Pine Flat Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pine Flat Observatory clear sky chart from 2005-11-06 to 2024-01-16.

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
66%
23963
31%
74604
27%
23918
71%
23918
44%
38480

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
51%
756
24%
2646
22%
756
58%
756
28%
1523
January11th to 20thNight
54%
744
29%
2502
24%
744
65%
744
35%
1356
January21st to endNight
49%
792
30%
2534
24%
792
59%
792
31%
1473
February1st to 10thNight
50%
720
28%
2160
22%
720
58%
720
32%
1284
February11th to 20thNight
56%
700
31%
2099
26%
700
64%
700
38%
1170
February21st to endNight
49%
592
24%
1776
22%
592
55%
592
29%
1114
March1st to 10thNight
50%
720
21%
2160
18%
720
57%
720
30%
1336
March11th to 20thNight
57%
720
20%
2093
19%
720
60%
720
31%
1290
March21st to endNight
52%
792
20%
1980
13%
792
57%
792
34%
1293
April1st to 10thNight
55%
720
26%
1800
15%
720
60%
720
38%
1121
April11th to 20thNight
56%
711
29%
1779
15%
711
60%
711
44%
1038
April21st to endNight
60%
720
30%
1800
16%
720
64%
720
51%
983
May1st to 10thNight
60%
637
30%
1717
17%
637
64%
637
48%
909
May11th to 20thNight
63%
531
34%
1595
26%
531
66%
531
50%
759
May21st to endNight
59%
542
30%
1706
23%
542
64%
542
47%
801
June1st to 10thNight
75%
360
32%
1440
35%
360
81%
360
50%
571
June11th to 20thNight
84%
360
39%
1440
45%
360
88%
360
68%
462
June21st to endNight
88%
360
41%
1440
49%
360
91%
360
74%
447
July1st to 10thNight
95%
350
39%
1400
48%
350
95%
350
73%
438
July11th to 20thNight
95%
348
41%
1392
50%
348
95%
348
68%
463
July21st to endNight
88%
570
37%
1655
32%
539
89%
539
64%
714
August1st to 10thNight
86%
716
37%
1780
24%
712
86%
712
75%
830
August11th to 20thNight
93%
712
41%
1780
26%
712
93%
712
84%
782
August21st to endNight
91%
792
45%
1980
30%
792
92%
792
80%
897
September1st to 10thNight
89%
720
46%
1800
33%
720
91%
720
80%
814
September11th to 20thNight
85%
720
47%
1898
38%
720
89%
720
78%
820
September21st to endNight
83%
720
45%
1980
39%
720
89%
720
75%
847
October1st to 10thNight
77%
720
38%
1984
34%
720
82%
720
61%
945
October11th to 20thNight
74%
720
39%
2160
38%
720
80%
720
56%
1004
October21st to endNight
73%
792
42%
2420
40%
792
80%
792
56%
1105
November1st to 10thNight
68%
740
32%
2405
33%
740
74%
740
44%
1201
November11th to 20thNight
66%
760
34%
2470
30%
760
76%
760
47%
1179
November21st to endNight
57%
760
29%
2470
26%
760
65%
760
37%
1326
December1st to 10thNight
51%
760
29%
2470
21%
760
62%
760
35%
1355
December11th to 20thNight
48%
759
23%
3140
22%
759
58%
759
22%
1965
December21st to endNight
45%
827
15%
4753
22%
817
52%
817
14%
2865

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
6%5%23323346%65%
74841
Night
6%5%23323345%63%
74975
TransparencyDay
21%5%7%19%27%21%
74556
Night
22%6%7%19%26%20%
74782
SeeingDay
12%11%32%30%10%4
14220
Night
10%415%36%29%6%
23983

By Month

Percentage Cloud Cover SW (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
12%6%24434449%49%
1519
11th to 20thDay
8%5%2443345%6%54%
1575
21st to endDay
10%12%35%434446%46%
1820
February1st to 10thDay
11%9%3421335%6%54%
1800
11th to 20thDay
9%11%33423347%51%
1750
21st to endDay
14%12%5%4333336%43%
1480
March1st to 10thDay
13%11%45%5%3445%7%40%
1800
11th to 20thDay
8%9%45%43445%9%45%
1862
21st to endDay
9%13%35%5%23446%46%
2376
April1st to 10thDay
9%8%34423447%52%
2160
11th to 20thDay
9%6%2432345%7%56%
2129
21st to endDay
6%7%23323347%60%
2160
May1st to 10thDay
7%5%1322435%6%62%
2240
11th to 20thDay
6%413323347%64%
2301
21st to endDay
7%423222346%64%
2566
June1st to 10thDay
321332235%7%69%
2520
11th to 20thDay
111121133383%
2520
21st to endDay
111121223285%
2520
July1st to 10thDay
111121223481%
2520
11th to 20thDay
311221333480%
2520
21st to endDay
3212222336%73%
2561
August1st to 10thDay
221121223481%
2149
11th to 20thDay
11111223483%
2122
21st to endDay
11221223384%
2376
September1st to 10thDay
211111235%82%
2160
11th to 20thDay
111121222385%
2062
21st to endDay
211211223382%
1980
October1st to 10thDay
5%5%1232334468%
1972
11th to 20thDay
3213323335%73%
1800
21st to endDay
5%31222334471%
1933
November1st to 10thDay
5%9%23323346%61%
1674
11th to 20thDay
6%413223346%65%
1710
21st to endDay
7%6%343235%46%57%
1710
December1st to 10thDay
7%5%2442445%7%56%
1710
11th to 20thDay
13%10%25%6%36%35%7%41%
1990
21st to endDay
9%11%45%446%5%5%8%41%
2794
January1st to 10thNight
13%7%3433445%8%47%
2646
11th to 20thNight
6%7%334245%6%7%53%
2502
21st to endNight
12%9%34323446%52%
2534
February1st to 10thNight
10%11%34323346%50%
2160
11th to 20thNight
9%10%2321335%6%55%
2098
21st to endNight
12%11%5%5%323345%48%
1776
March1st to 10thNight
10%10%344245%6%7%44%
2160
11th to 20thNight
10%9%3443445%8%47%
2093
21st to endNight
11%12%343245%46%47%
1980
April1st to 10thNight
9%7%24424346%54%
1800
11th to 20thNight
7%7%23324346%59%
1779
21st to endNight
6%6%23213336%66%
1800
May1st to 10thNight
7%5%12323347%64%
1717
11th to 20thNight
6%313322235%70%
1594
21st to endNight
7%322322235%70%
1706
June1st to 10thNight
4322213335%72%
1440
11th to 20thNight
111111222483%
1440
21st to endNight
1111223485%
1440
July1st to 10thNight
11121223484%
1440
11th to 20thNight
2111111235%81%
1440
21st to endNight
221221224477%
1752
August1st to 10thNight
121211223382%
1790
11th to 20thNight
11112225%86%
1780
21st to endNight
11111222386%
1980
September1st to 10thNight
11111122288%
1800
11th to 20thNight
111111123286%
1898
21st to endNight
121111223383%
1980
October1st to 10thNight
4312313345%72%
1984
11th to 20thNight
421331344472%
2160
21st to endNight
441231233374%
2420
November1st to 10thNight
6%7%23313346%61%
2405
11th to 20thNight
5%5%1332345%7%63%
2470
21st to endNight
7%6%35%423446%56%
2470
December1st to 10thNight
8%5%35%423446%55%
2470
11th to 20thNight
15%8%344346%6%7%40%
3209
21st to endNight
8%8%37%7%47%5%6%7%38%
4862

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
31%6%9%22%23%8%
1519
11th to 20thDay
28%7%7%21%23%14%
1575
21st to endDay
39%6%8%15%19%13%
1820
February1st to 10thDay
32%47%20%25%12%
1800
11th to 20thDay
32%5%7%18%25%12%
1760
21st to endDay
40%7%7%21%21%4
1480
March1st to 10thDay
40%9%9%16%18%9%
1800
11th to 20thDay
32%8%12%22%19%7%
1862
21st to endDay
35%9%13%24%14%5%
2376
April1st to 10thDay
31%7%11%27%17%8%
2160
11th to 20thDay
25%7%10%28%22%8%
2132
21st to endDay
23%6%12%33%23%3
2160
May1st to 10thDay
21%5%10%26%31%6%
2240
11th to 20thDay
20%5%8%29%31%8%
2304
21st to endDay
21%5%8%32%30%3
2566
June1st to 10thDay
15%5%10%22%34%14%
2520
11th to 20thDay
8%35%15%42%26%
2520
21st to endDay
7%239%37%41%
2520
July1st to 10thDay
8%2310%28%48%
2451
11th to 20thDay
11%3412%30%40%
2445
21st to endDay
14%46%16%30%31%
2418
August1st to 10thDay
9%238%32%44%
2135
11th to 20thDay
7%2311%37%40%
2122
21st to endDay
8%229%36%44%
2376
September1st to 10thDay
8%2310%31%45%
2160
11th to 20thDay
7%3415%39%33%
2062
21st to endDay
9%3220%36%30%
1980
October1st to 10thDay
18%45%19%24%30%
1972
11th to 20thDay
15%4416%32%30%
1800
21st to endDay
15%5%5%16%30%29%
1933
November1st to 10thDay
21%8%5%17%28%21%
1674
11th to 20thDay
21%48%20%26%21%
1710
21st to endDay
27%5%7%15%24%22%
1710
December1st to 10thDay
26%7%7%19%23%18%
1710
11th to 20thDay
39%8%9%16%16%12%
1990
21st to endDay
37%10%7%22%17%7%
2794
January1st to 10thNight
32%9%6%21%21%10%
2646
11th to 20thNight
24%10%8%22%21%15%
2502
21st to endNight
34%5%8%17%21%15%
2534
February1st to 10thNight
35%46%16%24%15%
2160
11th to 20thNight
29%5%6%18%27%15%
2099
21st to endNight
37%6%8%20%23%6%
1776
March1st to 10thNight
35%8%10%20%18%9%
2160
11th to 20thNight
31%11%10%19%21%8%
2093
21st to endNight
34%8%13%26%15%3
1980
April1st to 10thNight
30%7%11%28%16%8%
1800
11th to 20thNight
24%6%12%29%22%7%
1779
21st to endNight
19%6%11%40%21%3
1800
May1st to 10thNight
19%6%10%32%27%5%
1717
11th to 20thNight
18%38%32%33%5%
1595
21st to endNight
17%5%10%30%33%4
1706
June1st to 10thNight
16%410%22%37%11%
1440
11th to 20thNight
6%48%19%39%24%
1440
21st to endNight
6%2312%40%37%
1440
July1st to 10thNight
6%2310%31%48%
1400
11th to 20thNight
7%35%15%29%41%
1392
21st to endNight
12%36%18%29%32%
1655
August1st to 10thNight
9%2310%33%42%
1780
11th to 20thNight
42314%37%40%
1780
21st to endNight
7%2111%37%42%
1980
September1st to 10thNight
6%3210%34%46%
1800
11th to 20thNight
7%2316%42%30%
1898
21st to endNight
8%3220%36%31%
1980
October1st to 10thNight
14%45%19%28%31%
1984
11th to 20thNight
15%5%318%29%29%
2160
21st to endNight
15%4417%31%29%
2420
November1st to 10thNight
21%7%6%15%31%21%
2405
11th to 20thNight
20%5%7%18%25%25%
2470
21st to endNight
28%6%7%13%25%21%
2470
December1st to 10thNight
28%7%7%17%23%19%
2470
11th to 20thNight
38%10%9%16%15%12%
3209
21st to endNight
36%14%7%21%15%7%
4862

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
27%11%29%29%31
180
11th to 20thDay
22%10%31%26%9%2
265
21st to endDay
17%12%35%26%9%
392
February1st to 10thDay
19%12%33%24%10%2
420
11th to 20thDay
20%17%33%24%5%1
415
21st to endDay
26%15%33%20%5%1
346
March1st to 10thDay
26%15%35%19%5%
420
11th to 20thDay
21%20%28%23%7%2
420
21st to endDay
26%19%34%16%5%
462
April1st to 10thDay
21%18%28%24%8%1
420
11th to 20thDay
25%19%29%20%6%
412
21st to endDay
17%18%30%22%9%4
420
May1st to 10thDay
20%19%29%21%8%3
423
11th to 20thDay
14%17%32%26%8%4
448
21st to endDay
20%10%30%27%9%5%
485
June1st to 10thDay
6%11%35%30%12%5%
450
11th to 20thDay
413%36%31%9%6%
450
21st to endDay
5%12%34%29%13%7%
450
July1st to 10thDay
25%35%38%10%11%
446
11th to 20thDay
2224%45%14%12%
444
21st to endDay
3226%43%14%11%
487
August1st to 10thDay
5%6%36%32%13%9%
447
11th to 20thDay
3434%38%11%9%
437
21st to endDay
1332%43%14%7%
495
September1st to 10thDay
2438%38%14%3
450
11th to 20thDay
310%40%35%11%2
450
21st to endDay
5%9%35%33%16%2
450
October1st to 10thDay
8%12%31%36%11%1
450
11th to 20thDay
6%10%35%36%10%2
450
21st to endDay
9%9%33%31%16%1
448
November1st to 10thDay
12%8%25%39%14%2
270
11th to 20thDay
10%6%30%34%16%3
270
21st to endDay
14%10%26%35%13%3
270
December1st to 10thDay
13%12%34%33%7%1
270
11th to 20thDay
18%8%30%29%15%
210
21st to endDay
24%14%27%26%9%
198
January1st to 10thNight
19%421%33%18%5%
760
11th to 20thNight
11%5%23%36%20%5%
744
21st to endNight
17%424%34%17%3
792
February1st to 10thNight
16%423%35%17%5%
720
11th to 20thNight
17%5%19%35%19%5%
704
21st to endNight
20%6%20%38%14%3
592
March1st to 10thNight
17%6%21%37%15%4
720
11th to 20thNight
16%5%16%33%26%5%
720
21st to endNight
19%6%17%37%18%3
792
April1st to 10thNight
15%6%18%38%21%2
720
11th to 20thNight
13%7%19%35%23%4
711
21st to endNight
12%7%19%34%23%6%
720
May1st to 10thNight
10%5%20%36%26%3
637
11th to 20thNight
8%8%15%35%30%3
531
21st to endNight
13%8%16%35%27%3
544
June1st to 10thNight
6%311%40%37%4
360
11th to 20thNight
2110%45%37%5%
360
21st to endNight
118%46%42%4
360
July1st to 10thNight
1130%60%7%
350
11th to 20thNight
1124%66%8%
348
21st to endNight
2224%59%13%
570
August1st to 10thNight
216%36%47%8%
716
11th to 20thNight
1432%49%13%
712
21st to endNight
2330%51%14%
792
September1st to 10thNight
216%31%48%13%
720
11th to 20thNight
218%39%42%8%
720
21st to endNight
2111%36%40%9%
720
October1st to 10thNight
5%112%43%33%6%
720
11th to 20thNight
6%213%37%34%8%
720
21st to endNight
6%313%36%31%10%
792
November1st to 10thNight
12%212%39%26%8%
740
11th to 20thNight
8%416%42%25%6%
760
21st to endNight
11%322%40%20%4
760
December1st to 10thNight
12%425%36%19%4
760
11th to 20thNight
19%423%36%14%3
760
21st to endNight
18%6%24%36%13%4
836
Page generated at 2024-01-13 06:37:58. Version ac07

Copyright 2024 Attilla Danko


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