KimbleLabs Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the KimbleLabs Observatory clear sky chart from 2005-11-06 to 2025-01-07.

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
40%
25137
16%
101761
13%
24824
46%
24824
17%
67185

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
21%
974
10%
4479
6%
957
28%
957
8%
3495
January11th to 20thNight
18%
811
10%
4159
5%
791
25%
791
7%
3219
January21st to endNight
22%
832
8%
4512
9%
814
28%
814
7%
3489
February1st to 10thNight
25%
760
13%
2371
8%
760
30%
760
14%
1773
February11th to 20thNight
22%
741
14%
2219
7%
740
28%
740
17%
1603
February21st to endNight
20%
628
13%
1884
5%
628
28%
628
15%
1392
March1st to 10thNight
26%
757
17%
3670
9%
745
32%
745
12%
2482
March11th to 20thNight
27%
754
21%
3434
8%
740
35%
740
16%
1910
March21st to endNight
29%
829
10%
3683
7%
814
36%
814
13%
2328
April1st to 10thNight
32%
622
17%
1952
11%
622
41%
622
23%
1309
April11th to 20thNight
36%
563
20%
1820
13%
563
46%
563
24%
1159
April21st to endNight
32%
570
17%
1710
8%
570
41%
570
23%
1154
May1st to 10thNight
33%
565
12%
2787
8%
559
38%
559
11%
2079
May11th to 20thNight
45%
548
13%
2766
11%
541
50%
541
15%
1683
May21st to endNight
56%
608
13%
3039
12%
593
61%
593
21%
1569
June1st to 10thNight
59%
570
18%
1696
15%
570
62%
570
33%
1030
June11th to 20thNight
63%
570
21%
1520
15%
570
67%
570
37%
929
June21st to endNight
63%
570
18%
1520
13%
570
67%
570
36%
932
July1st to 10thNight
62%
542
22%
2293
16%
535
65%
535
23%
1324
July11th to 20thNight
68%
535
19%
2294
17%
533
70%
533
27%
1225
July21st to endNight
66%
609
15%
2829
18%
569
69%
569
20%
1722
August1st to 10thNight
67%
557
21%
2582
20%
544
70%
544
22%
1517
August11th to 20thNight
67%
546
19%
2513
20%
543
70%
543
22%
1488
August21st to endNight
70%
605
20%
2971
22%
605
73%
605
30%
1355
September1st to 10thNight
62%
666
25%
1996
20%
666
66%
666
35%
1167
September11th to 20thNight
68%
760
30%
2090
24%
760
71%
760
41%
1217
September21st to endNight
51%
760
26%
2090
20%
760
55%
760
31%
1329
October1st to 10thNight
57%
760
25%
2211
21%
740
62%
740
33%
1370
October11th to 20thNight
42%
760
19%
2506
17%
740
48%
740
24%
1575
October21st to endNight
36%
836
18%
2999
17%
814
44%
814
18%
2037
November1st to 10thNight
42%
780
24%
2536
19%
780
50%
780
28%
1519
November11th to 20thNight
32%
800
22%
2600
13%
800
44%
800
22%
1694
November21st to endNight
32%
800
17%
2600
13%
800
38%
800
17%
1843
December1st to 10thNight
24%
794
19%
4100
7%
780
33%
780
11%
2586
December11th to 20thNight
25%
795
9%
4724
8%
779
32%
779
8%
3394
December21st to endNight
18%
960
7%
6606
6%
929
25%
929
4%
5288

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
14%9%37%5%4445%7%36%
105345
Night
15%10%37%5%4435%7%37%
103643
TransparencyDay
45%6%12%22%14%1
109027
Night
45%6%11%22%14%2
108100
SeeingDay
18%11%26%23%16%6%
15542
Night
19%8%26%30%15%2
25309

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 10thDay
16%18%6%9%44445%5%26%
2575
11th to 20thDay
16%15%7%12%5%6%5%44422%
2746
21st to endDay
29%18%8%7%43233418%
3124
February1st to 10thDay
19%15%49%5%44345%29%
1805
11th to 20thDay
16%12%411%5%5%3346%31%
1848
21st to endDay
19%13%5%9%6%34245%31%
1570
March1st to 10thDay
22%16%5%9%44434426%
3144
11th to 20thDay
14%9%36%44445%7%41%
3480
21st to endDay
18%9%38%44445%7%34%
3815
April1st to 10thDay
14%11%37%5%4445%7%35%
2242
11th to 20thDay
16%9%27%45%435%7%39%
2308
21st to endDay
18%8%37%5%5%435%6%36%
2470
May1st to 10thDay
21%9%47%445%45%7%29%
4082
11th to 20thDay
20%8%36%43435%7%38%
4081
21st to endDay
10%6%38%6%5%6%5%8%10%34%
4476
June1st to 10thDay
12%6%26%5%5%5%5%7%8%40%
2478
11th to 20thDay
9%5%37%5%5%5%5%6%9%43%
2660
21st to endDay
9%6%36%5%46%5%6%10%40%
2660
July1st to 10thDay
11%7%37%5%5%5%47%9%37%
4440
11th to 20thDay
7%426%5%45%5%7%11%45%
4294
21st to endDay
11%7%37%6%6%7%5%7%10%32%
4466
August1st to 10thDay
8%5%26%45%6%48%10%43%
4104
11th to 20thDay
8%6%26%45%5%47%10%42%
4044
21st to endDay
6%425%43436%9%53%
4217
September1st to 10thDay
12%5%26%34446%7%48%
2163
11th to 20thDay
9%5%25%44446%9%49%
2090
21st to endDay
15%7%25%44335%6%46%
2090
October1st to 10thDay
10%5%26%5%5%435%6%49%
2090
11th to 20thDay
13%7%26%5%4335%6%46%
1929
21st to endDay
20%8%27%43335%6%38%
1943
November1st to 10thDay
9%7%36%344346%52%
1762
11th to 20thDay
15%11%49%44336%7%36%
1800
21st to endDay
18%11%47%5%4435%5%35%
1800
December1st to 10thDay
18%11%47%5%44245%37%
2930
11th to 20thDay
17%14%5%9%5%5%5%35%5%26%
3373
21st to endDay
21%20%5%10%5%44345%18%
4246
January1st to 10thNight
16%18%6%12%6%5%4345%20%
4513
11th to 20thNight
15%17%6%15%6%5%4345%21%
4210
21st to endNight
26%18%6%8%44333421%
4532
February1st to 10thNight
21%12%39%5%44445%29%
2371
11th to 20thNight
15%11%49%6%45%45%6%31%
2218
21st to endNight
21%13%48%344446%30%
1884
March1st to 10thNight
22%14%35%443345%33%
3707
11th to 20thNight
12%8%27%44445%6%44%
3480
21st to endNight
17%8%37%444446%39%
3817
April1st to 10thNight
14%9%36%5%45%5%5%7%38%
1952
11th to 20thNight
15%8%25%44346%7%40%
1820
21st to endNight
16%7%26%5%45%46%7%37%
1710
May1st to 10thNight
21%11%49%5%5%445%6%27%
2813
11th to 20thNight
18%7%26%44445%8%38%
2812
21st to endNight
9%5%26%44447%10%45%
3079
June1st to 10thNight
9%5%25%5%4435%9%48%
1696
11th to 20thNight
8%6%243445%7%11%46%
1520
21st to endNight
6%425%5%46%48%10%46%
1520
July1st to 10thNight
12%6%25%33445%7%49%
2530
11th to 20thNight
6%415%44447%9%52%
2654
21st to endNight
10%7%37%5%5%5%5%7%10%37%
3087
August1st to 10thNight
8%7%27%5%45%46%8%44%
2825
11th to 20thNight
7%6%27%45%5%45%7%46%
2785
21st to endNight
4224345%46%10%57%
3435
September1st to 10thNight
12%5%1443435%6%51%
1996
11th to 20thNight
7%5%25%34435%7%56%
2090
21st to endNight
13%7%26%434346%49%
2090
October1st to 10thNight
8%426%44335%6%55%
2090
11th to 20thNight
14%7%26%5%4435%7%44%
2251
21st to endNight
17%9%26%445%345%41%
2651
November1st to 10thNight
13%8%2443435%6%47%
2536
11th to 20thNight
16%9%27%44435%6%40%
2600
21st to endNight
19%13%47%5%44347%30%
2600
December1st to 10thNight
17%11%48%443345%38%
4250
11th to 20thNight
19%14%6%10%5%4335%5%25%
4822
21st to endNight
22%18%6%11%6%5%4345%16%
6697

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
60%5%11%15%9%
2576
11th to 20thDay
64%5%12%13%5%
2746
21st to endDay
71%39%13%31
3124
February1st to 10thDay
57%5%10%16%9%1
1805
11th to 20thDay
56%410%20%9%1
1858
21st to endDay
56%5%9%19%8%2
1570
March1st to 10thDay
60%6%7%18%8%1
3144
11th to 20thDay
41%6%11%24%16%1
3480
21st to endDay
47%7%12%22%11%1
3815
April1st to 10thDay
47%7%11%22%12%1
2242
11th to 20thDay
45%5%11%22%14%3
2308
21st to endDay
48%6%10%22%11%2
2470
May1st to 10thDay
52%9%12%20%7%1
4120
11th to 20thDay
46%8%13%22%12%
4085
21st to endDay
39%12%14%19%15%2
4489
June1st to 10thDay
40%9%11%22%16%2
2478
11th to 20thDay
35%9%14%23%18%2
2660
21st to endDay
38%9%15%20%14%4
2660
July1st to 10thDay
43%5%12%20%18%2
4371
11th to 20thDay
32%6%11%31%19%1
4219
21st to endDay
45%7%14%17%13%3
4324
August1st to 10thDay
33%7%17%30%12%1
4091
11th to 20thDay
35%5%12%32%16%1
4083
21st to endDay
28%5%14%30%20%3
4216
September1st to 10thDay
34%6%11%23%20%6%
2163
11th to 20thDay
31%7%12%25%22%3
2090
21st to endDay
39%5%10%23%21%2
2090
October1st to 10thDay
24%49%32%30%2
3480
11th to 20thDay
31%39%30%26%1
3182
21st to endDay
37%310%25%23%2
3180
November1st to 10thDay
34%5%10%29%20%2
1762
11th to 20thDay
48%410%21%15%3
1800
21st to endDay
52%410%21%12%1
1800
December1st to 10thDay
51%39%26%10%
2930
11th to 20thDay
61%5%9%18%7%
3370
21st to endDay
68%410%12%5%
4246
January1st to 10thNight
64%7%9%14%7%
4513
11th to 20thNight
66%5%10%14%6%
4210
21st to endNight
67%49%15%5%1
4532
February1st to 10thNight
58%5%10%19%7%1
2371
11th to 20thNight
53%5%10%20%11%1
2219
21st to endNight
57%411%16%9%2
1884
March1st to 10thNight
52%5%8%23%10%1
3707
11th to 20thNight
38%7%13%25%15%1
3480
21st to endNight
45%6%10%27%11%1
3817
April1st to 10thNight
44%6%12%24%12%2
1952
11th to 20thNight
40%6%11%18%19%5%
1820
21st to endNight
45%6%12%20%13%3
1710
May1st to 10thNight
56%9%8%18%7%2
2840
11th to 20thNight
42%8%14%25%9%1
2813
21st to endNight
29%10%18%24%13%5%
3087
June1st to 10thNight
32%8%11%26%21%2
1696
11th to 20thNight
30%8%15%22%20%4
1520
21st to endNight
30%8%17%22%17%5%
1520
July1st to 10thNight
35%6%11%25%18%6%
2490
11th to 20thNight
27%7%13%32%20%2
2606
21st to endNight
40%6%13%23%14%4
2988
August1st to 10thNight
36%6%14%30%12%1
2814
11th to 20thNight
35%6%12%28%18%1
2812
21st to endNight
22%5%16%31%22%3
3435
September1st to 10thNight
32%6%12%24%19%7%
1996
11th to 20thNight
28%6%10%25%27%3
2090
21st to endNight
37%5%9%21%25%2
2090
October1st to 10thNight
23%37%28%36%3
3480
11th to 20thNight
28%410%26%32%2
3737
21st to endNight
34%48%23%27%5%
4364
November1st to 10thNight
38%5%12%21%22%3
2536
11th to 20thNight
45%5%9%22%17%3
2600
21st to endNight
54%5%10%21%10%1
2600
December1st to 10thNight
50%412%25%10%
4250
11th to 20thNight
60%411%18%7%
4824
21st to endNight
70%49%13%3
6697

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
25%21%33%15%6%
288
11th to 20thDay
29%23%34%11%3
270
21st to endDay
33%20%29%15%3
297
February1st to 10thDay
26%23%31%17%3
270
11th to 20thDay
28%24%31%14%2
270
21st to endDay
29%18%42%8%2
225
March1st to 10thDay
25%25%34%13%2
281
11th to 20thDay
27%15%33%19%6%
460
21st to endDay
29%17%31%16%7%
506
April1st to 10thDay
21%19%29%20%9%1
460
11th to 20thDay
21%20%24%21%11%4
452
21st to endDay
22%16%33%17%9%2
460
May1st to 10thDay
23%14%31%19%9%4
463
11th to 20thDay
22%9%27%22%14%6%
487
21st to endDay
13%7%23%29%17%11%
529
June1st to 10thDay
14%7%22%29%19%9%
498
11th to 20thDay
11%6%23%32%23%6%
680
21st to endDay
10%7%24%32%18%8%
680
July1st to 10thDay
13%417%26%24%17%
671
11th to 20thDay
9%424%26%25%12%
587
21st to endDay
13%218%28%26%13%
532
August1st to 10thDay
9%417%26%26%18%
486
11th to 20thDay
12%420%29%23%13%
479
21st to endDay
11%313%27%31%15%
539
September1st to 10thDay
11%417%25%32%11%
490
11th to 20thDay
10%314%27%33%13%
490
21st to endDay
17%8%22%24%20%9%
490
October1st to 10thDay
10%7%23%31%22%7%
490
11th to 20thDay
15%14%30%23%14%4
490
21st to endDay
23%13%33%24%7%1
392
November1st to 10thDay
11%13%38%23%11%3
300
11th to 20thDay
23%18%29%20%8%2
300
21st to endDay
25%14%39%18%4
300
December1st to 10thDay
20%20%36%16%6%1
300
11th to 20thDay
22%20%39%13%6%
300
21st to endDay
32%16%32%16%31
330
January1st to 10thNight
23%17%30%24%5%
981
11th to 20thNight
28%14%33%22%3
811
21st to endNight
25%14%32%27%3
836
February1st to 10thNight
30%10%30%29%2
760
11th to 20thNight
22%15%35%24%3
743
21st to endNight
28%13%31%25%2
628
March1st to 10thNight
22%11%35%26%5%
760
11th to 20thNight
22%13%33%25%6%1
760
21st to endNight
22%12%30%28%7%
836
April1st to 10thNight
18%12%36%26%8%
622
11th to 20thNight
19%9%31%29%10%1
563
21st to endNight
18%8%37%28%9%1
570
May1st to 10thNight
23%8%28%27%12%1
570
11th to 20thNight
18%425%34%18%2
561
21st to endNight
10%223%34%27%3
617
June1st to 10thNight
10%319%42%24%1
570
11th to 20thNight
11%218%44%23%4
570
21st to endNight
6%221%43%26%2
570
July1st to 10thNight
13%113%35%31%7%
555
11th to 20thNight
7%215%39%33%4
552
21st to endNight
10%312%41%31%3
624
August1st to 10thNight
9%214%35%37%4
567
11th to 20thNight
8%114%42%30%4
564
21st to endNight
6%113%33%41%6%
627
September1st to 10thNight
14%214%32%33%4
666
11th to 20thNight
10%313%34%35%5%
760
21st to endNight
16%5%21%29%26%2
760
October1st to 10thNight
11%422%35%23%4
760
11th to 20thNight
18%8%27%30%15%1
760
21st to endNight
22%8%31%27%12%
836
November1st to 10thNight
18%8%28%29%16%1
780
11th to 20thNight
22%12%29%27%10%1
800
21st to endNight
25%10%26%31%7%1
800
December1st to 10thNight
27%11%31%25%6%
800
11th to 20thNight
24%10%33%27%6%1
800
21st to endNight
30%15%28%23%3
970
Page generated at 2025-01-04 03:24:00. Version ac07

Copyright © 2025 Attilla Danko.


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