Serena
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Serena clear sky chart from 2005-11-05 to 2017-09-22.

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
39%
15980
18%
46901
11%
15937
45%
15937
24%
31229

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
14%
2506
4%
895
31%
895
19%
1811
January16th to endNight
22%
960
12%
2624
5%
960
28%
960
17%
1969
February1st to 15thNight
23%
813
14%
2224
4%
813
31%
813
20%
1593
February16th to endNight
29%
631
18%
1893
8%
631
38%
631
18%
1327
March1st to 15thNight
27%
720
14%
2160
9%
720
32%
720
19%
1500
March16th to endNight
28%
597
14%
2004
9%
597
37%
597
18%
1415
April1st to 15thNight
30%
539
15%
1797
11%
539
39%
539
21%
1208
April16th to endNight
34%
540
18%
1761
11%
540
44%
540
22%
1173
May1st to 15thNight
33%
540
15%
1578
8%
540
40%
540
23%
1094
May16th to endNight
51%
563
19%
1498
10%
561
57%
561
32%
964
June1st to 15thNight
53%
540
17%
1440
11%
540
57%
540
35%
915
June16th to endNight
52%
540
17%
1440
11%
540
55%
540
32%
938
July1st to 15thNight
63%
510
17%
1360
12%
510
66%
510
37%
835
July16th to endNight
75%
564
23%
1417
17%
531
78%
531
42%
814
August1st to 15thNight
78%
539
21%
1596
20%
536
79%
536
40%
889
August16th to endNight
66%
573
21%
1910
22%
573
70%
573
34%
1081
September1st to 15thNight
64%
540
28%
1800
30%
540
68%
540
38%
953
September16th to endNight
59%
673
25%
1880
19%
673
63%
673
36%
1121
October1st to 15thNight
49%
660
28%
1919
20%
660
55%
660
34%
1137
October16th to endNight
31%
704
18%
2216
11%
704
41%
704
22%
1439
November1st to 15thNight
34%
700
23%
2276
16%
700
44%
700
25%
1387
November16th to endNight
29%
774
17%
2394
10%
774
37%
774
21%
1597
December1st to 15thNight
22%
900
12%
2520
5%
900
28%
900
17%
1889
December16th to endNight
17%
960
11%
2688
3%
960
24%
960
12%
2180

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%7%36%5%3445%7%37%
47989
Night
14%7%35%424446%40%
47069
Cloud CoverDay
14%7%35%5%3445%7%37%
47997
Night
14%7%35%424346%40%
47074
TransparencyDay
45%6%12%21%11%1
47675
Night
43%5%12%22%13%2
46901
SeeingDay
15%6%25%27%18%6%
5987
Night
18%7%28%30%13%1
15983

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
15%13%5%8%6%35%45%6%26%
1432
16th to endDay
14%15%6%9%7%35%346%25%
1599
February1st to 15thDay
16%13%47%435%346%29%
1636
16th to endDay
15%10%48%6%34346%32%
1580
March1st to 15thDay
16%11%47%5%25%446%31%
1790
16th to endDay
17%9%36%6%35%45%6%30%
2229
April1st to 15thDay
19%9%45%5%33346%33%
2151
16th to endDay
19%8%25%5%2435%7%35%
2198
May1st to 15thDay
19%8%37%6%345%5%7%30%
2370
16th to endDay
16%5%25%42445%8%37%
2617
June1st to 15thDay
11%425%5%3445%8%44%
2520
16th to endDay
10%5%246%35%6%7%8%39%
2520
July1st to 15thDay
8%324435%5%7%9%45%
2520
16th to endDay
6%424435%5%7%11%42%
2655
August1st to 15thDay
6%4245%35%5%7%8%44%
2352
16th to endDay
10%4245%35%6%5%9%43%
2292
September1st to 15thDay
12%314434446%49%
2160
16th to endDay
8%435%4345%5%8%46%
1881
October1st to 15thDay
14%6%24423337%45%
1708
16th to endDay
17%7%36%424436%39%
1655
November1st to 15thDay
14%8%15%42435%6%43%
1582
16th to endDay
19%8%47%5%22335%35%
1566
December1st to 15thDay
19%10%48%6%35%435%28%
1440
16th to endDay
22%13%5%8%5%35%346%22%
1536
January1st to 15thNight
16%11%46%5%34336%34%
2506
16th to endNight
14%11%7%9%5%24446%29%
2624
February1st to 15thNight
15%11%5%6%424446%35%
2222
16th to endNight
16%9%37%5%23345%36%
1893
March1st to 15thNight
18%11%3443434438%
2147
16th to endNight
16%9%36%5%35%446%33%
2004
April1st to 15thNight
17%9%36%424346%38%
1797
16th to endNight
19%6%25%433346%38%
1761
May1st to 15thNight
18%5%36%42446%7%35%
1578
16th to endNight
11%4244345%6%10%43%
1496
June1st to 15thNight
10%5%246%23445%50%
1440
16th to endNight
8%5%25%435%5%6%10%43%
1440
July1st to 15thNight
6%415%434448%52%
1440
16th to endNight
42134246%6%11%50%
1513
August1st to 15thNight
43134345%6%9%53%
1605
16th to endNight
10%42332445%8%51%
1910
September1st to 15thNight
11%313323346%57%
1800
16th to endNight
8%32443436%8%50%
1880
October1st to 15thNight
11%414323347%51%
1919
16th to endNight
19%7%25%324335%42%
2216
November1st to 15thNight
14%7%24424435%47%
2276
16th to endNight
18%8%35%423346%39%
2394
December1st to 15thNight
20%10%46%6%34335%31%
2520
16th to endNight
24%14%49%6%2434322%
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
15%13%6%8%6%45%35%5%26%
1432
16th to endDay
14%14%6%8%7%44336%25%
1599
February1st to 15thDay
16%13%47%435%346%29%
1636
16th to endDay
15%10%5%8%7%24346%32%
1580
March1st to 15thDay
17%10%47%5%25%446%31%
1800
16th to endDay
17%9%36%6%35%45%6%30%
2227
April1st to 15thDay
19%10%45%5%24336%33%
2151
16th to endDay
19%8%35%5%3345%6%35%
2198
May1st to 15thDay
19%8%27%6%345%47%30%
2370
16th to endDay
16%5%25%5%235%5%8%37%
2617
June1st to 15thDay
11%5%25%5%3445%8%44%
2520
16th to endDay
10%5%25%6%35%5%7%8%39%
2520
July1st to 15thDay
8%324435%5%6%9%45%
2520
16th to endDay
6%4245%36%5%7%10%43%
2655
August1st to 15thDay
6%4145%35%6%7%8%44%
2352
16th to endDay
10%4245%35%6%5%9%43%
2292
September1st to 15thDay
12%31443445%7%49%
2160
16th to endDay
8%425%5%3445%8%47%
1881
October1st to 15thDay
15%6%24414347%45%
1708
16th to endDay
17%8%25%424436%39%
1655
November1st to 15thDay
14%8%2442345%6%43%
1582
16th to endDay
20%8%46%5%23345%35%
1566
December1st to 15thDay
18%11%5%7%5%35%445%28%
1440
16th to endDay
22%12%7%7%5%34345%23%
1536
January1st to 15thNight
16%11%37%5%33336%34%
2506
16th to endNight
13%11%7%9%5%24446%29%
2624
February1st to 15thNight
15%11%5%6%424436%35%
2215
16th to endNight
16%10%37%5%34345%35%
1893
March1st to 15thNight
18%11%3443434438%
2160
16th to endNight
16%9%45%5%25%45%6%33%
2004
April1st to 15thNight
17%8%45%433346%38%
1797
16th to endNight
19%6%35%433346%38%
1761
May1st to 15thNight
18%5%35%5%2436%8%35%
1577
16th to endNight
11%41442446%10%44%
1496
June1st to 15thNight
11%425%5%23445%50%
1440
16th to endNight
8%4245%25%47%9%43%
1440
July1st to 15thNight
6%415%42445%7%52%
1440
16th to endNight
3313425%5%6%12%50%
1513
August1st to 15thNight
43244345%5%9%52%
1605
16th to endNight
10%42332446%7%51%
1910
September1st to 15thNight
11%313223346%57%
1800
16th to endNight
8%31442446%8%50%
1880
October1st to 15thNight
11%414423347%52%
1919
16th to endNight
20%7%24323345%42%
2216
November1st to 15thNight
14%7%24324335%47%
2276
16th to endNight
18%7%35%423346%39%
2394
December1st to 15thNight
21%10%46%5%34335%31%
2520
16th to endNight
24%13%49%6%2433422%
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
59%6%11%13%9%
1433
16th to endDay
60%5%12%14%6%
1599
February1st to 15thDay
57%5%12%16%6%1
1638
16th to endDay
54%411%21%6%1
1580
March1st to 15thDay
53%5%14%20%5%
1800
16th to endDay
53%7%13%19%5%
2229
April1st to 15thDay
52%411%21%10%
2151
16th to endDay
49%6%12%16%11%3
2198
May1st to 15thDay
52%6%11%22%6%
2370
16th to endDay
43%7%12%20%15%1
2621
June1st to 15thDay
38%6%12%25%16%1
2520
16th to endDay
39%8%13%21%15%2
2520
July1st to 15thDay
34%8%13%25%15%2
2371
16th to endDay
32%9%19%22%13%2
2488
August1st to 15thDay
32%9%14%26%16%1
2337
16th to endDay
35%8%12%23%16%3
2292
September1st to 15thDay
33%6%12%23%19%5%
2160
16th to endDay
34%6%11%28%18%1
1881
October1st to 15thDay
39%412%26%15%1
1708
16th to endDay
46%5%12%22%10%2
1655
November1st to 15thDay
40%5%11%25%15%2
1582
16th to endDay
51%413%22%7%
1566
December1st to 15thDay
58%413%16%6%
1440
16th to endDay
64%410%12%7%
1536
January1st to 15thNight
51%413%18%11%
2506
16th to endNight
54%6%15%15%7%
2624
February1st to 15thNight
50%5%12%21%9%
2224
16th to endNight
49%5%12%22%8%1
1893
March1st to 15thNight
50%413%19%9%2
2160
16th to endNight
50%7%12%18%9%1
2004
April1st to 15thNight
47%410%20%13%2
1797
16th to endNight
45%5%10%22%11%4
1761
May1st to 15thNight
46%6%13%21%11%
1578
16th to endNight
35%8%14%21%18%2
1498
June1st to 15thNight
35%5%11%24%19%3
1440
16th to endNight
35%8%12%21%17%4
1440
July1st to 15thNight
31%7%12%26%19%2
1360
16th to endNight
25%7%15%27%19%4
1417
August1st to 15thNight
25%7%17%28%18%2
1596
16th to endNight
30%6%12%26%19%4
1910
September1st to 15thNight
28%310%26%25%4
1800
16th to endNight
31%5%12%28%18%3
1880
October1st to 15thNight
32%5%9%26%23%2
1919
16th to endNight
44%410%24%15%1
2216
November1st to 15thNight
39%49%24%16%4
2276
16th to endNight
46%413%23%11%
2394
December1st to 15thNight
55%5%11%19%8%
2520
16th to endNight
66%39%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
27%10%31%22%8%
90
16th to endDay
20%8%38%22%9%
96
February1st to 15thDay
18%15%43%18%3
90
16th to endDay
19%8%35%20%14%
81
March1st to 15thDay
31%21%25%17%4
90
16th to endDay
28%10%32%18%9%2
225
April1st to 15thDay
21%12%30%24%10%1
270
16th to endDay
22%6%27%27%11%4
270
May1st to 15thDay
22%10%29%23%9%4
327
16th to endDay
17%8%29%23%16%5%
517
June1st to 15thDay
11%427%31%20%5%
495
16th to endDay
12%5%32%29%14%6%
495
July1st to 15thDay
11%320%30%23%10%
475
16th to endDay
7%20%32%27%11%
515
August1st to 15thDay
8%112%32%27%16%
416
16th to endDay
10%313%28%29%14%
332
September1st to 15thDay
11%213%31%31%9%
315
16th to endDay
8%5%15%31%31%7%
278
October1st to 15thDay
14%6%22%25%23%6%
148
16th to endDay
26%7%34%26%6%
96
November1st to 15thDay
6%10%24%35%14%8%
90
16th to endDay
41%7%28%13%8%
90
December1st to 15thDay
21%15%31%25%5%1
90
16th to endDay
29%16%45%6%2
96
January1st to 15thNight
22%12%37%22%5%
900
16th to endNight
19%12%35%28%4
960
February1st to 15thNight
22%9%36%25%5%
816
16th to endNight
20%10%34%27%6%
631
March1st to 15thNight
22%12%32%24%7%
720
16th to endNight
21%7%36%25%7%1
597
April1st to 15thNight
20%13%31%28%6%
539
16th to endNight
22%7%32%28%8%
540
May1st to 15thNight
21%6%32%29%9%
540
16th to endNight
12%426%38%17%
563
June1st to 15thNight
12%324%43%15%
540
16th to endNight
9%228%39%19%
540
July1st to 15thNight
10%16%41%28%2
510
16th to endNight
4112%46%31%4
564
August1st to 15thNight
5%7%47%33%5%
539
16th to endNight
10%113%37%33%3
573
September1st to 15thNight
12%215%36%29%4
540
16th to endNight
10%319%35%27%3
673
October1st to 15thNight
14%5%26%33%19%1
660
16th to endNight
24%9%30%25%9%
704
November1st to 15thNight
18%8%34%26%11%
700
16th to endNight
23%10%32%25%8%
774
December1st to 15thNight
27%9%32%24%6%
900
16th to endNight
29%11%33%21%3
960
Page generated at 2017-09-23 05:43:39. Version ac04

Copyright 2017 A. Danko


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