Bella Vista
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bella Vista clear sky chart from 2005-11-05 to 2017-09-24.

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
39%
15782
25%
47221
14%
15735
49%
15735
31%
28027

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
22%
900
26%
2327
8%
895
36%
895
27%
1498
January16th to endNight
24%
960
28%
2496
8%
960
37%
960
30%
1516
February1st to 15thNight
20%
880
20%
2288
5%
876
29%
876
27%
1490
February16th to endNight
19%
614
26%
1876
7%
614
35%
614
25%
1135
March1st to 15thNight
25%
540
22%
1980
10%
540
40%
540
20%
1250
March16th to endNight
25%
576
17%
2112
11%
576
35%
576
19%
1356
April1st to 15thNight
28%
539
23%
1851
13%
539
45%
539
26%
1079
April16th to endNight
27%
540
21%
1788
11%
540
43%
540
25%
1106
May1st to 15thNight
36%
540
21%
1620
15%
540
46%
540
28%
1027
May16th to endNight
43%
563
19%
1685
15%
561
52%
561
30%
1040
June1st to 15thNight
63%
540
20%
1620
17%
540
67%
540
43%
862
June16th to endNight
65%
540
23%
1620
17%
540
71%
540
45%
846
July1st to 15thNight
66%
510
19%
1530
18%
510
69%
510
40%
845
July16th to endNight
78%
564
28%
1594
30%
531
81%
531
44%
844
August1st to 15thNight
76%
539
26%
1610
29%
536
78%
536
41%
869
August16th to endNight
72%
573
26%
1863
29%
573
75%
573
38%
995
September1st to 15thNight
64%
540
27%
1839
29%
540
68%
540
34%
1016
September16th to endNight
58%
522
32%
1917
27%
522
68%
522
35%
979
October1st to 15thNight
49%
660
30%
1980
20%
660
57%
660
38%
1118
October16th to endNight
38%
704
30%
2112
15%
704
51%
704
36%
1185
November1st to 15thNight
36%
700
32%
2100
14%
700
53%
700
37%
1158
November16th to endNight
27%
878
27%
2385
11%
878
40%
878
30%
1479
December1st to 15thNight
25%
900
21%
2520
7%
900
36%
900
27%
1624
December16th to endNight
23%
960
25%
2508
8%
960
35%
960
24%
1710

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
13%6%2442445%7%44%
47700
Night
10%5%24323346%50%
47416
TransparencyDay
39%5%12%24%15%3
47400
Night
34%410%25%20%4
47221
SeeingDay
14%7%26%28%19%4
5814
Night
14%10%31%27%14%1
15782

By Month

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
14%7%25%312236%49%
1611
16th to endDay
13%7%23313346%48%
1728
February1st to 15thDay
12%9%35%5%23336%43%
1575
16th to endDay
13%8%45%423346%43%
1606
March1st to 15thDay
16%8%35%423445%41%
1980
16th to endDay
21%7%35%42444437%
2110
April1st to 15thDay
17%6%245%24346%42%
2097
16th to endDay
19%7%26%5%34345%36%
2169
May1st to 15thDay
18%6%35%5%25%445%37%
2331
16th to endDay
12%6%26%5%35%5%5%7%38%
2430
June1st to 15thDay
9%434435%5%6%9%44%
2340
16th to endDay
6%313435%6%6%10%47%
2340
July1st to 15thDay
9%4246%45%7%7%9%37%
2340
16th to endDay
6%2145%35%6%8%11%44%
2466
August1st to 15thDay
7%3145%45%6%7%9%43%
2340
16th to endDay
7%4245%35%5%6%8%45%
2339
September1st to 15thDay
14%5%24424347%45%
2118
16th to endDay
8%5%2442445%8%49%
1890
October1st to 15thDay
14%424323346%50%
1650
16th to endDay
12%413412235%57%
1760
November1st to 15thDay
10%6%33413336%53%
1758
16th to endDay
16%8%24212325%48%
1569
December1st to 15thDay
16%7%36%423435%43%
1440
16th to endDay
16%9%35%323346%41%
1713
January1st to 15thNight
14%5%24423235%50%
2327
16th to endNight
10%6%35%322335%53%
2496
February1st to 15thNight
12%8%35%323346%46%
2278
16th to endNight
11%5%35%424335%48%
1876
March1st to 15thNight
12%8%35%5%24445%42%
1980
16th to endNight
17%7%25%433345%41%
2112
April1st to 15thNight
11%6%14424345%50%
1851
16th to endNight
14%5%25%432446%45%
1788
May1st to 15thNight
13%4245%24445%47%
1619
16th to endNight
11%424425%46%9%45%
1683
June1st to 15thNight
431332335%9%57%
1620
16th to endNight
321322445%9%59%
1620
July1st to 15thNight
6%31432445%11%51%
1620
16th to endNight
32144245%6%8%56%
1702
August1st to 15thNight
421343447%11%52%
1620
16th to endNight
42234346%6%9%53%
1863
September1st to 15thNight
11%413324347%52%
1839
16th to endNight
7%42442335%7%55%
1917
October1st to 15thNight
10%31322335%6%55%
1980
16th to endNight
11%5%1322333457%
2112
November1st to 15thNight
9%413223435%59%
2100
16th to endNight
13%7%2431323453%
2385
December1st to 15thNight
16%6%35%322346%45%
2520
16th to endNight
14%10%45%5%1333443%
2508

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
37%29%27%19%2
1612
16th to endDay
36%211%28%16%3
1728
February1st to 15thDay
43%312%25%12%2
1576
16th to endDay
42%39%24%15%3
1606
March1st to 15thDay
44%38%20%16%5%
1980
16th to endDay
50%410%21%12%
2112
April1st to 15thDay
43%412%21%16%1
2097
16th to endDay
50%49%17%15%2
2169
May1st to 15thDay
48%5%10%20%13%
2331
16th to endDay
43%7%14%23%11%
2434
June1st to 15thDay
34%7%14%26%15%
2340
16th to endDay
29%7%18%24%17%2
2340
July1st to 15thDay
37%9%15%25%10%1
2201
16th to endDay
30%7%17%30%13%1
2311
August1st to 15thDay
33%9%14%23%17%2
2326
16th to endDay
34%7%12%26%13%5%
2339
September1st to 15thDay
38%411%22%16%7%
2118
16th to endDay
31%413%26%19%3
1890
October1st to 15thDay
34%410%24%19%5%
1650
16th to endDay
31%38%30%19%6%
1760
November1st to 15thDay
33%28%27%19%8%
1758
16th to endDay
40%37%21%24%2
1569
December1st to 15thDay
44%39%23%16%1
1440
16th to endDay
45%39%23%14%3
1713
January1st to 15thNight
38%37%27%20%3
2327
16th to endNight
33%211%27%20%3
2496
February1st to 15thNight
40%310%26%15%3
2288
16th to endNight
37%310%26%19%2
1876
March1st to 15thNight
43%5%8%18%19%4
1980
16th to endNight
45%49%22%15%1
2112
April1st to 15thNight
35%5%10%24%20%4
1851
16th to endNight
38%5%10%24%18%2
1788
May1st to 15thNight
39%5%11%22%18%2
1620
16th to endNight
35%7%18%24%14%1
1685
June1st to 15thNight
23%6%15%30%21%2
1620
16th to endNight
21%6%14%32%20%4
1620
July1st to 15thNight
26%6%13%32%18%2
1530
16th to endNight
22%6%13%36%19%1
1594
August1st to 15thNight
23%7%15%28%22%2
1610
16th to endNight
24%7%14%25%20%6%
1863
September1st to 15thNight
31%5%9%26%17%9%
1839
16th to endNight
28%410%26%26%4
1917
October1st to 15thNight
29%5%11%22%23%8%
1980
16th to endNight
30%37%26%24%7%
2112
November1st to 15thNight
28%38%26%23%8%
2100
16th to endNight
36%36%23%24%5%
2385
December1st to 15thNight
40%311%23%18%2
2520
16th to endNight
45%38%21%16%4
2508

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
26%17%34%20%1
90
16th to endDay
17%31%34%11%5%
96
February1st to 15thDay
13%30%43%10%3
90
16th to endDay
20%22%39%14%2
81
March1st to 15thDay
25%31%33%7%2
90
16th to endDay
22%18%40%13%4
96
April1st to 15thDay
20%18%35%17%6%
216
16th to endDay
28%12%32%17%9%
279
May1st to 15thDay
19%11%38%22%6%2
468
16th to endDay
16%10%37%21%11%2
517
June1st to 15thDay
9%323%39%20%4
495
16th to endDay
7%226%36%24%3
495
July1st to 15thDay
11%119%39%23%4
475
16th to endDay
6%6%34%40%11%
515
August1st to 15thDay
10%12%35%35%6%
493
16th to endDay
9%114%37%29%7%
379
September1st to 15thDay
12%115%32%30%7%
273
16th to endDay
5%127%33%24%7%
114
October1st to 15thDay
7%8%40%25%10%7%
90
16th to endDay
15%345%25%8%2
96
November1st to 15thDay
13%7%33%26%15%3
90
16th to endDay
40%17%26%12%21
90
December1st to 15thDay
22%18%35%15%43
90
16th to endDay
23%25%40%8%2
96
January1st to 15thNight
19%21%34%20%4
900
16th to endNight
14%21%37%21%4
960
February1st to 15thNight
17%17%40%21%2
880
16th to endNight
19%17%41%20%2
614
March1st to 15thNight
20%11%40%24%3
540
16th to endNight
22%13%36%21%5%
576
April1st to 15thNight
15%15%39%24%5%
539
16th to endNight
19%9%40%20%10%
540
May1st to 15thNight
16%5%37%28%11%
540
16th to endNight
14%432%28%17%1
563
June1st to 15thNight
6%222%43%23%
540
16th to endNight
4123%44%24%1
540
July1st to 15thNight
8%18%41%28%2
510
16th to endNight
47%39%41%6%
564
August1st to 15thNight
6%110%36%40%4
539
16th to endNight
414%42%33%4
573
September1st to 15thNight
14%14%36%30%2
540
16th to endNight
9%321%32%28%4
522
October1st to 15thNight
11%431%27%20%4
660
16th to endNight
16%7%35%26%12%
704
November1st to 15thNight
13%12%35%26%12%
700
16th to endNight
19%14%37%19%8%
878
December1st to 15thNight
21%14%36%23%4
900
16th to endNight
21%15%37%21%4
960
Page generated at 2017-09-25 08:02:27. Version ac04

Copyright 2017 A. Danko


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