Linslaw Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Linslaw Point clear sky chart from 2005-11-06 to 2024-03-06.

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
44%
22979
13%
80703
13%
22875
47%
22875
16%
58205

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
22%
753
3%
4405
5%
736
25%
736
3%
3931
January11th to 20thNight
29%
760
7%
4301
7%
740
32%
740
5%
3637
January21st to endNight
34%
835
7%
4497
11%
814
37%
814
6%
3795
February1st to 10thNight
35%
760
7%
2470
7%
760
35%
760
9%
2019
February11th to 20thNight
35%
740
9%
2404
7%
740
38%
740
12%
1891
February21st to endNight
30%
628
10%
1989
8%
628
34%
628
9%
1621
March1st to 10thNight
31%
742
8%
2063
7%
742
33%
742
13%
1676
March11th to 20thNight
34%
720
10%
1980
8%
720
36%
720
14%
1583
March21st to endNight
29%
792
5%
2178
4%
792
30%
792
11%
1819
April1st to 10thNight
31%
720
8%
1800
5%
720
32%
720
13%
1492
April11th to 20thNight
36%
694
12%
1762
6%
694
38%
694
18%
1343
April21st to endNight
41%
540
12%
1620
8%
540
44%
540
16%
1192
May1st to 10thNight
44%
500
13%
1580
10%
500
47%
500
22%
1049
May11th to 20thNight
49%
354
12%
1416
13%
354
52%
354
16%
947
May21st to endNight
49%
389
11%
1552
13%
388
53%
388
18%
1001
June1st to 10thNight
54%
360
10%
1440
16%
360
56%
360
19%
912
June11th to 20thNight
57%
360
13%
1440
17%
360
62%
360
25%
816
June21st to endNight
66%
360
17%
1440
25%
360
72%
360
37%
671
July1st to 10thNight
74%
350
20%
1400
30%
350
79%
350
48%
573
July11th to 20thNight
72%
348
27%
1392
37%
348
78%
348
46%
580
July21st to endNight
83%
498
32%
1587
36%
471
87%
471
69%
597
August1st to 10thNight
80%
537
26%
1602
23%
534
83%
534
54%
744
August11th to 20thNight
79%
534
32%
1602
27%
534
80%
534
55%
740
August21st to endNight
68%
702
32%
1890
21%
702
71%
702
53%
972
September1st to 10thNight
68%
720
31%
1800
18%
720
70%
720
55%
970
September11th to 20thNight
64%
720
26%
1854
18%
720
66%
720
40%
1132
September21st to endNight
60%
720
23%
2031
21%
720
62%
720
34%
1233
October1st to 10thNight
52%
720
16%
2160
14%
720
56%
720
29%
1354
October11th to 20thNight
56%
720
20%
2160
21%
720
58%
720
25%
1432
October21st to endNight
38%
792
17%
2376
14%
792
44%
792
19%
1713
November1st to 10thNight
40%
740
11%
2464
12%
740
41%
740
12%
1891
November11th to 20thNight
30%
760
8%
2660
8%
760
32%
760
10%
2123
November21st to endNight
38%
760
8%
2660
8%
760
41%
760
13%
1968
December1st to 10thNight
38%
760
11%
2660
10%
760
41%
760
13%
1993
December11th to 20thNight
29%
759
6%
3235
6%
759
31%
759
7%
2669
December21st to endNight
23%
832
3%
4833
5%
817
25%
817
3%
4126

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
21%9%36%5%34446%33%
78543
Night
23%10%36%5%34445%32%
80999
TransparencyDay
52%7%11%16%11%3
78253
Night
52%7%12%16%10%3
80811
SeeingDay
25%13%24%25%11%2
13862
Night
27%7%15%29%20%2
22996

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
35%18%6%8%6%344339%
2539
11th to 20thDay
39%13%46%5%3443415%
2645
21st to endDay
35%13%48%6%45%445%13%
3146
February1st to 10thDay
29%15%49%7%45%45%6%14%
1710
11th to 20thDay
28%14%49%6%345%45%18%
1665
21st to endDay
31%17%5%8%6%2434417%
1465
March1st to 10thDay
30%13%5%8%7%45%45%5%14%
2008
11th to 20thDay
32%11%47%6%3435%6%18%
1980
21st to endDay
33%13%5%10%7%4443413%
2178
April1st to 10thDay
31%13%5%10%8%4444415%
2160
11th to 20thDay
27%13%5%8%6%34435%21%
2141
21st to endDay
23%10%5%7%6%4445%7%25%
2340
May1st to 10thDay
17%9%47%6%36%448%32%
2380
11th to 20thDay
20%11%47%6%3446%8%27%
2477
21st to endDay
24%8%46%6%35%5%5%7%27%
2723
June1st to 10thDay
23%8%37%5%245%5%6%31%
2520
11th to 20thDay
16%8%36%6%35%5%5%9%32%
2520
21st to endDay
11%5%24423348%53%
2520
July1st to 10thDay
5%424424446%61%
2520
11th to 20thDay
8%413313346%64%
2520
21st to endDay
4212322336%72%
2634
August1st to 10thDay
331442445%8%62%
2328
11th to 20thDay
5%213323447%65%
2298
21st to endDay
5%5%2332346%8%59%
2466
September1st to 10thDay
6%313323346%66%
2160
11th to 20thDay
10%6%46%5%245%5%7%47%
2102
21st to endDay
15%6%26%5%2345%6%45%
1928
October1st to 10thDay
17%9%35%5%3445%5%41%
1800
11th to 20thDay
19%6%37%6%35%5%5%8%33%
1800
21st to endDay
23%10%37%6%34446%29%
1980
November1st to 10thDay
31%10%5%7%6%445%45%18%
1608
11th to 20thDay
33%9%48%6%35%446%18%
1520
21st to endDay
29%10%37%7%45%45%5%22%
1520
December1st to 10thDay
26%11%48%7%335%46%24%
1520
11th to 20thDay
29%12%48%7%35%5%7%6%13%
1928
21st to endDay
34%16%49%6%35%5%45%9%
2794
January1st to 10thNight
35%18%5%8%9%443339%
4406
11th to 20thNight
39%14%47%5%2433416%
4314
21st to endNight
41%15%46%42323415%
4521
February1st to 10thNight
26%13%5%8%6%45%5%5%5%18%
2470
11th to 20thNight
26%12%47%5%3445%426%
2402
21st to endNight
28%14%48%5%4445%5%20%
1989
March1st to 10thNight
27%13%5%7%6%3445%5%22%
2063
11th to 20thNight
26%12%47%6%35%445%24%
1980
21st to endNight
31%13%48%6%34345%20%
2178
April1st to 10thNight
27%16%5%7%5%44345%22%
1800
11th to 20thNight
22%12%37%5%3445%6%30%
1762
21st to endNight
20%10%46%6%35%45%7%30%
1620
May1st to 10thNight
14%9%36%6%2445%6%40%
1580
11th to 20thNight
16%10%46%6%445%5%7%33%
1416
21st to endNight
16%6%45%5%25%5%6%7%38%
1552
June1st to 10thNight
17%8%35%4345%5%7%40%
1440
11th to 20thNight
12%6%3432445%9%47%
1440
21st to endNight
9%313334446%59%
1440
July1st to 10thNight
3414322336%69%
1440
11th to 20thNight
5%313324445%66%
1440
21st to endNight
2212211237%76%
1680
August1st to 10thNight
22123235%5%8%65%
1611
11th to 20thNight
3213333446%69%
1602
21st to endNight
4323423347%65%
1890
September1st to 10thNight
6%413323345%66%
1800
11th to 20thNight
8%6%25%43345%7%53%
1854
21st to endNight
12%6%25%42345%6%51%
2031
October1st to 10thNight
14%6%26%433346%49%
2160
11th to 20thNight
18%7%35%5%3345%6%42%
2160
21st to endNight
23%10%36%434445%34%
2376
November1st to 10thNight
29%9%45%6%35%45%5%25%
2464
11th to 20thNight
31%9%37%7%4445%5%21%
2660
21st to endNight
24%9%36%5%35%5%5%6%28%
2660
December1st to 10thNight
26%11%36%5%35%45%6%26%
2660
11th to 20thNight
30%12%5%8%6%35%45%6%17%
3276
21st to endNight
28%14%5%9%7%445%5%5%14%
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
78%7%8%421
2539
11th to 20thDay
73%6%7%6%43
2645
21st to endDay
73%7%8%7%5%1
3146
February1st to 10thDay
70%7%9%9%5%1
1710
11th to 20thDay
68%8%10%8%42
1674
21st to endDay
71%6%8%8%5%2
1465
March1st to 10thDay
71%8%8%10%3
2008
11th to 20thDay
65%6%11%13%5%1
1980
21st to endDay
74%7%7%9%1
2178
April1st to 10thDay
72%6%10%8%5%
2160
11th to 20thDay
65%6%10%10%5%2
2144
21st to endDay
59%8%13%13%7%1
2340
May1st to 10thDay
49%8%16%18%9%
2380
11th to 20thDay
54%7%15%17%7%1
2480
21st to endDay
54%9%16%17%3
2724
June1st to 10thDay
53%7%14%22%4
2520
11th to 20thDay
47%9%19%19%5%
2520
21st to endDay
30%6%18%29%14%3
2520
July1st to 10thDay
22%6%17%25%24%6%
2451
11th to 20thDay
22%5%8%25%30%11%
2445
21st to endDay
14%310%28%36%9%
2488
August1st to 10thDay
19%7%17%31%20%6%
2312
11th to 20thDay
18%5%14%33%24%6%
2298
21st to endDay
22%6%13%29%26%5%
2466
September1st to 10thDay
19%5%10%29%24%13%
2160
11th to 20thDay
36%6%12%22%17%6%
2102
21st to endDay
39%7%12%20%17%5%
1928
October1st to 10thDay
44%8%10%15%18%5%
1800
11th to 20thDay
48%8%11%14%16%3
1800
21st to endDay
55%7%9%12%14%3
1980
November1st to 10thDay
66%7%9%12%5%
1608
11th to 20thDay
66%7%9%8%7%3
1520
21st to endDay
62%7%8%7%12%4
1520
December1st to 10thDay
61%7%10%11%11%1
1520
11th to 20thDay
68%11%9%8%3
1928
21st to endDay
75%8%8%6%21
2794
January1st to 10thNight
80%6%6%431
4406
11th to 20thNight
73%7%6%8%42
4314
21st to endNight
74%47%8%6%1
4521
February1st to 10thNight
66%8%11%11%41
2470
11th to 20thNight
61%7%12%12%7%2
2404
21st to endNight
64%9%9%11%6%2
1989
March1st to 10thNight
63%7%11%13%6%1
2063
11th to 20thNight
61%7%12%14%6%1
1980
21st to endNight
67%7%13%11%2
2178
April1st to 10thNight
65%7%11%13%5%1
1800
11th to 20thNight
54%8%15%15%44
1762
21st to endNight
53%8%13%18%7%2
1620
May1st to 10thNight
44%7%17%23%8%2
1580
11th to 20thNight
48%8%17%19%6%3
1416
21st to endNight
42%10%21%22%4
1552
June1st to 10thNight
43%8%17%29%3
1440
11th to 20thNight
32%10%24%26%8%1
1440
21st to endNight
23%6%21%33%13%4
1440
July1st to 10thNight
17%419%30%24%8%
1400
11th to 20thNight
17%5%12%24%31%11%
1392
21st to endNight
10%211%32%36%10%
1587
August1st to 10thNight
13%8%19%36%18%6%
1602
11th to 20thNight
15%6%13%34%26%7%
1602
21st to endNight
17%6%13%33%23%7%
1890
September1st to 10thNight
18%5%12%27%25%13%
1800
11th to 20thNight
30%6%14%25%16%8%
1854
21st to endNight
32%7%14%21%17%9%
2031
October1st to 10thNight
37%7%12%22%16%7%
2160
11th to 20thNight
42%7%13%18%16%4
2160
21st to endNight
51%6%10%13%14%5%
2376
November1st to 10thNight
59%8%11%12%10%1
2464
11th to 20thNight
64%7%10%10%6%3
2660
21st to endNight
56%8%11%9%11%5%
2660
December1st to 10thNight
59%5%11%14%10%1
2660
11th to 20thNight
68%8%11%9%5%
3276
21st to endNight
68%13%8%7%21
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
49%17%18%9%7%
180
11th to 20thDay
44%12%18%16%9%1
246
21st to endDay
37%12%19%20%11%1
407
February1st to 10thDay
40%11%20%21%7%1
370
11th to 20thDay
40%16%18%21%5%1
365
21st to endDay
42%17%18%18%5%
332
March1st to 10thDay
40%17%21%16%5%1
441
11th to 20thDay
34%15%21%20%7%1
420
21st to endDay
40%16%20%17%6%
462
April1st to 10thDay
42%16%16%18%7%1
420
11th to 20thDay
38%19%20%15%6%3
412
21st to endDay
30%17%26%19%7%2
420
May1st to 10thDay
21%18%29%20%9%3
423
11th to 20thDay
33%14%23%19%9%3
448
21st to endDay
23%15%25%22%13%2
485
June1st to 10thDay
24%13%26%24%11%2
450
11th to 20thDay
20%21%28%23%8%1
450
21st to endDay
11%9%28%35%15%2
450
July1st to 10thDay
7%8%33%34%16%3
446
11th to 20thDay
6%9%33%34%16%2
444
21st to endDay
26%28%43%17%4
487
August1st to 10thDay
38%28%38%18%5%
447
11th to 20thDay
45%22%41%23%5%
437
21st to endDay
7%9%31%33%18%3
495
September1st to 10thDay
8%9%30%31%19%3
450
11th to 20thDay
16%8%26%29%18%4
450
21st to endDay
20%12%26%29%9%4
450
October1st to 10thDay
23%11%25%23%15%4
450
11th to 20thDay
24%11%19%25%18%4
450
21st to endDay
31%13%22%22%8%4
495
November1st to 10thDay
37%14%20%21%8%1
262
11th to 20thDay
35%11%29%16%7%2
180
21st to endDay
34%14%18%28%6%
180
December1st to 10thDay
37%11%23%19%9%1
180
11th to 20thDay
43%11%28%14%31
180
21st to endDay
41%14%21%19%5%
198
January1st to 10thNight
47%9%15%18%9%2
760
11th to 20thNight
40%8%14%22%14%2
760
21st to endNight
36%6%14%28%13%2
836
February1st to 10thNight
35%9%13%28%14%2
760
11th to 20thNight
35%7%16%29%12%1
744
21st to endNight
38%11%13%25%13%
628
March1st to 10thNight
36%11%16%26%11%1
742
11th to 20thNight
33%9%14%29%14%1
720
21st to endNight
39%9%15%22%14%1
792
April1st to 10thNight
39%9%14%22%15%1
720
11th to 20thNight
27%11%20%25%15%2
694
21st to endNight
26%7%16%30%19%1
540
May1st to 10thNight
20%8%21%27%21%2
500
11th to 20thNight
23%6%15%30%25%2
354
21st to endNight
19%6%20%31%23%2
389
June1st to 10thNight
20%415%38%22%2
360
11th to 20thNight
14%5%18%44%16%3
360
21st to endNight
11%315%41%30%1
360
July1st to 10thNight
6%211%43%37%1
350
11th to 20thNight
7%215%49%26%
348
21st to endNight
3210%43%39%3
498
August1st to 10thNight
429%39%40%7%
537
11th to 20thNight
5%18%35%45%6%
534
21st to endNight
8%416%39%30%3
702
September1st to 10thNight
8%416%37%33%2
720
11th to 20thNight
12%414%29%34%7%
720
21st to endNight
16%5%14%34%28%3
720
October1st to 10thNight
19%5%18%31%25%3
720
11th to 20thNight
23%5%11%31%25%5%
720
21st to endNight
30%9%16%23%17%4
792
November1st to 10thNight
35%6%14%28%16%1
740
11th to 20thNight
36%11%15%24%12%1
760
21st to endNight
28%9%17%30%14%2
760
December1st to 10thNight
32%8%17%26%16%2
760
11th to 20thNight
41%8%16%21%14%1
760
21st to endNight
45%10%14%23%7%
836
Page generated at 2024-03-03 03:28:59. Version ac07

Copyright © 2024 Attilla Danko.


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