52%
720
17%
1800
8%
720
55%
720
32%
1211
September11th to 20thNight
51%
720
23%
1885
14%
720
55%
720
34%
1183
September21st to endNight
46%
720
22%
1980
16%
720
51%
720
29%
1292
October1st to 10thNight
36%
720
14%
2074
10%
720
42%
720
19%
1497
October11th to 20thNight
36%
720
15%
2168
10%
720
43%
720
21%
1506
October21st to endNight
27%
792
12%
2574
8%
792
35%
792
14%
1895
November1st to 10thNight
31%
740
17%
2407
12%
740
39%
740
20%
1596
November11th to 20thNight
29%
760
18%
2470
11%
760
38%
760
19%
1670
November21st to endNight
26%
760
13%
2632
7%
760
35%
760
16%
1819
December1st to 10thNight
21%
760
10%
2660
5%
760
28%
760
11%
2013
December11th to 20thNight
24%
759
11%
3241
5%
759
32%
759
10%
2347
December21st to endNight
19%
827
6%
4851
3%
817
26%
817
6%
3751

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
16%8%36%6%35%5%5%7%35%
74757
Night
17%9%36%6%345%5%6%35%
74942
TransparencyDay
47%8%13%19%11%1
74462
Night
48%8%13%19%10%1
74771
SeeingDay
21%15%30%22%10%3
13655
Night
20%11%30%29%9%1
22803

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 10thDay
14%12%49%6%45%5%7%6%28%
1517
11th to 20thDay
15%13%46%7%36%6%5%6%28%
1448
21st to endDay
11%10%5%9%8%5%6%6%5%7%29%
1611
February1st to 10thDay
14%13%48%7%46%5%6%7%26%
1620
11th to 20thDay
13%12%6%9%6%35%5%6%6%29%
1716
21st to endDay
19%11%5%7%6%3445%5%31%
1480
March1st to 10thDay
14%7%5%10%7%35%45%8%34%
1797
11th to 20thDay
17%10%47%5%35%35%6%34%
1862
21st to endDay
17%10%47%6%34435%38%
2376
April1st to 10thDay
18%9%46%5%3445%6%36%
2160
11th to 20thDay
16%6%37%7%345%5%6%38%
2134
21st to endDay
21%8%46%6%445%5%6%32%
2261
May1st to 10thDay
22%8%37%5%2446%6%33%
2395
11th to 20thDay
17%6%36%5%346%5%6%38%
2478
21st to endDay
14%6%36%5%35%5%6%8%39%
2725
June1st to 10thDay
16%6%36%7%46%6%7%8%31%
2520
11th to 20thDay
17%6%35%5%45%6%6%9%36%
2520
21st to endDay
16%6%37%7%36%6%5%9%32%
2520
July1st to 10thDay
12%5%36%5%45%6%7%8%39%
2520
11th to 20thDay
11%6%35%6%45%6%8%10%37%
2520
21st to endDay
13%5%36%6%46%7%6%9%35%
2744
August1st to 10thDay
11%5%25%7%46%6%7%10%38%
2506
11th to 20thDay
12%6%35%6%46%6%8%10%34%
2157
21st to endDay
12%5%36%5%45%6%5%8%42%
2376
September1st to 10thDay
13%425%436%5%6%8%44%
2160
11th to 20thDay
15%5%244335%5%7%48%
2074
21st to endDay
15%5%35%5%25%5%5%8%43%
1980
October1st to 10thDay
21%9%27%6%445%5%5%34%
1883
11th to 20thDay
15%8%26%6%445%6%8%37%
1792
21st to endDay
25%8%36%6%45%45%6%28%
1782
November1st to 10thDay
13%8%37%5%345%6%7%39%
1671
11th to 20thDay
17%8%45%5%26%6%5%6%35%
1710
21st to endDay
19%7%47%6%35%5%5%7%33%
1544
December1st to 10thDay
20%12%6%9%6%445%48%24%
1520
11th to 20thDay
22%10%37%6%35%435%31%
1906
21st to endDay
26%17%5%7%6%2433423%
2772
January1st to 10thNight
15%11%5%8%6%4445%6%31%
2649
11th to 20thNight
17%13%48%6%4445%6%27%
2535
21st to endNight
11%11%49%6%36%6%5%6%33%
2743
February1st to 10thNight
14%12%5%9%8%47%5%5%6%25%
2340
11th to 20thNight
12%10%5%8%7%45%6%6%6%32%
2129
21st to endNight
16%9%48%7%35%5%5%5%32%
1776
March1st to 10thNight
15%10%47%6%45%6%5%5%34%
2150
11th to 20thNight
18%9%5%6%5%345%45%36%
2093
21st to endNight
17%9%36%5%34446%39%
1980
April1st to 10thNight
20%6%46%6%35%446%37%
1800
11th to 20thNight
19%8%35%5%4435%7%37%
1775
21st to endNight
20%9%26%5%345%5%6%37%
1697
May1st to 10thNight
21%9%37%6%33446%32%
1580
11th to 20thNight
19%8%34434447%39%
1415
21st to endNight
14%5%36%6%35%6%48%41%
1550
June1st to 10thNight
19%5%25%5%45%6%7%6%37%
1440
11th to 20thNight
17%6%36%43436%8%40%
1440
21st to endNight
15%435%5%445%6%7%40%
1440
July1st to 10thNight
13%5%35%5%36%5%6%8%42%
1440
11th to 20thNight
12%5%26%5%35%5%5%10%42%
1440
21st to endNight
11%5%35%5%5%446%9%44%
1574
August1st to 10thNight
11%5%245%345%6%10%46%
1432
11th to 20thNight
13%5%26%6%35%6%7%9%38%
1722
21st to endNight
15%5%244245%6%8%45%
1980
September1st to 10thNight
13%5%25%5%345%6%7%45%
1800
11th to 20thNight
14%5%25%323447%51%
1885
21st to endNight
15%425%435%46%6%46%
1980
October1st to 10thNight
20%8%36%6%445%5%5%34%
2074
11th to 20thNight
16%7%36%7%45%5%6%6%37%
2168
21st to endNight
25%7%36%6%3445%6%30%
2574
November1st to 10thNight
14%8%37%5%45%446%40%
2407
11th to 20thNight
19%7%35%5%2446%6%39%
2470
21st to endNight
16%9%36%6%345%5%7%35%
2632
December1st to 10thNight
20%12%5%7%6%35%446%27%
2660
11th to 20thNight
23%9%36%6%35%45%6%30%
3288
21st to endNight
26%16%5%6%5%34435%23%
4884

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
53%8%13%18%7%
1518
11th to 20thDay
55%8%13%13%8%2
1448
21st to endDay
54%6%14%15%8%2
1611
February1st to 10thDay
57%9%14%14%6%1
1620
11th to 20thDay
57%6%12%15%9%1
1725
21st to endDay
56%6%12%14%11%1
1480
March1st to 10thDay
50%7%13%17%10%2
1800
11th to 20thDay
51%7%12%13%14%3
1862
21st to endDay
51%5%8%18%14%4
2376
April1st to 10thDay
49%6%10%20%11%3
2160
11th to 20thDay
46%8%10%19%15%2
2134
21st to endDay
51%8%10%16%11%3
2261
May1st to 10thDay
51%7%9%18%13%2
2395
11th to 20thDay
44%7%12%19%16%2
2482
21st to endDay
42%9%16%21%11%1
2725
June1st to 10thDay
47%10%15%17%9%1
2520
11th to 20thDay
44%9%13%19%13%1
2520
21st to endDay
47%9%15%18%11%
2520
July1st to 10thDay
39%11%14%22%13%1
2450
11th to 20thDay
38%11%16%27%8%
2445
21st to endDay
40%10%15%23%10%1
2591
August1st to 10thDay
37%11%19%22%9%1
2492
11th to 20thDay
41%11%17%21%9%
2157
21st to endDay
38%9%15%25%13%1
2376
September1st to 10thDay
37%8%13%28%12%1
2160
11th to 20thDay
35%8%11%27%19%1
2074
21st to endDay
38%9%13%25%13%1
1980
October1st to 10thDay
51%8%9%19%12%1
1883
11th to 20thDay
43%9%17%23%7%1
1792
21st to endDay
56%8%13%14%8%1
1782
November1st to 10thDay
42%8%15%22%11%1
1671
11th to 20thDay
47%8%13%17%13%1
1710
21st to endDay
51%8%17%17%6%1
1544
December1st to 10thDay
59%8%14%13%6%1
1520
11th to 20thDay
55%7%15%16%5%1
1906
21st to endDay
66%6%9%12%7%
2772
January1st to 10thNight
53%8%14%14%10%1
2649
11th to 20thNight
58%8%12%13%7%1
2535
21st to endNight
52%6%13%17%10%2
2743
February1st to 10thNight
59%8%13%13%6%1
2340
11th to 20thNight
52%8%12%18%9%1
2131
21st to endNight
52%7%13%18%8%2
1776
March1st to 10thNight
50%8%11%20%10%1
2160
11th to 20thNight
51%7%11%18%11%2
2094
21st to endNight
48%5%10%17%16%4
1980
April1st to 10thNight
49%6%11%21%11%2
1800
11th to 20thNight
48%6%11%22%12%1
1775
21st to endNight
48%7%10%17%13%4
1697
May1st to 10thNight
52%7%8%16%14%2
1580
11th to 20thNight
46%6%11%19%14%2
1416
21st to endNight
41%8%15%20%13%2
1551
June1st to 10thNight
44%9%14%21%10%2
1440
11th to 20thNight
42%9%15%22%12%1
1440
21st to endNight
40%12%13%22%12%1
1440
July1st to 10thNight
38%9%16%22%14%1
1400
11th to 20thNight
37%10%17%26%10%1
1392
21st to endNight
36%9%15%26%12%2
1486
August1st to 10thNight
33%9%19%27%11%1
1422
11th to 20thNight
39%10%18%22%11%
1722
21st to endNight
36%9%14%27%14%1
1980
September1st to 10thNight
37%8%14%27%13%1
1800
11th to 20thNight
33%7%14%27%18%1
1885
21st to endNight
38%8%13%24%16%2
1980
October1st to 10thNight
50%7%11%20%11%1
2074
11th to 20thNight
45%9%15%22%8%1
2168
21st to endNight
54%8%13%15%9%1
2574
November1st to 10thNight
45%6%13%20%13%2
2407
11th to 20thNight
46%7%13%21%11%2
2470
21st to endNight
48%8%17%19%7%
2632
December1st to 10thNight
58%8%14%16%4
2660
11th to 20thNight
55%8%14%15%8%
3288
21st to endNight
63%8%10%15%4
4884

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
23%21%29%18%7%1
180
11th to 20thDay
27%26%30%14%11
162
21st to endDay
21%22%36%16%5%1
188
February1st to 10thDay
30%28%31%10%
240
11th to 20thDay
24%24%36%13%2
384
21st to endDay
28%18%33%18%2
346
March1st to 10thDay
24%15%35%21%4
420
11th to 20thDay
26%21%31%16%5%
420
21st to endDay
28%20%27%14%8%2
462
April1st to 10thDay
29%19%27%17%8%1
420
11th to 20thDay
27%22%27%14%8%2
412
21st to endDay
30%15%32%15%6%2
420
May1st to 10thDay
31%15%29%13%9%2
423
11th to 20thDay
17%16%36%22%7%2
447
21st to endDay
15%15%31%25%12%3
485
June1st to 10thDay
16%14%33%24%10%3
450
11th to 20thDay
19%14%30%25%10%2
450
21st to endDay
16%13%32%26%11%2
450
July1st to 10thDay
13%8%28%31%17%4
445
11th to 20thDay
12%7%31%31%15%3
444
21st to endDay
14%5%37%31%11%2
488
August1st to 10thDay
11%8%28%30%17%6%
446
11th to 20thDay
15%6%27%29%18%6%
439
21st to endDay
12%10%26%30%16%7%
495
September1st to 10thDay
12%11%24%30%16%8%
450
11th to 20thDay
15%12%25%22%16%10%
450
21st to endDay
17%10%29%24%14%6%
450
October1st to 10thDay
26%12%25%18%14%5%
450
11th to 20thDay
17%17%32%24%9%1
446
21st to endDay
30%14%25%24%6%
396
November1st to 10thDay
21%16%26%23%14%1
365
11th to 20thDay
28%16%29%21%5%1
370
21st to endDay
25%18%35%17%4
204
December1st to 10thDay
24%22%32%17%6%
180
11th to 20thDay
32%18%33%14%2
180
21st to endDay
27%19%32%18%4
198
January1st to 10thNight
21%14%37%26%3
760
11th to 20thNight
24%16%33%24%2
725
21st to endNight
17%13%38%27%4
792
February1st to 10thNight
21%16%39%23%2
720
11th to 20thNight
18%17%41%22%2
703
21st to endNight
23%15%36%21%4
592
March1st to 10thNight
22%16%35%24%3
720
11th to 20thNight
25%14%33%23%4
720
21st to endNight
22%15%34%21%7%
792
April1st to 10thNight
25%16%31%24%4
720
11th to 20thNight
22%17%31%22%8%
711
21st to endNight
25%15%29%25%6%
617
May1st to 10thNight
26%11%26%27%9%
500
11th to 20thNight
19%10%37%28%5%1
354
21st to endNight
14%10%25%37%13%1
389
June1st to 10thNight
21%328%35%13%1
360
11th to 20thNight
18%6%26%38%11%
360
21st to endNight
13%6%27%43%11%
360
July1st to 10thNight
13%421%45%15%2
350
11th to 20thNight
14%218%47%18%1
348
21st to endNight
12%221%48%16%1
394
August1st to 10thNight
11%120%47%20%1
358
11th to 20thNight
14%420%38%21%3
658
21st to endNight
14%6%19%40%21%1
792
September1st to 10thNight
14%423%39%17%2
720
11th to 20thNight
16%6%23%31%20%4
720
21st to endNight
17%6%26%33%17%2
720
October1st to 10thNight
24%10%22%28%14%2
720
11th to 20thNight
20%10%26%34%10%
720
21st to endNight
29%11%28%27%6%
792
November1st to 10thNight
17%12%32%31%7%
740
11th to 20thNight
21%13%33%25%7%1
760
21st to endNight
21%13%35%25%6%1
760
December1st to 10thNight
27%13%32%24%4
760
11th to 20thNight
27%12%32%26%4
760
21st to endNight
27%14%34%23%2
836
Page generated at 2024-01-08 22:31:25. Version ac07

Copyright 2024 Attilla Danko


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