Auburn
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Auburn 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
68%
23442
29%
74760
27%
23399
72%
23399
40%
40009

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
53%
756
16%
2646
16%
756
55%
756
24%
1651
January11th to 20thNight
58%
744
21%
2466
21%
744
62%
744
27%
1508
January21st to endNight
54%
792
24%
2574
23%
792
59%
792
28%
1575
February1st to 10thNight
58%
720
26%
2340
26%
720
62%
720
31%
1368
February11th to 20thNight
56%
700
27%
2155
25%
700
63%
700
32%
1268
February21st to endNight
55%
592
26%
1776
25%
592
60%
592
32%
1076
March1st to 10thNight
47%
720
16%
2106
16%
720
50%
720
22%
1463
March11th to 20thNight
54%
720
23%
1980
20%
720
58%
720
30%
1287
March21st to endNight
52%
792
19%
2090
12%
792
57%
792
30%
1396
April1st to 10thNight
59%
720
22%
1800
13%
720
62%
720
34%
1181
April11th to 20thNight
60%
711
26%
1779
13%
711
64%
711
41%
1085
April21st to endNight
69%
720
27%
1800
14%
720
72%
720
51%
1015
May1st to 10thNight
66%
666
28%
1746
18%
666
69%
666
50%
951
May11th to 20thNight
75%
354
32%
1416
35%
354
79%
354
46%
588
May21st to endNight
76%
388
28%
1552
32%
388
81%
388
44%
653
June1st to 10thNight
73%
360
27%
1440
33%
360
77%
360
44%
621
June11th to 20thNight
81%
360
36%
1440
44%
360
88%
360
63%
494
June21st to endNight
86%
360
36%
1440
47%
360
91%
360
64%
486
July1st to 10thNight
93%
350
38%
1400
50%
350
95%
350
78%
419
July11th to 20thNight
93%
348
40%
1392
52%
348
93%
348
72%
442
July21st to endNight
91%
565
40%
1650
37%
534
91%
534
71%
660
August1st to 10thNight
88%
537
38%
1602
32%
534
89%
534
66%
679
August11th to 20thNight
92%
678
40%
1746
27%
678
92%
678
78%
785
August21st to endNight
92%
792
44%
1980
28%
792
93%
792
82%
885
September1st to 10thNight
91%
720
46%
1800
32%
720
92%
720
83%
798
September11th to 20thNight
84%
720
45%
1800
34%
720
87%
720
71%
863
September21st to endNight
82%
720
43%
2011
39%
720
87%
720
68%
902
October1st to 10thNight
77%
720
32%
2160
33%
720
81%
720
55%
1014
October11th to 20thNight
77%
720
39%
2160
42%
720
81%
720
56%
1011
October21st to endNight
73%
792
39%
2376
38%
792
79%
792
55%
1121
November1st to 10thNight
67%
740
28%
2373
30%
740
71%
740
38%
1292
November11th to 20thNight
67%
760
29%
2470
28%
760
73%
760
39%
1308
November21st to endNight
62%
760
28%
2596
28%
760
67%
760
37%
1381
December1st to 10thNight
57%
760
23%
2660
23%
760
62%
760
29%
1512
December11th to 20thNight
51%
760
20%
3223
23%
759
55%
759
17%
2205
December21st to endNight
46%
825
14%
4815
19%
817
52%
817
13%
3066

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
10%313323345%64%
74773
Night
12%413323345%59%
75054
TransparencyDay
24%38%19%24%22%
74486
Night
28%38%19%22%20%
74862
SeeingDay
11%6%20%32%24%6%
14033
Night
13%311%37%31%6%
23462

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
24%7%35%33435%6%37%
1519
11th to 20thDay
18%424434346%49%
1616
21st to endDay
20%7%2432445%8%42%
1782
February1st to 10thDay
21%41432445%5%47%
1620
11th to 20thDay
18%5%24423436%49%
1691
21st to endDay
19%6%25%232345%48%
1480
March1st to 10thDay
20%7%25%6%3445%6%38%
1850
11th to 20thDay
22%5%3443435%7%40%
1980
21st to endDay
18%6%244245%47%44%
2264
April1st to 10thDay
17%6%334245%5%6%46%
2160
11th to 20thDay
14%31341345%6%56%
2129
21st to endDay
10%322223447%61%
2160
May1st to 10thDay
7%313413336%65%
2210
11th to 20thDay
5%313323446%66%
2477
21st to endDay
7%21332345%6%64%
2723
June1st to 10thDay
6%312323347%67%
2520
11th to 20thDay
211221223481%
2520
21st to endDay
211111212384%
2520
July1st to 10thDay
111122288%
2520
11th to 20thDay
111111122387%
2520
21st to endDay
111121223483%
2567
August1st to 10thDay
31111122384%
2328
11th to 20thDay
11111123387%
2156
21st to endDay
111111292%
2376
September1st to 10thDay
2111112388%
2160
11th to 20thDay
411221233477%
2160
21st to endDay
4212212225%79%
1946
October1st to 10thDay
5%212422245%71%
1800
11th to 20thDay
7%21221334469%
1800
21st to endDay
8%423323345%65%
1980
November1st to 10thDay
13%41343345%7%54%
1706
11th to 20thDay
14%313424347%53%
1710
21st to endDay
13%423324447%55%
1581
December1st to 10thDay
17%425%433436%49%
1520
11th to 20thDay
31%8%35%423345%32%
1928
21st to endDay
17%7%25%5%35%5%7%8%37%
2794
January1st to 10thNight
23%6%2432335%8%41%
2646
11th to 20thNight
16%6%245%25%5%46%46%
2466
21st to endNight
19%5%25%423446%46%
2574
February1st to 10thNight
20%423323335%52%
2340
11th to 20thNight
16%42442445%8%48%
2155
21st to endNight
19%6%24323435%50%
1776
March1st to 10thNight
23%8%25%5%33345%39%
2106
11th to 20thNight
21%5%2332445%7%44%
1980
21st to endNight
20%423434446%46%
2090
April1st to 10thNight
15%5%35%4335%46%48%
1800
11th to 20thNight
13%414323446%55%
1779
21st to endNight
8%322223447%63%
1800
May1st to 10thNight
8%313223445%65%
1746
11th to 20thNight
7%213213348%66%
1416
21st to endNight
6%21232345%7%66%
1552
June1st to 10thNight
6%212322436%67%
1440
11th to 20thNight
1112213226%79%
1440
21st to endNight
211111223382%
1440
July1st to 10thNight
1111212388%
1440
11th to 20thNight
21111212387%
1440
21st to endNight
122212245%80%
1747
August1st to 10thNight
221222223379%
1611
11th to 20thNight
111211223483%
1746
21st to endNight
111111112287%
1980
September1st to 10thNight
11111112388%
1800
11th to 20thNight
322112225%80%
1800
21st to endNight
311122233479%
2011
October1st to 10thNight
6%21232323373%
2160
11th to 20thNight
7%212212335%72%
2160
21st to endNight
7%212312236%69%
2376
November1st to 10thNight
14%42322335%7%55%
2373
11th to 20thNight
12%41332435%7%57%
2470
21st to endNight
14%423323346%57%
2596
December1st to 10thNight
20%413323345%51%
2660
11th to 20thNight
32%7%3431335%7%33%
3276
21st to endNight
21%6%36%6%45%45%6%35%
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
48%411%22%11%4
1519
11th to 20thDay
39%310%17%17%14%
1616
21st to endDay
43%49%16%19%9%
1782
February1st to 10thDay
39%310%20%17%10%
1620
11th to 20thDay
37%310%20%21%8%
1700
21st to endDay
40%39%23%17%7%
1480
March1st to 10thDay
48%5%10%16%17%4
1850
11th to 20thDay
44%49%23%16%5%
1980
21st to endDay
40%6%13%21%16%4
2264
April1st to 10thDay
38%5%11%24%16%6%
2160
11th to 20thDay
29%5%12%26%22%6%
2132
21st to endDay
24%413%29%27%4
2160
May1st to 10thDay
22%311%26%30%9%
2210
11th to 20thDay
20%49%30%26%11%
2480
21st to endDay
21%5%14%30%24%6%
2724
June1st to 10thDay
19%310%26%29%13%
2520
11th to 20thDay
9%28%21%34%26%
2520
21st to endDay
8%1214%36%39%
2520
July1st to 10thDay
5%239%26%56%
2451
11th to 20thDay
7%2311%25%53%
2445
21st to endDay
8%217%24%57%
2424
August1st to 10thDay
8%2311%29%48%
2312
11th to 20thDay
5%1110%33%49%
2156
21st to endDay
41110%35%48%
2376
September1st to 10thDay
5%128%28%56%
2160
11th to 20thDay
13%3421%35%24%
2160
21st to endDay
12%2419%34%29%
1946
October1st to 10thDay
17%36%19%28%28%
1800
11th to 20thDay
18%46%20%24%28%
1800
21st to endDay
23%37%19%26%22%
1980
November1st to 10thDay
29%5%9%21%22%14%
1706
11th to 20thDay
33%410%23%23%8%
1710
21st to endDay
30%410%20%24%11%
1581
December1st to 10thDay
39%49%20%19%9%
1520
11th to 20thDay
55%49%13%14%5%
1928
21st to endDay
44%5%18%19%10%4
2794
January1st to 10thNight
44%412%22%11%7%
2646
11th to 20thNight
39%5%11%15%15%15%
2466
21st to endNight
40%410%14%22%11%
2574
February1st to 10thNight
37%27%21%20%12%
2340
11th to 20thNight
35%48%22%22%9%
2157
21st to endNight
36%5%8%24%20%8%
1776
March1st to 10thNight
49%5%8%18%15%5%
2106
11th to 20thNight
40%5%8%22%19%7%
1980
21st to endNight
40%6%10%21%16%7%
2090
April1st to 10thNight
38%5%13%18%20%7%
1800
11th to 20thNight
30%5%12%25%17%11%
1779
21st to endNight
22%5%12%32%23%7%
1800
May1st to 10thNight
21%5%11%20%30%12%
1746
11th to 20thNight
19%312%31%23%12%
1416
21st to endNight
18%5%15%31%25%6%
1552
June1st to 10thNight
19%5%10%27%28%11%
1440
11th to 20thNight
10%37%21%32%28%
1440
21st to endNight
10%2313%33%39%
1440
July1st to 10thNight
5%2211%27%53%
1400
11th to 20thNight
7%2211%23%56%
1392
21st to endNight
9%328%24%54%
1650
August1st to 10thNight
12%2214%26%45%
1602
11th to 20thNight
8%2110%32%48%
1746
21st to endNight
7%1110%30%51%
1980
September1st to 10thNight
6%228%29%55%
1800
11th to 20thNight
12%25%19%40%24%
1800
21st to endNight
11%2419%30%34%
2011
October1st to 10thNight
18%35%17%27%30%
2160
11th to 20thNight
17%3419%25%31%
2160
21st to endNight
18%26%21%27%25%
2376
November1st to 10thNight
30%49%22%18%17%
2373
11th to 20thNight
28%49%26%22%10%
2470
21st to endNight
30%37%22%22%15%
2596
December1st to 10thNight
36%410%19%18%13%
2660
11th to 20thNight
52%37%16%15%7%
3276
21st to endNight
51%413%18%11%4
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
41%6%19%17%15%2
180
11th to 20thDay
23%6%17%29%19%5%
304
21st to endDay
22%7%21%24%21%6%
374
February1st to 10thDay
23%7%20%26%21%3
340
11th to 20thDay
20%13%23%25%16%2
389
21st to endDay
21%12%25%28%12%2
346
March1st to 10thDay
27%11%28%23%10%2
420
11th to 20thDay
24%11%25%23%13%4
420
21st to endDay
20%12%30%23%13%1
462
April1st to 10thDay
21%10%29%25%13%3
420
11th to 20thDay
16%13%30%25%13%3
412
21st to endDay
10%10%24%29%22%6%
420
May1st to 10thDay
9%9%29%29%19%5%
423
11th to 20thDay
7%10%26%27%23%7%
448
21st to endDay
7%8%20%29%27%9%
485
June1st to 10thDay
6%7%21%34%24%9%
450
11th to 20thDay
46%24%39%22%6%
450
21st to endDay
1418%41%28%9%
450
July1st to 10thDay
1112%49%31%7%
446
11th to 20thDay
110%42%39%7%
444
21st to endDay
112%43%34%10%
487
August1st to 10thDay
3213%42%33%7%
447
11th to 20thDay
1116%41%31%10%
437
21st to endDay
112%42%37%8%
495
September1st to 10thDay
2214%46%30%7%
450
11th to 20thDay
6%320%38%28%5%
450
21st to endDay
4422%38%28%5%
450
October1st to 10thDay
47%24%30%29%6%
450
11th to 20thDay
7%415%32%33%8%
450
21st to endDay
11%6%17%30%28%7%
495
November1st to 10thDay
18%5%14%27%29%7%
302
11th to 20thDay
11%418%29%27%10%
270
21st to endDay
12%419%32%26%8%
209
December1st to 10thDay
21%6%15%26%22%11%
180
11th to 20thDay
17%9%23%23%17%11%
180
21st to endDay
20%9%22%24%20%5%
198
January1st to 10thNight
25%314%29%22%8%
760
11th to 20thNight
17%312%39%23%6%
744
21st to endNight
22%313%33%23%7%
792
February1st to 10thNight
21%312%36%24%5%
720
11th to 20thNight
18%415%36%22%5%
704
21st to endNight
21%5%14%40%17%3
592
March1st to 10thNight
26%6%12%32%20%4
720
11th to 20thNight
23%414%30%26%4
720
21st to endNight
20%5%16%36%20%3
792
April1st to 10thNight
16%412%41%25%3
720
11th to 20thNight
13%5%16%35%25%6%
711
21st to endNight
9%413%39%29%7%
720
May1st to 10thNight
9%415%40%28%4
666
11th to 20thNight
8%210%38%38%4
354
21st to endNight
8%210%38%40%3
389
June1st to 10thNight
7%312%36%37%5%
360
11th to 20thNight
3111%43%39%3
360
21st to endNight
316%43%44%4
360
July1st to 10thNight
1442%52%2
350
11th to 20thNight
1344%48%3
348
21st to endNight
1333%55%8%
565
August1st to 10thNight
31439%48%5%
537
11th to 20thNight
1442%45%8%
678
21st to endNight
1337%54%5%
792
September1st to 10thNight
25%36%51%7%
720
11th to 20thNight
418%36%43%8%
720
21st to endNight
3210%38%36%11%
720
October1st to 10thNight
6%210%40%33%9%
720
11th to 20thNight
8%28%36%39%6%
720
21st to endNight
7%213%34%30%13%
792
November1st to 10thNight
15%310%33%30%9%
740
11th to 20thNight
13%311%40%27%7%
760
21st to endNight
15%214%38%24%8%
760
December1st to 10thNight
20%312%36%21%7%
760
11th to 20thNight
29%311%33%20%4
760
21st to endNight
26%316%32%18%4
836
Page generated at 2024-01-13 16:28:27. Version ac07

Copyright 2024 Attilla Danko


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