Batsto
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Batsto clear sky chart from 2005-11-05 to 2018-02-22.

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
36%
15774
20%
48899
11%
15742
47%
15742
25%
30797

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
25%
780
21%
2716
9%
776
41%
776
20%
1658
January16th to endNight
23%
832
22%
2753
8%
832
41%
832
22%
1694
February1st to 15thNight
19%
764
18%
2417
5%
761
35%
761
21%
1536
February16th to endNight
20%
659
26%
1976
9%
659
42%
659
22%
1227
March1st to 15thNight
24%
720
20%
2124
9%
720
39%
720
25%
1339
March16th to endNight
26%
768
21%
2010
8%
768
36%
768
26%
1374
April1st to 15thNight
24%
718
18%
1796
5%
718
31%
718
28%
1205
April16th to endNight
35%
720
18%
1800
7%
720
40%
720
29%
1222
May1st to 15thNight
31%
539
17%
1619
8%
539
39%
539
21%
1105
May16th to endNight
44%
374
14%
1497
12%
374
51%
374
18%
939
June1st to 15thNight
47%
360
15%
1440
15%
360
54%
360
19%
904
June16th to endNight
55%
360
16%
1440
19%
360
60%
360
25%
828
July1st to 15thNight
58%
340
12%
1360
16%
340
59%
340
20%
840
July16th to endNight
64%
384
16%
1426
16%
362
69%
362
26%
814
August1st to 15thNight
64%
615
18%
1685
12%
612
66%
612
33%
1050
August16th to endNight
62%
764
18%
1910
10%
764
63%
764
34%
1264
September1st to 15thNight
55%
720
24%
1800
14%
720
58%
720
35%
1165
September16th to endNight
55%
717
26%
1956
20%
717
59%
717
33%
1234
October1st to 15thNight
45%
720
22%
2125
18%
720
53%
720
28%
1321
October16th to endNight
35%
768
28%
2361
16%
768
52%
768
31%
1398
November1st to 15thNight
36%
760
22%
2472
14%
760
49%
760
25%
1496
November16th to endNight
32%
780
23%
2574
13%
780
46%
780
23%
1594
December1st to 15thNight
26%
780
17%
2730
7%
780
39%
780
18%
1766
December16th to endNight
21%
832
22%
2912
7%
832
40%
832
20%
1824

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
14%5%2443445%7%41%
49354
Night
14%5%2442445%7%43%
49070
Cloud CoverDay
14%5%2443445%7%42%
49363
Night
14%5%2442445%7%43%
49076
TransparencyDay
40%5%12%23%15%2
49043
Night
40%411%22%17%3
48899
SeeingDay
18%9%26%25%14%5%
6283
Night
18%9%29%30%11%1
15775

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
12%6%345%245%46%44%
1552
16th to endDay
16%6%24423346%44%
1820
February1st to 15thDay
15%8%26%424445%41%
1773
16th to endDay
12%7%36%43445%5%41%
1644
March1st to 15thDay
16%5%245%3445%6%42%
1823
16th to endDay
18%5%24433446%43%
2214
April1st to 15thDay
17%6%24323446%43%
2152
16th to endDay
14%5%24425%5%6%6%43%
2160
May1st to 15thDay
17%6%25%43445%7%39%
2343
16th to endDay
14%5%25%43446%8%40%
2618
June1st to 15thDay
13%5%35%5%35%5%5%8%38%
2520
16th to endDay
9%415%5%45%6%7%9%39%
2520
July1st to 15thDay
9%5%26%6%36%5%7%8%38%
2520
16th to endDay
7%426%6%46%6%8%11%34%
2644
August1st to 15thDay
11%5%245%446%5%9%40%
2250
16th to endDay
11%5%235%36%5%7%9%39%
2292
September1st to 15thDay
12%5%24435%45%7%45%
2160
16th to endDay
14%6%26%5%34447%40%
2002
October1st to 15thDay
18%6%2432335%5%43%
1833
16th to endDay
16%5%23323235%50%
1861
November1st to 15thDay
17%5%24423336%44%
1716
16th to endDay
15%423334446%48%
1713
December1st to 15thDay
16%6%244335%46%42%
1560
16th to endDay
20%6%24323348%39%
1664
January1st to 15thNight
16%6%2443245%6%43%
2716
16th to endNight
17%6%23324446%43%
2753
February1st to 15thNight
16%7%3442445%6%41%
2416
16th to endNight
16%5%14333446%45%
1976
March1st to 15thNight
18%424323347%45%
2111
16th to endNight
17%6%3442333444%
2010
April1st to 15thNight
16%6%24423346%44%
1796
16th to endNight
16%425%42336%7%41%
1800
May1st to 15thNight
18%7%35%42445%7%37%
1619
16th to endNight
15%7%35%5%3445%7%38%
1495
June1st to 15thNight
14%6%35%434449%40%
1440
16th to endNight
7%425%6%345%6%10%43%
1440
July1st to 15thNight
7%6%37%5%45%6%5%10%37%
1440
16th to endNight
5%425%6%36%5%6%12%41%
1522
August1st to 15thNight
8%425%436%45%8%46%
1696
16th to endNight
11%4245%25%5%6%8%43%
1910
September1st to 15thNight
12%5%15%423447%48%
1800
16th to endNight
13%6%23324348%46%
1956
October1st to 15thNight
17%424422346%45%
2125
16th to endNight
15%5%13323346%51%
2361
November1st to 15thNight
15%6%24324345%47%
2472
16th to endNight
14%6%25%42445%6%42%
2574
December1st to 15thNight
18%5%35%5%2345%6%37%
2730
16th to endNight
16%6%2443445%7%40%
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
12%6%25%4245%46%44%
1552
16th to endDay
16%7%24423346%44%
1820
February1st to 15thDay
15%8%35%424446%41%
1773
16th to endDay
13%6%36%5%345%46%40%
1644
March1st to 15thDay
16%425%426%346%42%
1833
16th to endDay
18%6%24423346%43%
2213
April1st to 15thDay
17%6%2332435%6%43%
2152
16th to endDay
15%42442446%6%43%
2160
May1st to 15thDay
16%6%25%43445%7%39%
2343
16th to endDay
14%5%2443446%8%41%
2618
June1st to 15thDay
13%5%25%5%35%5%5%9%38%
2520
16th to endDay
10%4145%36%6%6%10%40%
2520
July1st to 15thDay
8%5%35%6%35%6%6%8%39%
2520
16th to endDay
7%5%25%6%37%6%8%11%35%
2644
August1st to 15thDay
11%425%5%445%7%9%40%
2250
16th to endDay
11%4234345%6%9%41%
2292
September1st to 15thDay
12%4244345%47%46%
2160
16th to endDay
14%6%26%5%34447%39%
2002
October1st to 15thDay
18%6%24423445%43%
1833
16th to endDay
16%414322336%50%
1861
November1st to 15thDay
17%6%25%423346%44%
1716
16th to endDay
14%422434446%47%
1713
December1st to 15thDay
15%6%3442445%5%42%
1560
16th to endDay
19%7%24423446%40%
1664
January1st to 15thNight
16%6%24423447%43%
2716
16th to endNight
17%6%24323446%44%
2753
February1st to 15thNight
16%6%34424446%42%
2409
16th to endNight
15%5%24324446%45%
1976
March1st to 15thNight
17%6%24323346%46%
2124
16th to endNight
17%7%3432433444%
2010
April1st to 15thNight
16%6%24424335%45%
1796
16th to endNight
16%5%245%2345%7%42%
1800
May1st to 15thNight
18%7%35%5%25%45%6%36%
1619
16th to endNight
15%8%35%434347%39%
1495
June1st to 15thNight
15%5%25%5%25%45%8%40%
1440
16th to endNight
7%426%6%35%46%9%43%
1440
July1st to 15thNight
7%6%26%7%45%6%6%9%37%
1440
16th to endNight
5%4346%47%6%7%9%41%
1522
August1st to 15thNight
7%5%25%435%45%9%46%
1696
16th to endNight
10%425%4346%5%8%43%
1910
September1st to 15thNight
12%42442435%7%47%
1800
16th to endNight
13%6%1442445%8%44%
1956
October1st to 15thNight
16%5%2442335%7%44%
2125
16th to endNight
14%423323345%51%
2361
November1st to 15thNight
15%6%24423345%47%
2472
16th to endNight
14%6%25%42445%6%43%
2574
December1st to 15thNight
18%6%35%5%2345%6%38%
2730
16th to endNight
16%6%2442445%7%41%
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
40%414%20%14%5%
1553
16th to endDay
41%310%25%15%3
1820
February1st to 15thDay
43%411%24%13%2
1776
16th to endDay
43%49%26%12%2
1644
March1st to 15thDay
42%413%24%13%2
1833
16th to endDay
42%49%22%17%3
2214
April1st to 15thDay
40%410%24%14%5%
2152
16th to endDay
39%5%10%18%21%4
2160
May1st to 15thDay
43%5%11%22%14%2
2343
16th to endDay
39%6%15%23%12%1
2622
June1st to 15thDay
42%8%12%23%11%1
2520
16th to endDay
38%9%13%22%15%1
2520
July1st to 15thDay
41%7%11%24%13%2
2371
16th to endDay
38%9%13%24%11%2
2477
August1st to 15thDay
38%7%14%21%16%1
2237
16th to endDay
37%6%14%20%17%2
2292
September1st to 15thDay
36%5%12%20%22%2
2160
16th to endDay
43%48%19%22%2
2002
October1st to 15thDay
41%411%23%17%2
1833
16th to endDay
37%39%26%21%2
1861
November1st to 15thDay
41%212%24%16%2
1716
16th to endDay
37%39%27%18%2
1713
December1st to 15thDay
41%416%22%12%2
1560
16th to endDay
44%414%21%13%1
1664
January1st to 15thNight
40%411%20%17%4
2716
16th to endNight
41%310%26%16%1
2753
February1st to 15thNight
42%312%23%14%3
2417
16th to endNight
39%410%23%18%4
1976
March1st to 15thNight
40%412%23%16%3
2124
16th to endNight
44%310%19%17%4
2010
April1st to 15thNight
41%311%22%17%4
1796
16th to endNight
40%6%9%17%22%3
1800
May1st to 15thNight
47%49%20%15%2
1619
16th to endNight
44%6%14%17%14%2
1497
June1st to 15thNight
42%7%11%20%16%
1440
16th to endNight
35%7%14%23%16%2
1440
July1st to 15thNight
41%7%15%19%13%2
1360
16th to endNight
34%8%17%25%13%1
1426
August1st to 15thNight
34%6%14%23%19%1
1685
16th to endNight
36%6%13%20%20%2
1910
September1st to 15thNight
36%5%11%22%21%2
1800
16th to endNight
37%48%23%23%2
1956
October1st to 15thNight
39%411%23%17%3
2125
16th to endNight
34%49%28%19%3
2361
November1st to 15thNight
38%410%22%18%5%
2472
16th to endNight
41%410%23%17%3
2574
December1st to 15thNight
46%412%21%12%1
2730
16th to endNight
43%412%23%14%1
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
15%25%35%13%7%2
90
16th to endDay
26%19%33%18%2
132
February1st to 15thDay
21%24%37%15%1
199
16th to endDay
16%18%40%21%2
265
March1st to 15thDay
21%17%29%24%7%
270
16th to endDay
21%14%36%19%43
288
April1st to 15thDay
24%10%33%20%8%2
270
16th to endDay
21%6%31%22%12%4
270
May1st to 15thDay
29%14%25%15%12%2
288
16th to endDay
19%6%19%31%17%5%
331
June1st to 15thDay
17%7%24%28%15%5%
315
16th to endDay
13%5%30%31%14%5%
315
July1st to 15thDay
15%320%31%21%5%
305
16th to endDay
9%317%34%25%9%
326
August1st to 15thDay
14%117%33%23%10%
313
16th to endDay
12%15%33%23%15%
332
September1st to 15thDay
13%424%23%19%13%
315
16th to endDay
21%320%27%14%12%
314
October1st to 15thDay
23%417%29%17%6%
315
16th to endDay
15%9%31%24%17%2
321
November1st to 15thDay
19%10%28%25%15%1
280
16th to endDay
17%13%35%18%12%2
243
December1st to 15thDay
24%17%32%14%10%1
90
16th to endDay
34%12%34%17%1
96
January1st to 15thNight
19%15%34%25%5%
780
16th to endNight
22%12%37%25%1
832
February1st to 15thNight
20%14%40%22%1
764
16th to endNight
20%17%37%21%2
659
March1st to 15thNight
22%13%35%24%4
720
16th to endNight
20%11%36%23%7%1
768
April1st to 15thNight
18%14%38%23%4
718
16th to endNight
19%8%33%31%7%
720
May1st to 15thNight
21%7%33%28%7%
539
16th to endNight
18%320%40%16%
375
June1st to 15thNight
16%323%40%14%
360
16th to endNight
7%123%49%17%
360
July1st to 15thNight
11%118%48%19%
340
16th to endNight
7%216%45%26%2
384
August1st to 15thNight
10%113%48%23%2
615
16th to endNight
13%113%39%28%3
764
September1st to 15thNight
15%319%37%20%3
720
16th to endNight
17%416%33%23%3
717
October1st to 15thNight
20%422%30%18%3
720
16th to endNight
17%8%33%27%11%
768
November1st to 15thNight
17%10%30%27%12%1
760
16th to endNight
16%12%31%28%9%1
780
December1st to 15thNight
22%11%33%22%9%1
780
16th to endNight
19%13%39%23%3
832
Page generated at 2018-02-23 11:21:33. Version ac04

Copyright 2018 A. Danko


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