Pinhey's Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pinhey's Point clear sky chart from 2005-11-05 to 2017-09-16.

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
30%
14646
13%
46844
9%
14614
37%
14614
17%
33029

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
17%
720
7%
2506
4%
716
21%
716
7%
2015
January16th to endNight
22%
768
12%
2637
6%
768
29%
768
12%
1950
February1st to 15thNight
18%
704
11%
2287
4%
701
26%
701
11%
1726
February16th to endNight
23%
631
14%
1954
6%
631
34%
631
13%
1441
March1st to 15thNight
20%
720
13%
2094
7%
720
28%
720
15%
1557
March16th to endNight
29%
768
20%
2037
10%
768
37%
768
22%
1387
April1st to 15thNight
24%
718
16%
1796
6%
718
29%
718
19%
1312
April16th to endNight
30%
642
17%
1722
8%
642
36%
642
22%
1201
May1st to 15thNight
35%
360
17%
1440
17%
360
44%
360
17%
935
May16th to endNight
37%
375
13%
1497
11%
374
48%
374
19%
956
June1st to 15thNight
37%
360
10%
1440
9%
360
46%
360
17%
938
June16th to endNight
44%
360
8%
1440
11%
360
49%
360
19%
899
July1st to 15thNight
53%
340
15%
1360
20%
340
60%
340
28%
735
July16th to endNight
57%
376
14%
1418
17%
354
61%
354
28%
785
August1st to 15thNight
55%
446
15%
1517
13%
444
60%
444
26%
919
August16th to endNight
51%
705
20%
1851
10%
705
56%
705
36%
1141
September1st to 15thNight
46%
720
16%
1800
8%
720
48%
720
30%
1226
September16th to endNight
47%
661
22%
1806
14%
661
52%
661
32%
1152
October1st to 15thNight
32%
660
18%
1980
11%
660
42%
660
20%
1371
October16th to endNight
26%
704
12%
2197
7%
704
33%
704
13%
1660
November1st to 15thNight
27%
700
16%
2337
12%
700
35%
700
17%
1638
November16th to endNight
19%
720
10%
2520
6%
720
25%
720
10%
1938
December1st to 15thNight
19%
720
7%
2520
3%
720
24%
720
9%
2003
December16th to endNight
14%
768
10%
2688
4%
768
22%
768
8%
2144

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
17%8%36%5%3445%6%33%
47925
Night
18%9%36%5%34446%33%
47013
Cloud CoverDay
20%7%36%5%34446%33%
47934
Night
19%9%36%5%34445%33%
47019
TransparencyDay
50%5%12%20%9%1
47612
Night
52%411%20%10%
46844
SeeingDay
21%12%28%21%12%3
5462
Night
23%10%27%26%10%
14646

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
21%14%7%9%5%24435%21%
1432
16th to endDay
14%14%5%9%7%4435%5%24%
1584
February1st to 15thDay
12%14%411%7%46%43425%
1575
16th to endDay
17%13%48%7%335%45%26%
1518
March1st to 15thDay
17%11%37%7%46%44428%
1853
16th to endDay
15%7%46%5%2335%5%40%
2187
April1st to 15thDay
22%8%45%423246%34%
2152
16th to endDay
20%7%26%5%2444437%
2249
May1st to 15thDay
19%7%36%5%34346%33%
2511
16th to endDay
17%6%25%6%45%5%5%6%35%
2618
June1st to 15thDay
20%6%35%5%45%45%8%30%
2520
16th to endDay
17%5%26%5%36%6%6%7%31%
2520
July1st to 15thDay
13%425%5%35%5%6%8%38%
2520
16th to endDay
11%5%25%5%35%6%6%9%38%
2654
August1st to 15thDay
10%5%26%6%35%6%5%8%38%
2431
16th to endDay
11%425%435%5%6%8%42%
2339
September1st to 15thDay
15%5%25%424448%42%
2160
16th to endDay
15%424433348%44%
1843
October1st to 15thDay
21%6%36%5%34446%34%
1650
16th to endDay
27%7%36%6%34425%26%
1675
November1st to 15thDay
15%8%45%5%35%5%6%7%32%
1518
16th to endDay
24%11%47%6%34445%23%
1440
December1st to 15thDay
21%14%5%8%7%35%45%5%17%
1440
16th to endDay
24%14%5%9%7%3334420%
1536
January1st to 15thNight
19%15%6%10%7%35%435%18%
2506
16th to endNight
14%15%5%8%7%35%335%27%
2637
February1st to 15thNight
13%12%5%12%7%45%446%24%
2285
16th to endNight
17%10%5%7%7%34445%28%
1954
March1st to 15thNight
18%10%5%8%6%34335%29%
2081
16th to endNight
15%7%35%5%2434442%
2037
April1st to 15thNight
22%8%24433345%35%
1796
16th to endNight
18%6%35%5%3435%5%38%
1722
May1st to 15thNight
21%7%34434346%36%
1440
16th to endNight
15%6%35%5%245%5%6%37%
1495
June1st to 15thNight
17%6%25%6%3445%8%34%
1440
16th to endNight
17%5%24435%45%8%37%
1440
July1st to 15thNight
10%314425%5%48%47%
1440
16th to endNight
10%423435%45%8%45%
1514
August1st to 15thNight
10%5%25%43445%9%42%
1527
16th to endNight
9%323425%45%7%50%
1851
September1st to 15thNight
14%5%25%5%3445%6%43%
1800
16th to endNight
18%424423235%49%
1806
October1st to 15thNight
20%7%25%424445%36%
1980
16th to endNight
25%9%26%5%44446%26%
2197
November1st to 15thNight
20%9%36%6%24345%33%
2337
16th to endNight
23%10%48%6%34445%24%
2520
December1st to 15thNight
22%14%5%7%6%345%45%19%
2520
16th to endNight
24%15%5%8%6%3433420%
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
21%13%6%9%5%245%35%21%
1432
16th to endDay
14%14%48%7%45%45%5%25%
1584
February1st to 15thDay
13%13%5%10%7%46%44425%
1575
16th to endDay
17%13%47%7%245%45%26%
1518
March1st to 15thDay
24%8%36%6%35%44328%
1863
16th to endDay
22%6%345%1434438%
2186
April1st to 15thDay
22%7%35%422336%37%
2152
16th to endDay
19%6%35%424445%39%
2249
May1st to 15thDay
24%6%26%424345%34%
2511
16th to endDay
23%5%145%33445%36%
2618
June1st to 15thDay
25%5%26%5%35%447%28%
2520
16th to endDay
21%5%25%5%35%6%6%7%29%
2520
July1st to 15thDay
13%425%5%26%5%7%8%39%
2520
16th to endDay
11%4346%35%5%6%9%38%
2654
August1st to 15thDay
21%4145%345%5%6%36%
2431
16th to endDay
20%41442445%7%41%
2339
September1st to 15thDay
15%5%15%43445%7%42%
2160
16th to endDay
15%5%23433448%43%
1843
October1st to 15thDay
20%6%36%434447%34%
1650
16th to endDay
26%7%37%7%25%435%26%
1675
November1st to 15thDay
19%7%36%5%25%5%5%5%32%
1518
16th to endDay
25%10%47%6%34346%23%
1440
December1st to 15thDay
21%13%5%7%8%35%5%46%18%
1440
16th to endDay
24%14%5%8%6%3433321%
1536
January1st to 15thNight
18%15%6%10%7%45%44418%
2506
16th to endNight
13%15%5%8%6%44446%26%
2637
February1st to 15thNight
14%12%5%11%6%35%445%25%
2278
16th to endNight
17%11%47%7%34345%29%
1954
March1st to 15thNight
27%8%46%5%3333429%
2094
16th to endNight
22%6%25%42333341%
2037
April1st to 15thNight
22%8%34423335%37%
1796
16th to endNight
18%6%25%433445%40%
1722
May1st to 15thNight
24%6%24434445%35%
1440
16th to endNight
18%6%35%5%2345%7%38%
1495
June1st to 15thNight
20%6%25%6%3445%7%33%
1440
16th to endNight
19%425%426%45%6%37%
1440
July1st to 15thNight
10%324325%5%5%9%46%
1440
16th to endNight
9%4244345%6%8%46%
1514
August1st to 15thNight
14%42442345%8%44%
1527
16th to endNight
15%31342445%5%49%
1851
September1st to 15thNight
14%5%35%5%34445%43%
1800
16th to endNight
17%425%322235%48%
1806
October1st to 15thNight
20%7%25%5%24445%37%
1980
16th to endNight
24%9%26%5%3435%5%27%
2197
November1st to 15thNight
24%8%35%6%24345%32%
2337
16th to endNight
27%9%47%6%33335%24%
2520
December1st to 15thNight
23%13%47%5%35%445%21%
2520
16th to endNight
24%15%5%7%6%2433421%
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
64%49%14%5%
1433
16th to endDay
61%411%14%8%
1584
February1st to 15thDay
62%311%16%4
1577
16th to endDay
58%410%15%9%1
1518
March1st to 15thDay
58%411%16%7%1
1863
16th to endDay
44%49%20%15%5%
2187
April1st to 15thDay
52%27%20%13%2
2152
16th to endDay
49%37%20%16%3
2249
May1st to 15thDay
51%47%21%13%2
2511
16th to endDay
48%5%11%20%12%1
2622
June1st to 15thDay
51%5%12%21%8%
2520
16th to endDay
47%5%13%20%10%1
2520
July1st to 15thDay
38%6%15%27%12%
2371
16th to endDay
41%6%18%24%9%
2487
August1st to 15thDay
41%7%17%23%10%
2417
16th to endDay
37%5%16%29%10%
2339
September1st to 15thDay
41%5%13%27%11%
2160
16th to endDay
39%5%13%33%9%
1843
October1st to 15thDay
49%413%21%9%
1650
16th to endDay
60%413%14%6%
1675
November1st to 15thDay
49%5%15%20%8%
1518
16th to endDay
61%5%12%12%6%1
1440
December1st to 15thDay
67%5%11%12%2
1440
16th to endDay
67%311%11%5%
1536
January1st to 15thNight
68%49%12%5%
2506
16th to endNight
59%39%17%8%
2637
February1st to 15thNight
61%311%16%5%
2287
16th to endNight
57%49%18%9%
1954
March1st to 15thNight
57%310%19%8%
2094
16th to endNight
45%39%20%16%4
2037
April1st to 15thNight
52%37%19%16%1
1796
16th to endNight
47%47%18%17%3
1722
May1st to 15thNight
49%37%20%15%3
1440
16th to endNight
45%5%12%20%14%2
1497
June1st to 15thNight
47%5%13%22%9%1
1440
16th to endNight
43%6%12%22%15%
1440
July1st to 15thNight
32%5%13%31%15%1
1360
16th to endNight
34%5%16%28%15%
1418
August1st to 15thNight
37%6%17%25%12%
1517
16th to endNight
32%5%15%34%11%
1851
September1st to 15thNight
41%5%11%29%11%1
1800
16th to endNight
39%311%35%10%
1806
October1st to 15thNight
48%5%10%23%11%
1980
16th to endNight
59%413%16%6%
2197
November1st to 15thNight
52%413%18%10%
2337
16th to endNight
62%5%10%16%4
2520
December1st to 15thNight
65%5%13%13%2
2520
16th to endNight
68%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
30%26%23%15%5%
60
16th to endDay
30%15%37%13%2
72
February1st to 15thDay
30%26%32%11%
90
16th to endDay
31%23%23%16%4
177
March1st to 15thDay
25%16%32%21%4
270
16th to endDay
22%17%30%16%11%2
288
April1st to 15thDay
25%22%26%17%7%
270
16th to endDay
22%16%28%17%11%2
270
May1st to 15thDay
29%10%29%17%8%4
288
16th to endDay
18%15%32%22%10%1
331
June1st to 15thDay
26%8%31%22%8%2
315
16th to endDay
17%9%33%23%13%1
315
July1st to 15thDay
16%5%27%30%14%5%
305
16th to endDay
12%329%28%19%6%
326
August1st to 15thDay
10%6%25%32%17%6%
313
16th to endDay
12%5%25%26%19%10%
332
September1st to 15thDay
18%7%22%18%22%11%
315
16th to endDay
18%6%28%19%17%9%
257
October1st to 15thDay
22%10%25%25%14%2
255
16th to endDay
31%16%24%19%8%
257
November1st to 15thDay
18%13%29%23%13%1
172
16th to endDay
33%13%33%18%1
60
December1st to 15thDay
25%18%38%15%3
60
16th to endDay
39%20%35%4
64
January1st to 15thNight
26%15%30%22%4
720
16th to endNight
22%12%33%25%5%
768
February1st to 15thNight
20%14%36%23%5%
704
16th to endNight
24%16%29%23%5%
631
March1st to 15thNight
26%13%32%25%3
720
16th to endNight
21%15%27%27%9%
768
April1st to 15thNight
28%12%29%25%4
718
16th to endNight
23%14%28%25%8%
642
May1st to 15thNight
26%6%24%31%9%1
360
16th to endNight
19%5%31%29%13%
375
June1st to 15thNight
20%6%28%31%11%
360
16th to endNight
20%324%36%14%1
360
July1st to 15thNight
10%127%40%18%
340
16th to endNight
10%322%45%17%1
376
August1st to 15thNight
14%219%38%23%1
446
16th to endNight
10%423%36%22%2
705
September1st to 15thNight
18%424%28%21%2
720
16th to endNight
20%5%22%28%20%2
661
October1st to 15thNight
26%8%25%25%12%1
660
16th to endNight
30%12%24%25%7%
704
November1st to 15thNight
24%10%29%23%11%
700
16th to endNight
30%15%25%19%8%
720
December1st to 15thNight
30%14%28%22%3
720
16th to endNight
33%13%29%17%4
768
Page generated at 2017-09-17 12:05:42. Version ac04

Copyright 2017 A. Danko


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