Point Petre
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Point Petre clear sky chart from 2005-11-06 to 2024-01-31.

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
37%
22827
13%
75040
10%
22790
42%
22790
17%
53541

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 10thNight
16%
760
9%
2649
5%
757
21%
757
7%
2193
January11th to 20thNight
17%
760
6%
2660
3%
760
20%
760
6%
2223
January21st to endNight
21%
835
9%
2711
6%
835
26%
835
10%
2160
February1st to 10thNight
16%
720
6%
2340
2%
720
21%
720
8%
1939
February11th to 20thNight
20%
702
12%
2275
5%
700
30%
700
13%
1715
February21st to endNight
23%
592
11%
1805
5%
592
32%
592
14%
1362
March1st to 10thNight
27%
720
15%
2075
8%
720
33%
720
17%
1546
March11th to 20thNight
32%
720
17%
1979
9%
720
39%
720
20%
1406
March21st to endNight
35%
792
20%
2118
9%
792
42%
792
25%
1464
April1st to 10thNight
36%
720
17%
1800
5%
720
42%
720
23%
1307
April11th to 20thNight
42%
711
16%
1775
8%
711
45%
711
27%
1248
April21st to endNight
43%
626
17%
1706
9%
626
46%
626
24%
1185
May1st to 10thNight
47%
419
16%
1499
15%
419
51%
419
20%
958
May11th to 20thNight
57%
354
21%
1416
22%
354
63%
354
23%
830
May21st to endNight
64%
388
16%
1551
20%
388
68%
388
26%
859
June1st to 10thNight
58%
360
14%
1440
18%
360
63%
360
20%
897
June11th to 20thNight
59%
360
18%
1440
25%
360
66%
360
26%
810
June21st to endNight
54%
360
13%
1440
20%
360
57%
360
21%
864
July1st to 10thNight
68%
350
17%
1400
26%
350
71%
350
30%
718
July11th to 20thNight
63%
348
18%
1392
27%
348
65%
348
28%
768
July21st to endNight
66%
394
19%
1486
24%
372
69%
372
28%
793
August1st to 10thNight
64%
537
18%
1600
16%
534
66%
534
34%
948
August11th to 20thNight
61%
534
19%
1598
14%
534
64%
534
31%
984
August21st to endNight
62%
770
21%
1958
11%
770
65%
770
37%
1230
September1st to 10thNight
58%
720
18%
1800
10%
720
60%
720
34%
1171
September11th to 20thNight
60%
720
26%
1800
16%
720
64%
720
38%
1139
September21st to endNight
51%
720
21%
2062
17%
720
54%
720
28%
1351
October1st to 10thNight
40%
720
15%
2160
13%
720
43%
720
19%
1520
October11th to 20thNight
33%
720
12%
2160
9%
720
37%
720
17%
1586
October21st to endNight
27%
792
13%
2425
9%
792
34%
792
14%
1830
November1st to 10thNight
36%
740
17%
2416
14%
740
41%
740
17%
1688
November11th to 20thNight
26%
760
15%
2660
10%
760
35%
760
14%
1924
November21st to endNight
23%
760
10%
2660
6%
760
28%
760
10%
2081
December1st to 10thNight
15%
760
6%
2660
3%
760
19%
760
6%
2264
December11th to 20thNight
16%
759
6%
3273
2%
759
21%
759
6%
2634
December21st to endNight
12%
824
3%
4851
0%
817
17%
817
4%
3946

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
16%9%36%5%345%5%7%36%
74857
Night
18%10%47%6%345%5%7%31%
75261
TransparencyDay
48%413%23%11%1
74563
Night
55%411%19%10%1
75089
SeeingDay
20%417%31%22%6%
13450
Night
23%6%23%28%16%3
22842

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 10thDay
16%19%7%11%7%3445%5%18%
1517
11th to 20thDay
19%19%5%10%6%36%45%6%16%
1520
21st to endDay
14%15%7%12%8%47%5%5%6%17%
1867
February1st to 10thDay
15%15%7%15%7%35%5%5%5%17%
1620
11th to 20thDay
15%12%6%12%6%4445%6%26%
1573
21st to endDay
21%12%49%6%445%5%6%24%
1449
March1st to 10thDay
15%9%5%8%7%45%5%5%7%30%
1880
11th to 20thDay
15%10%47%7%45%45%6%34%
1980
21st to endDay
20%8%36%5%2346%5%38%
2236
April1st to 10thDay
18%8%36%6%3445%8%36%
2160
11th to 20thDay
18%7%25%5%345%45%43%
2134
21st to endDay
19%7%36%5%35%45%7%35%
2271
May1st to 10thDay
14%8%36%5%45%5%5%7%38%
2461
11th to 20thDay
13%6%35%435%5%5%9%43%
2478
21st to endDay
11%435%5%346%6%8%46%
2725
June1st to 10thDay
16%5%36%5%35%5%6%7%41%
2520
11th to 20thDay
13%5%25%5%345%5%10%44%
2520
21st to endDay
13%6%35%43445%8%46%
2520
July1st to 10thDay
8%3245%345%6%9%51%
2520
11th to 20thDay
10%42443446%9%48%
2520
21st to endDay
10%425%5%35%5%6%9%47%
2740
August1st to 10thDay
9%425%5%345%6%9%49%
2327
11th to 20thDay
10%5%25%5%346%7%9%46%
2303
21st to endDay
11%6%2443446%8%47%
2378
September1st to 10thDay
12%6%25%42445%8%47%
2160
11th to 20thDay
11%425%43445%8%50%
2160
21st to endDay
15%5%35%5%35%5%6%7%40%
1894
October1st to 10thDay
19%7%46%6%345%5%7%35%
1800
11th to 20thDay
21%7%36%5%35%5%6%8%32%
1800
21st to endDay
27%10%25%6%35%5%45%26%
1929
November1st to 10thDay
15%10%46%6%35%5%5%7%34%
1657
11th to 20thDay
16%14%5%8%7%45%5%5%5%27%
1520
21st to endDay
22%15%5%7%6%345%5%6%21%
1520
December1st to 10thDay
23%20%5%8%6%35%45%6%15%
1520
11th to 20thDay
19%18%5%10%7%345%5%5%19%
1906
21st to endDay
30%15%6%7%6%34445%16%
2772
January1st to 10thNight
20%18%6%10%7%34445%18%
2649
11th to 20thNight
21%17%6%11%8%345%46%15%
2660
21st to endNight
15%17%6%11%7%45%45%7%21%
2711
February1st to 10thNight
18%15%8%13%8%445%4418%
2340
11th to 20thNight
18%13%7%8%6%4435%7%24%
2273
21st to endNight
19%11%5%8%6%45%6%6%6%25%
1805
March1st to 10thNight
15%12%49%6%445%5%6%29%
2065
11th to 20thNight
19%10%47%5%24445%36%
1979
21st to endNight
18%7%36%6%24445%39%
2118
April1st to 10thNight
22%8%36%5%35%45%7%34%
1800
11th to 20thNight
18%8%46%5%335%5%6%38%
1775
21st to endNight
20%8%36%5%345%46%37%
1706
May1st to 10thNight
21%8%36%4245%5%8%36%
1499
11th to 20thNight
13%6%25%5%45%6%6%7%42%
1415
21st to endNight
11%5%246%35%5%6%9%44%
1550
June1st to 10thNight
16%5%36%6%35%6%7%9%35%
1440
11th to 20thNight
10%5%36%5%35%5%5%9%44%
1440
21st to endNight
11%8%36%6%35%5%5%8%41%
1440
July1st to 10thNight
7%5%35%44445%7%52%
1440
11th to 20thNight
10%5%35%5%346%6%8%46%
1440
21st to endNight
10%5%245%3447%7%49%
1574
August1st to 10thNight
9%5%26%5%3446%9%46%
1611
11th to 20thNight
9%6%26%6%35%5%6%9%44%
1598
21st to endNight
9%5%25%5%4447%9%47%
1958
September1st to 10thNight
12%6%35%5%3445%9%46%
1800
11th to 20thNight
12%5%245%335%47%50%
1800
21st to endNight
16%5%25%5%445%6%7%41%
2062
October1st to 10thNight
18%7%37%6%345%5%6%34%
2160
11th to 20thNight
21%9%47%6%45%45%6%29%
2160
21st to endNight
25%9%47%6%335%5%6%26%
2425
November1st to 10thNight
19%10%45%5%35%45%6%34%
2416
11th to 20thNight
18%12%5%6%5%445%5%7%28%
2660
21st to endNight
24%14%48%6%345%5%7%20%
2660
December1st to 10thNight
23%21%5%8%7%34445%15%
2660
11th to 20thNight
23%16%5%9%6%35%446%19%
3288
21st to endNight
32%15%5%6%5%3445%5%15%
4884

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 10thDay
71%312%11%3
1518
11th to 20thDay
72%311%9%4
1520
21st to endDay
70%410%11%41
1867
February1st to 10thDay
70%311%13%31
1620
11th to 20thDay
61%39%17%9%1
1582
21st to endDay
63%311%16%8%
1449
March1st to 10thDay
55%414%17%9%2
1883
11th to 20thDay
51%5%9%21%12%2
1980
21st to endDay
47%38%24%15%4
2236
April1st to 10thDay
47%49%23%15%2
2160
11th to 20thDay
44%49%25%16%2
2134
21st to endDay
48%410%20%15%3
2271
May1st to 10thDay
44%410%23%16%2
2461
11th to 20thDay
39%5%11%28%16%2
2482
21st to endDay
35%5%17%26%14%3
2725
June1st to 10thDay
42%5%13%23%16%2
2520
11th to 20thDay
35%413%30%15%2
2520
21st to endDay
37%5%16%26%16%1
2520
July1st to 10thDay
29%5%13%31%20%2
2450
11th to 20thDay
32%416%35%12%1
2445
21st to endDay
34%6%18%26%15%1
2587
August1st to 10thDay
32%5%18%32%12%1
2314
11th to 20thDay
34%421%27%13%1
2303
21st to endDay
34%5%13%35%12%1
2378
September1st to 10thDay
37%5%14%31%12%1
2160
11th to 20thDay
34%313%33%15%1
2160
21st to endDay
43%414%29%10%
1894
October1st to 10thDay
49%412%22%12%1
1800
11th to 20thDay
51%416%22%7%
1800
21st to endDay
60%410%18%7%1
1929
November1st to 10thDay
50%5%13%20%11%
1657
11th to 20thDay
58%5%13%14%8%1
1520
21st to endDay
66%313%13%6%
1520
December1st to 10thDay
74%312%10%2
1520
11th to 20thDay
72%412%9%3
1906
21st to endDay
74%310%12%2
2772
January1st to 10thNight
73%38%13%4
2649
11th to 20thNight
75%39%10%31
2660
21st to endNight
67%310%15%4
2711
February1st to 10thNight
72%39%12%4
2340
11th to 20thNight
62%39%18%8%1
2275
21st to endNight
60%314%16%6%1
1805
March1st to 10thNight
57%310%18%9%1
2075
11th to 20thNight
51%311%21%12%1
1980
21st to endNight
48%38%21%15%4
2118
April1st to 10thNight
51%48%23%12%3
1800
11th to 20thNight
47%311%18%18%2
1775
21st to endNight
48%411%18%16%3
1706
May1st to 10thNight
47%39%20%16%4
1499
11th to 20thNight
39%5%10%24%17%3
1416
21st to endNight
36%414%24%17%4
1551
June1st to 10thNight
43%6%11%24%14%3
1440
11th to 20thNight
37%412%22%22%3
1440
21st to endNight
41%6%12%24%16%1
1440
July1st to 10thNight
31%5%11%26%25%2
1400
11th to 20thNight
35%412%31%17%1
1392
21st to endNight
33%5%13%33%14%2
1486
August1st to 10thNight
35%417%31%12%
1600
11th to 20thNight
37%5%17%27%14%1
1598
21st to endNight
34%5%14%33%13%1
1958
September1st to 10thNight
38%414%30%12%2
1800
11th to 20thNight
34%412%32%17%1
1800
21st to endNight
42%5%12%28%13%1
2062
October1st to 10thNight
52%410%21%12%1
2160
11th to 20thNight
56%414%19%7%
2160
21st to endNight
60%412%14%10%1
2425
November1st to 10thNight
53%411%19%11%2
2416
11th to 20thNight
57%411%17%9%1
2660
21st to endNight
66%313%13%4
2660
December1st to 10thNight
76%39%10%2
2660
11th to 20thNight
70%411%10%4
3288
21st to endNight
74%213%9%2
4884

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 10thDay
23%13%23%28%9%3
180
11th to 20thDay
30%11%29%22%8%1
180
21st to endDay
25%9%24%29%12%1
291
February1st to 10thDay
26%13%30%26%5%
240
11th to 20thDay
21%8%29%35%5%1
240
21st to endDay
29%11%26%29%4
315
March1st to 10thDay
21%7%28%34%9%1
420
11th to 20thDay
22%7%29%31%10%1
420
21st to endDay
28%325%29%12%3
462
April1st to 10thDay
19%7%23%35%13%3
420
11th to 20thDay
23%323%27%18%6%
412
21st to endDay
24%419%35%15%3
420
May1st to 10thDay
22%213%35%23%5%
423
11th to 20thDay
15%213%36%25%8%
447
21st to endDay
15%17%38%28%12%
485
June1st to 10thDay
18%110%35%29%7%
450
11th to 20thDay
14%111%31%36%8%
450
21st to endDay
18%9%34%31%7%
450
July1st to 10thDay
11%15%30%40%13%
445
11th to 20thDay
14%19%29%39%10%
444
21st to endDay
12%19%39%32%7%
488
August1st to 10thDay
14%17%28%39%11%
446
11th to 20thDay
12%19%28%38%13%
439
21st to endDay
13%211%30%35%9%
495
September1st to 10thDay
15%210%32%30%12%
450
11th to 20thDay
12%11%33%26%18%
450
21st to endDay
17%214%32%26%9%
450
October1st to 10thDay
25%416%25%21%10%
450
11th to 20thDay
24%7%25%26%14%4
450
21st to endDay
33%5%22%27%12%1
469
November1st to 10thDay
22%12%23%25%17%1
351
11th to 20thDay
24%11%24%28%11%2
180
21st to endDay
28%7%31%24%8%2
180
December1st to 10thDay
32%9%25%25%8%1
180
11th to 20thDay
26%17%33%19%42
180
21st to endDay
37%9%30%21%3
198
January1st to 10thNight
33%12%30%17%8%
760
11th to 20thNight
30%12%28%22%8%
760
21st to endNight
25%10%28%27%9%1
835
February1st to 10thNight
27%13%32%23%5%
720
11th to 20thNight
25%10%34%23%8%
703
21st to endNight
24%8%37%25%5%
592
March1st to 10thNight
22%8%30%31%9%
720
11th to 20thNight
25%9%27%30%9%2
720
21st to endNight
22%428%30%14%3
792
April1st to 10thNight
24%424%34%12%1
720
11th to 20thNight
22%423%35%14%3
711
21st to endNight
24%320%33%17%3
626
May1st to 10thNight
24%16%31%23%6%
419
11th to 20thNight
15%214%44%22%3
354
21st to endNight
11%212%39%28%8%
389
June1st to 10thNight
15%311%39%27%5%
360
11th to 20thNight
11%213%38%31%6%
360
21st to endNight
17%112%34%31%5%
360
July1st to 10thNight
7%29%35%37%9%
350
11th to 20thNight
11%11%37%33%8%
348
21st to endNight
11%19%43%31%6%
394
August1st to 10thNight
12%19%36%34%8%
537
11th to 20thNight
13%211%34%32%9%
534
21st to endNight
12%213%34%33%6%
770
September1st to 10thNight
16%214%30%31%8%
720
11th to 20thNight
16%213%29%29%11%
720
21st to endNight
18%418%28%23%9%
720
October1st to 10thNight
24%5%21%25%18%7%
720
11th to 20thNight
25%7%26%28%12%2
720
21st to endNight
31%6%27%26%9%1
792
November1st to 10thNight
24%7%25%27%14%2
740
11th to 20thNight
25%10%30%24%8%2
760
21st to endNight
33%9%26%23%7%1
760
December1st to 10thNight
37%13%26%18%5%1
760
11th to 20thNight
28%13%34%19%6%1
760
21st to endNight
37%11%30%18%5%
836
Page generated at 2024-01-28 05:26:35. Version ac07

Copyright 2024 Attilla Danko


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