Harmony
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Harmony clear sky chart from 2005-11-05 to 2017-09-18.

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
61%
16037
20%
46940
16%
15996
65%
15996
29%
29966

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
47%
718
19%
2327
14%
716
55%
716
25%
1454
January16th to endNight
47%
768
23%
2475
18%
768
56%
768
28%
1496
February1st to 15thNight
47%
701
24%
2103
17%
698
56%
698
33%
1256
February16th to endNight
48%
631
26%
1798
15%
631
58%
631
36%
1051
March1st to 15thNight
50%
720
29%
1980
17%
720
61%
720
40%
1132
March16th to endNight
60%
768
26%
2112
20%
768
64%
768
42%
1204
April1st to 15thNight
61%
718
23%
1976
18%
718
65%
718
42%
1128
April16th to endNight
62%
720
25%
1818
16%
720
66%
720
42%
1075
May1st to 15thNight
69%
626
26%
1706
18%
626
72%
626
41%
994
May16th to endNight
73%
561
20%
1683
16%
561
74%
561
32%
1052
June1st to 15thNight
67%
540
12%
1620
10%
540
68%
540
21%
1146
June16th to endNight
70%
540
9%
1620
8%
540
70%
540
21%
1173
July1st to 15thNight
71%
510
6%
1530
5%
510
71%
510
18%
1133
July16th to endNight
75%
564
8%
1595
8%
531
76%
531
22%
1152
August1st to 15thNight
79%
539
7%
1609
7%
536
80%
536
24%
1120
August16th to endNight
65%
752
7%
2028
7%
752
65%
752
19%
1516
September1st to 15thNight
64%
720
7%
1980
7%
720
64%
720
18%
1498
September16th to endNight
61%
669
11%
1848
11%
669
61%
669
17%
1397
October1st to 15thNight
70%
660
23%
1899
24%
660
72%
660
30%
1199
October16th to endNight
62%
704
25%
2112
24%
704
66%
704
30%
1308
November1st to 15thNight
63%
700
29%
2101
25%
700
69%
700
36%
1228
November16th to endNight
56%
720
28%
2184
25%
720
64%
720
32%
1320
December1st to 15thNight
56%
720
25%
2340
23%
720
63%
720
28%
1429
December16th to endNight
56%
768
22%
2496
21%
768
61%
768
28%
1505

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
8%5%36%7%46%6%6%8%34%
47833
Night
7%425%5%35%5%6%9%43%
47148
TransparencyDay
44%9%13%14%12%4
47534
Night
35%9%16%19%13%5%
46951
SeeingDay
10%211%20%25%29%
5871
Night
9%216%31%30%9%
16045

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
11%6%25%5%36%5%6%8%38%
1611
16th to endDay
11%5%2442445%6%47%
1746
February1st to 15thDay
11%5%344245%6%7%44%
1750
16th to endDay
8%426%6%35%5%5%5%45%
1673
March1st to 15thDay
6%325%6%45%46%7%48%
1980
16th to endDay
7%325%5%45%5%5%8%44%
2111
April1st to 15thDay
6%425%6%45%6%6%7%43%
1972
16th to endDay
6%425%7%36%6%6%8%42%
2142
May1st to 15thDay
5%4145%36%6%6%9%46%
2253
16th to endDay
7%437%8%5%7%7%7%8%31%
2431
June1st to 15thDay
12%5%37%10%5%7%6%7%10%23%
2340
16th to endDay
10%6%37%8%6%9%8%7%8%23%
2340
July1st to 15thDay
9%6%410%9%5%8%7%7%8%22%
2340
16th to endDay
9%6%5%9%9%5%8%8%6%8%20%
2465
August1st to 15thDay
5%6%39%10%5%8%8%9%9%23%
2337
16th to endDay
12%7%38%8%5%8%6%8%8%22%
2157
September1st to 15thDay
9%6%37%10%6%7%9%7%8%23%
1980
16th to endDay
11%7%49%9%6%7%7%6%8%20%
1837
October1st to 15thDay
8%6%26%8%47%7%6%8%32%
1730
16th to endDay
10%425%5%35%46%6%43%
1760
November1st to 15thDay
5%425%6%25%6%5%9%46%
1757
16th to endDay
7%6%26%6%45%46%7%40%
1773
December1st to 15thDay
10%6%46%5%46%5%6%7%37%
1620
16th to endDay
8%5%25%5%36%5%7%8%42%
1728
January1st to 15thNight
10%6%26%5%245%5%8%42%
2327
16th to endNight
10%5%25%4245%5%7%44%
2475
February1st to 15thNight
11%5%24423345%51%
2103
16th to endNight
8%3244245%48%51%
1798
March1st to 15thNight
5%314434448%55%
1980
16th to endNight
5%32343446%8%55%
2112
April1st to 15thNight
5%2134244410%53%
1976
16th to endNight
5%3134235%6%9%53%
1818
May1st to 15thNight
43235%2445%9%54%
1706
16th to endNight
5%325%436%6%7%8%45%
1682
June1st to 15thNight
9%6%36%5%36%7%6%12%30%
1620
16th to endNight
7%7%36%7%47%6%7%11%31%
1620
July1st to 15thNight
6%6%27%7%47%8%8%9%31%
1620
16th to endNight
6%436%7%47%7%9%11%32%
1703
August1st to 15thNight
4425%7%47%7%9%11%36%
1620
16th to endNight
9%5%37%7%46%6%7%10%31%
2028
September1st to 15thNight
7%7%37%7%47%7%8%10%28%
1980
16th to endNight
9%8%37%6%46%7%7%10%27%
1848
October1st to 15thNight
7%5%15%5%345%5%8%45%
1899
16th to endNight
10%5%35%434448%46%
2112
November1st to 15thNight
6%3245%3445%7%52%
2101
16th to endNight
9%4235%345%6%8%46%
2184
December1st to 15thNight
9%4245%35%5%5%8%44%
2340
16th to endNight
6%4345%345%7%8%45%
2496

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
41%7%8%18%17%6%
1612
16th to endDay
36%47%18%22%9%
1746
February1st to 15thDay
37%7%7%13%21%12%
1752
16th to endDay
38%5%9%16%20%9%
1673
March1st to 15thDay
33%6%11%22%18%7%
1980
16th to endDay
35%6%12%18%18%7%
2112
April1st to 15thDay
36%6%13%18%18%6%
1972
16th to endDay
37%6%11%16%21%7%
2142
May1st to 15thDay
31%8%13%19%19%7%
2253
16th to endDay
45%9%12%15%13%2
2435
June1st to 15thDay
52%12%16%15%3
2340
16th to endDay
53%13%17%11%3
2340
July1st to 15thDay
55%15%18%9%1
2201
16th to endDay
56%13%18%10%1
2310
August1st to 15thDay
49%16%23%8%
2324
16th to endDay
55%16%19%7%1
2157
September1st to 15thDay
53%14%18%10%3
1980
16th to endDay
56%13%15%9%41
1837
October1st to 15thDay
45%9%10%14%14%5%
1730
16th to endDay
39%5%10%13%20%10%
1760
November1st to 15thDay
32%7%8%21%21%7%
1757
16th to endDay
41%6%8%15%16%11%
1773
December1st to 15thDay
44%6%11%15%15%5%
1620
16th to endDay
36%7%15%18%14%7%
1728
January1st to 15thNight
38%6%11%20%15%6%
2327
16th to endNight
36%6%9%21%17%8%
2475
February1st to 15thNight
34%48%16%21%13%
2112
16th to endNight
29%6%14%19%21%8%
1798
March1st to 15thNight
27%5%11%28%20%5%
1980
16th to endNight
25%6%14%23%20%8%
2112
April1st to 15thNight
25%6%17%23%19%7%
1976
16th to endNight
25%7%15%22%22%6%
1818
May1st to 15thNight
26%7%13%26%17%7%
1707
16th to endNight
31%10%17%21%16%1
1684
June1st to 15thNight
43%12%20%19%4
1620
16th to endNight
43%13%21%17%4
1620
July1st to 15thNight
44%15%25%12%1
1530
16th to endNight
38%17%28%13%1
1595
August1st to 15thNight
34%17%35%11%
1609
16th to endNight
44%15%25%13%
2028
September1st to 15thNight
44%17%20%14%2
1980
16th to endNight
47%14%17%14%31
1848
October1st to 15thNight
34%8%13%19%17%5%
1899
16th to endNight
37%5%9%16%23%8%
2112
November1st to 15thNight
30%6%12%21%21%7%
2101
16th to endNight
33%6%10%20%18%11%
2184
December1st to 15thNight
36%7%12%23%13%6%
2340
16th to endNight
34%8%14%21%14%7%
2496

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
18%7%31%25%11%5%
90
16th to endDay
15%13%30%21%15%3
96
February1st to 15thDay
311%30%30%16%8%
90
16th to endDay
10%5%29%36%15%1
174
March1st to 15thDay
6%426%34%24%3
270
16th to endDay
9%5%18%26%32%8%
288
April1st to 15thDay
4422%27%30%11%
270
16th to endDay
7%13%28%27%21%
270
May1st to 15thDay
6%9%23%37%21%
288
16th to endDay
5%28%18%29%35%
331
June1st to 15thDay
16%25%13%21%40%
315
16th to endDay
9%310%21%53%
315
July1st to 15thDay
8%15%20%63%
305
16th to endDay
12%29%18%56%
326
August1st to 15thDay
8%211%18%57%
313
16th to endDay
15%39%16%54%
332
September1st to 15thDay
13%412%22%47%
315
16th to endDay
12%1411%27%41%
262
October1st to 15thDay
12%18%24%35%17%
255
16th to endDay
9%216%27%34%9%
272
November1st to 15thDay
5%113%32%36%10%
265
16th to endDay
9%320%34%26%4
243
December1st to 15thDay
20%321%37%16%1
90
16th to endDay
5%412%36%34%7%
96
January1st to 15thNight
13%5%26%32%19%2
720
16th to endNight
11%6%27%39%14%
768
February1st to 15thNight
13%5%28%38%13%
704
16th to endNight
9%5%32%41%11%
631
March1st to 15thNight
7%430%40%15%1
720
16th to endNight
6%224%43%21%1
768
April1st to 15thNight
5%223%44%21%1
718
16th to endNight
7%320%45%21%1
720
May1st to 15thNight
6%115%43%30%3
627
16th to endNight
7%7%31%44%8%
563
June1st to 15thNight
12%1422%45%14%
540
16th to endNight
7%314%47%26%
540
July1st to 15thNight
7%39%48%30%
510
16th to endNight
5%19%48%34%
564
August1st to 15thNight
5%110%48%33%
539
16th to endNight
10%5%14%42%26%
752
September1st to 15thNight
11%416%42%23%
720
16th to endNight
14%6%18%42%16%
669
October1st to 15thNight
9%8%31%41%8%
660
16th to endNight
13%112%33%32%5%
704
November1st to 15thNight
7%218%36%30%4
700
16th to endNight
9%323%38%22%1
720
December1st to 15thNight
9%421%39%24%1
720
16th to endNight
7%423%38%24%1
768
Page generated at 2017-09-19 07:32:25. Version ac04

Copyright 2017 A. Danko


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