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 2017-09-14.

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%
14632
13%
46825
8%
14600
36%
14600
16%
33385

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%
720
7%
2506
3%
716
22%
716
7%
2033
January16th to endNight
20%
768
11%
2640
6%
768
27%
768
11%
1966
February1st to 15thNight
18%
704
11%
2287
3%
701
27%
701
11%
1755
February16th to endNight
20%
631
14%
1953
6%
631
31%
631
12%
1456
March1st to 15thNight
19%
720
13%
2097
6%
720
27%
720
14%
1595
March16th to endNight
25%
768
19%
2037
9%
768
34%
768
20%
1405
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
45%
716
15%
1790
6%
716
48%
716
28%
1247
September16th to endNight
44%
657
21%
1795
14%
657
49%
657
30%
1154
October1st to 15thNight
30%
660
18%
1980
11%
660
40%
660
18%
1391
October16th to endNight
25%
704
11%
2200
6%
704
32%
704
13%
1686
November1st to 15thNight
27%
700
17%
2337
12%
700
36%
700
17%
1645
November16th to endNight
19%
720
10%
2520
6%
720
25%
720
9%
1947
December1st to 15thNight
18%
720
7%
2520
3%
720
23%
720
8%
2004
December16th to endNight
13%
768
10%
2688
3%
768
22%
768
7%
2151

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%
47898
Night
18%9%46%5%34445%32%
46994
Cloud CoverDay
21%7%36%5%34446%32%
47907
Night
20%8%36%5%34445%33%
47000
TransparencyDay
51%6%11%19%9%1
47585
Night
52%5%10%20%10%
46825
SeeingDay
22%12%28%21%10%3
5452
Night
23%11%27%25%10%
14632

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%2433421%
1432
16th to endDay
15%16%49%7%33445%23%
1581
February1st to 15thDay
13%14%6%12%6%44435%23%
1575
16th to endDay
18%13%5%8%6%335%5%425%
1518
March1st to 15thDay
18%11%47%6%45%44427%
1852
16th to endDay
15%8%36%6%33445%39%
2187
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%
2146
16th to endDay
17%5%24423346%45%
1832
October1st to 15thDay
22%7%35%5%34347%33%
1650
16th to endDay
28%8%46%5%3443424%
1672
November1st to 15thDay
15%9%36%5%35%45%7%32%
1518
16th to endDay
25%12%36%6%34345%23%
1440
December1st to 15thDay
22%15%6%9%6%34445%17%
1440
16th to endDay
23%17%5%7%6%3442420%
1536
January1st to 15thNight
19%16%6%9%7%3444418%
2506
16th to endNight
14%16%6%7%6%35%435%26%
2640
February1st to 15thNight
12%13%7%10%6%45%5%35%24%
2285
16th to endNight
17%12%5%7%7%35%44428%
1953
March1st to 15thNight
19%11%5%7%5%35%33429%
2084
16th to endNight
15%7%36%5%2333441%
2037
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%
1790
16th to endNight
18%424412235%49%
1795
October1st to 15thNight
22%6%25%5%33446%35%
1980
16th to endNight
26%8%26%6%44446%26%
2200
November1st to 15thNight
20%8%36%5%4445%6%31%
2337
16th to endNight
24%10%48%6%3444424%
2520
December1st to 15thNight
23%14%6%7%6%345%4420%
2520
16th to endNight
24%15%6%8%6%2333420%
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
22%14%5%8%6%33435%21%
1432
16th to endDay
15%15%5%8%6%3445%5%24%
1581
February1st to 15thDay
14%13%5%12%7%45%43425%
1575
16th to endDay
19%12%6%8%6%335%4426%
1518
March1st to 15thDay
26%8%35%6%3443430%
1862
16th to endDay
24%5%3442334438%
2186
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%
2146
16th to endDay
16%5%245%2325%7%44%
1832
October1st to 15thDay
20%7%36%5%3335%6%34%
1650
16th to endDay
27%8%37%5%35%335%25%
1672
November1st to 15thDay
19%8%35%435%46%5%33%
1518
16th to endDay
27%11%26%6%33445%24%
1440
December1st to 15thDay
23%14%49%6%36%35%5%17%
1440
16th to endDay
23%15%5%7%6%3443420%
1536
January1st to 15thNight
19%15%6%10%6%44445%18%
2506
16th to endNight
14%15%6%7%7%24435%27%
2640
February1st to 15thNight
15%11%5%11%7%35%445%25%
2278
16th to endNight
18%11%5%7%6%3444429%
1953
March1st to 15thNight
29%7%35%5%2422332%
2097
16th to endNight
25%5%25%41232342%
2037
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%42%
1790
16th to endNight
18%424422235%49%
1795
October1st to 15thNight
21%6%35%433436%37%
1980
16th to endNight
25%8%346%44346%27%
2200
November1st to 15thNight
25%7%35%433345%33%
2337
16th to endNight
27%9%37%6%2434427%
2520
December1st to 15thNight
24%14%5%7%5%2444421%
2520
16th to endNight
25%14%48%6%2433421%
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
66%48%13%6%
1433
16th to endDay
61%5%10%13%8%
1581
February1st to 15thDay
62%5%10%16%4
1577
16th to endDay
59%6%9%14%9%1
1518
March1st to 15thDay
59%5%10%16%7%1
1862
16th to endDay
46%48%19%14%5%
2187
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%
2146
16th to endDay
40%6%13%31%9%
1832
October1st to 15thDay
51%413%20%10%
1650
16th to endDay
61%6%11%14%6%
1672
November1st to 15thDay
49%6%14%20%8%
1518
16th to endDay
62%6%11%12%5%1
1440
December1st to 15thDay
68%7%10%11%2
1440
16th to endDay
68%410%11%5%
1536
January1st to 15thNight
68%5%7%12%5%
2506
16th to endNight
59%49%16%8%
2640
February1st to 15thNight
61%5%9%17%5%
2287
16th to endNight
57%5%8%18%9%
1953
March1st to 15thNight
58%5%8%18%8%1
2097
16th to endNight
46%48%20%16%4
2037
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%
1790
16th to endNight
39%410%35%9%
1795
October1st to 15thNight
48%6%9%23%11%
1980
16th to endNight
59%5%12%16%6%
2200
November1st to 15thNight
52%5%12%18%10%
2337
16th to endNight
62%410%16%4
2520
December1st to 15thNight
65%5%11%14%3
2520
16th to endNight
67%48%13%5%
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
35%20%25%15%5%
60
16th to endDay
38%11%32%12%5%
71
February1st to 15thDay
34%21%36%6%1
90
16th to endDay
35%20%23%16%3
177
March1st to 15thDay
25%17%32%19%4
270
16th to endDay
22%16%31%18%9%2
288
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
20%7%22%22%15%11%
310
16th to endDay
18%9%25%21%17%7%
254
October1st to 15thDay
23%12%24%27%10%1
255
16th to endDay
31%16%24%20%7%
256
November1st to 15thDay
19%12%30%25%10%2
172
16th to endDay
28%18%31%20%1
60
December1st to 15thDay
25%18%40%15%1
60
16th to endDay
40%21%32%4
64
January1st to 15thNight
28%15%28%21%5%
720
16th to endNight
22%13%32%25%5%
768
February1st to 15thNight
19%17%35%22%5%
704
16th to endNight
23%16%30%22%5%
631
March1st to 15thNight
25%14%33%22%3
720
16th to endNight
20%17%29%23%9%
768
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%24%29%20%2
716
16th to endNight
20%6%24%26%19%2
657
October1st to 15thNight
26%10%24%25%12%
660
16th to endNight
29%12%26%23%7%
704
November1st to 15thNight
25%12%28%22%11%1
700
16th to endNight
29%19%22%19%8%
720
December1st to 15thNight
29%14%30%20%3
720
16th to endNight
33%13%31%16%41
768
Page generated at 2017-09-15 10:29:57. Version ac04

Copyright 2017 A. Danko


Champlain Belvedere Clear Sky Chart | Charts Home