Champlain Belvedere
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Champlain Belvedere clear sky chart from 2005-11-05 to 2018-03-21.

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
29%
15384
13%
49250
8%
15352
36%
15352
16%
35112

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
7%
2716
2%
776
22%
776
7%
2193
January16th to endNight
19%
832
11%
2860
5%
832
26%
832
11%
2140
February1st to 15thNight
18%
764
12%
2482
3%
761
27%
761
11%
1894
February16th to endNight
20%
683
14%
2114
6%
683
30%
683
12%
1567
March1st to 15thNight
18%
780
12%
2272
6%
780
25%
780
13%
1758
March16th to endNight
25%
792
21%
2103
9%
792
35%
792
21%
1437
April1st to 15thNight
22%
718
15%
1796
5%
718
28%
718
18%
1328
April16th to endNight
28%
639
17%
1719
7%
639
35%
639
21%
1205
May1st to 15thNight
35%
360
17%
1440
16%
360
44%
360
16%
935
May16th to endNight
33%
375
13%
1497
11%
374
44%
374
18%
963
June1st to 15thNight
35%
360
10%
1440
8%
360
45%
360
15%
955
June16th to endNight
44%
360
8%
1440
11%
360
49%
360
18%
925
July1st to 15thNight
54%
340
14%
1360
19%
340
60%
340
26%
753
July16th to endNight
56%
376
14%
1418
18%
354
59%
354
27%
795
August1st to 15thNight
54%
443
15%
1514
13%
441
59%
441
25%
939
August16th to endNight
52%
705
20%
1851
11%
705
57%
705
35%
1152
September1st to 15thNight
46%
720
15%
1800
7%
720
49%
720
28%
1251
September16th to endNight
46%
717
23%
1959
16%
717
51%
717
31%
1248
October1st to 15thNight
32%
720
17%
2160
11%
720
41%
720
20%
1492
October16th to endNight
24%
768
12%
2400
6%
768
32%
768
13%
1823
November1st to 15thNight
27%
760
16%
2537
11%
760
36%
760
16%
1783
November16th to endNight
19%
780
10%
2730
6%
780
25%
780
9%
2105
December1st to 15thNight
17%
780
8%
2730
3%
780
23%
780
8%
2162
December16th to endNight
12%
832
11%
2912
3%
832
22%
832
8%
2309

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
18%8%36%5%34446%32%
49607
Night
18%9%46%5%34445%32%
49419
Cloud CoverDay
21%8%36%5%34446%32%
49616
Night
20%8%36%5%34445%33%
49425
TransparencyDay
51%6%11%19%9%1
49294
Night
52%5%10%20%10%
49250
SeeingDay
23%13%28%20%10%3
6006
Night
23%11%27%25%10%
15384

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
22%15%6%9%5%2433420%
1552
16th to endDay
15%16%5%9%7%34445%23%
1713
February1st to 15thDay
13%14%5%11%7%44445%23%
1710
16th to endDay
19%13%5%8%6%335%5%425%
1643
March1st to 15thDay
19%13%47%6%45%44425%
2007
16th to endDay
14%8%35%5%33445%40%
2249
April1st to 15thDay
24%10%35%323335%33%
2152
16th to endDay
21%8%35%42344336%
2250
May1st to 15thDay
22%7%36%5%34346%32%
2511
16th to endDay
19%6%35%6%35%45%7%33%
2618
June1st to 15thDay
22%6%35%5%35%5%5%7%29%
2520
16th to endDay
18%5%345%35%5%6%7%32%
2520
July1st to 15thDay
14%425%5%36%6%6%8%37%
2520
16th to endDay
13%5%25%5%36%6%6%8%36%
2654
August1st to 15thDay
12%5%25%6%46%5%5%8%36%
2435
16th to endDay
12%5%245%345%6%9%40%
2339
September1st to 15thDay
17%5%25%5%33447%40%
2160
16th to endDay
16%5%2442335%6%46%
1998
October1st to 15thDay
22%7%35%5%34347%33%
1800
16th to endDay
27%8%46%5%3443425%
1824
November1st to 15thDay
16%9%36%5%35%45%7%31%
1648
16th to endDay
25%11%46%6%35%335%23%
1560
December1st to 15thDay
22%15%6%9%7%34445%17%
1560
16th to endDay
22%17%5%7%6%3442421%
1664
January1st to 15thNight
19%16%6%9%7%34445%18%
2716
16th to endNight
14%16%5%7%6%35%435%26%
2860
February1st to 15thNight
12%13%6%10%6%45%5%35%25%
2480
16th to endNight
17%11%47%7%35%445%28%
2114
March1st to 15thNight
19%13%5%8%6%35%33427%
2259
16th to endNight
15%7%36%5%2333443%
2103
April1st to 15thNight
23%8%45%43344434%
1796
16th to endNight
18%8%35%5%24346%36%
1719
May1st to 15thNight
22%8%34423445%36%
1440
16th to endNight
16%6%26%5%3445%6%37%
1495
June1st to 15thNight
19%5%35%6%245%5%7%33%
1440
16th to endNight
17%5%245%35%5%5%7%37%
1440
July1st to 15thNight
11%324425%448%46%
1440
16th to endNight
9%4144346%6%7%46%
1514
August1st to 15thNight
10%5%25%5%2347%10%41%
1524
16th to endNight
9%315%42445%6%50%
1851
September1st to 15thNight
14%7%25%4345%5%5%42%
1800
16th to endNight
17%425%413235%49%
1959
October1st to 15thNight
21%6%25%5%33446%36%
2160
16th to endNight
25%8%26%6%34446%27%
2400
November1st to 15thNight
21%8%35%434446%31%
2537
16th to endNight
24%10%48%6%34445%24%
2730
December1st to 15thNight
22%14%6%8%6%3444420%
2730
16th to endNight
23%15%6%8%6%2433421%
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
22%15%6%8%6%34435%20%
1552
16th to endDay
15%15%5%8%7%3445%5%23%
1713
February1st to 15thDay
14%13%5%11%7%35%435%24%
1710
16th to endDay
19%12%6%7%6%335%4425%
1643
March1st to 15thDay
26%10%35%5%3442429%
2017
16th to endDay
24%5%3442334439%
2248
April1st to 15thDay
27%8%35%313345%32%
2152
16th to endDay
24%7%35%42344436%
2250
May1st to 15thDay
29%6%25%42434431%
2511
16th to endDay
27%5%245%34436%32%
2618
June1st to 15thDay
25%5%36%425%447%30%
2520
16th to endDay
22%5%25%426%6%6%7%31%
2520
July1st to 15thDay
13%425%5%36%5%6%9%37%
2520
16th to endDay
12%5%25%5%35%5%6%9%37%
2654
August1st to 15thDay
23%4145%35%5%46%36%
2435
16th to endDay
22%313323447%41%
2339
September1st to 15thDay
17%5%145%34447%41%
2160
16th to endDay
15%5%245%2335%7%45%
1998
October1st to 15thDay
20%7%35%5%3335%6%34%
1800
16th to endDay
26%7%36%5%35%446%26%
1824
November1st to 15thDay
19%8%35%435%5%6%5%32%
1648
16th to endDay
26%11%26%6%34445%24%
1560
December1st to 15thDay
22%14%49%6%35%35%5%18%
1560
16th to endDay
23%15%5%7%6%3443421%
1664
January1st to 15thNight
19%15%6%10%6%34445%19%
2716
16th to endNight
14%15%6%7%7%24435%26%
2860
February1st to 15thNight
14%12%5%10%7%35%445%25%
2473
16th to endNight
18%11%5%7%6%345%4429%
2114
March1st to 15thNight
28%9%36%5%2322330%
2272
16th to endNight
24%5%25%41232343%
2103
April1st to 15thNight
26%7%3442333434%
1796
16th to endNight
20%8%25%424345%37%
1719
May1st to 15thNight
26%7%33423346%34%
1440
16th to endNight
20%6%25%5%235%45%37%
1495
June1st to 15thNight
19%6%25%6%3445%7%34%
1440
16th to endNight
19%5%24426%46%6%37%
1440
July1st to 15thNight
10%424435%46%7%47%
1440
16th to endNight
9%4235%25%5%5%8%46%
1514
August1st to 15thNight
15%5%2432245%8%44%
1524
16th to endNight
17%31333335%5%50%
1851
September1st to 15thNight
15%5%25%5%34446%43%
1800
16th to endNight
17%414423235%50%
1959
October1st to 15thNight
20%6%25%433436%38%
2160
16th to endNight
25%8%25%6%44446%28%
2400
November1st to 15thNight
25%7%35%433345%33%
2537
16th to endNight
27%9%37%5%2434427%
2730
December1st to 15thNight
23%14%47%5%3444421%
2730
16th to endNight
24%14%48%6%2433422%
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
66%5%7%12%6%
1553
16th to endDay
62%5%10%13%7%
1713
February1st to 15thDay
63%49%16%4
1712
16th to endDay
59%5%9%14%9%1
1643
March1st to 15thDay
61%5%9%15%7%1
2017
16th to endDay
45%48%19%15%5%
2249
April1st to 15thDay
52%47%19%13%2
2152
16th to endDay
50%46%19%15%3
2250
May1st to 15thDay
52%5%6%19%13%2
2511
16th to endDay
49%6%10%19%11%1
2622
June1st to 15thDay
52%7%10%20%8%
2520
16th to endDay
47%7%11%20%10%
2520
July1st to 15thDay
38%8%14%26%12%
2371
16th to endDay
43%7%16%23%9%
2487
August1st to 15thDay
42%8%16%22%9%
2421
16th to endDay
37%6%16%29%9%
2339
September1st to 15thDay
41%6%12%26%11%
2160
16th to endDay
38%6%13%32%9%
1998
October1st to 15thDay
50%413%20%9%
1800
16th to endDay
60%6%12%14%6%
1824
November1st to 15thDay
50%6%13%19%8%
1648
16th to endDay
62%6%10%12%6%1
1560
December1st to 15thDay
67%6%9%11%3
1560
16th to endDay
67%39%12%6%
1664
January1st to 15thNight
68%5%8%12%5%
2716
16th to endNight
60%49%16%8%
2860
February1st to 15thNight
60%5%9%17%6%
2482
16th to endNight
56%5%8%18%10%
2114
March1st to 15thNight
60%47%17%8%1
2272
16th to endNight
45%48%20%17%3
2103
April1st to 15thNight
51%48%18%15%1
1796
16th to endNight
48%47%18%17%3
1719
May1st to 15thNight
49%47%20%15%3
1440
16th to endNight
45%6%11%20%14%2
1497
June1st to 15thNight
47%7%11%22%9%1
1440
16th to endNight
43%9%10%21%14%
1440
July1st to 15thNight
33%6%12%31%14%1
1360
16th to endNight
34%5%15%27%15%
1418
August1st to 15thNight
37%8%17%24%11%
1514
16th to endNight
32%6%15%33%11%
1851
September1st to 15thNight
42%6%10%27%11%
1800
16th to endNight
38%410%35%10%
1959
October1st to 15thNight
47%6%9%24%11%
2160
16th to endNight
58%5%12%17%5%
2400
November1st to 15thNight
52%412%19%9%
2537
16th to endNight
62%410%16%4
2730
December1st to 15thNight
65%5%10%13%4
2730
16th to endNight
66%47%13%6%
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
31%18%30%15%4
90
16th to endDay
33%14%35%12%3
107
February1st to 15thDay
34%20%36%8%
135
16th to endDay
34%23%24%15%3
224
March1st to 15thDay
28%18%31%16%4
330
16th to endDay
21%18%31%18%8%1
311
April1st to 15thDay
29%24%23%14%7%
270
16th to endDay
24%20%24%18%10%1
270
May1st to 15thDay
30%10%29%16%9%3
288
16th to endDay
20%13%35%18%10%2
331
June1st to 15thDay
26%10%32%20%8%1
315
16th to endDay
20%10%30%24%12%2
315
July1st to 15thDay
15%6%31%27%13%5%
305
16th to endDay
13%331%29%16%5%
326
August1st to 15thDay
13%6%23%33%16%6%
313
16th to endDay
13%5%27%25%17%9%
332
September1st to 15thDay
19%7%22%21%16%12%
315
16th to endDay
16%10%21%21%20%9%
314
October1st to 15thDay
23%12%26%25%10%2
315
16th to endDay
30%16%25%20%6%
312
November1st to 15thDay
22%11%30%25%8%1
212
16th to endDay
26%24%33%14%1
90
December1st to 15thDay
26%16%42%11%3
90
16th to endDay
39%25%29%6%
96
January1st to 15thNight
28%15%29%21%5%
780
16th to endNight
23%14%32%24%5%
832
February1st to 15thNight
20%17%35%22%5%
764
16th to endNight
23%16%31%22%5%
683
March1st to 15thNight
26%13%33%21%4
780
16th to endNight
19%17%30%22%9%
792
April1st to 15thNight
27%15%28%23%4
718
16th to endNight
23%16%27%24%7%
639
May1st to 15thNight
24%8%24%30%9%1
360
16th to endNight
20%8%32%26%12%
375
June1st to 15thNight
21%7%27%31%10%
360
16th to endNight
18%5%23%38%13%1
360
July1st to 15thNight
10%224%42%19%
340
16th to endNight
10%223%42%19%1
376
August1st to 15thNight
15%217%39%22%2
443
16th to endNight
11%421%36%23%2
705
September1st to 15thNight
18%5%23%28%20%2
720
16th to endNight
19%6%23%25%22%2
717
October1st to 15thNight
25%9%24%26%13%1
720
16th to endNight
29%12%27%22%7%
768
November1st to 15thNight
26%11%26%23%10%1
760
16th to endNight
29%19%23%19%8%
780
December1st to 15thNight
30%14%30%20%3
780
16th to endNight
32%13%32%16%41
832
Page generated at 2018-03-22 11:34:19. Version ac04

Copyright 2018 A. Danko


Champlain Belvedere Clear Sky Chart |Charts Home