Gualala
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gualala clear sky chart from 2005-11-06 to 2024-03-08.

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
55%
23776
16%
80498
13%
23679
59%
23679
16%
57842

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
43%
752
10%
4116
7%
736
46%
736
7%
2795
January11th to 20thNight
46%
753
12%
4095
12%
740
51%
740
7%
3228
January21st to endNight
49%
833
10%
4462
16%
814
53%
814
7%
3602
February1st to 10thNight
46%
760
17%
2470
14%
760
53%
760
16%
1758
February11th to 20thNight
42%
740
13%
2404
11%
740
47%
740
12%
1808
February21st to endNight
43%
628
15%
1854
10%
628
49%
628
15%
1388
March1st to 10thNight
37%
750
12%
2061
7%
750
42%
750
12%
1659
March11th to 20thNight
43%
720
13%
1980
10%
720
47%
720
13%
1569
March21st to endNight
38%
792
12%
2178
6%
792
44%
792
14%
1679
April1st to 10thNight
37%
720
15%
1828
5%
720
43%
720
15%
1395
April11th to 20thNight
40%
711
18%
1779
6%
711
46%
711
17%
1338
April21st to endNight
42%
682
19%
1762
4%
682
50%
682
23%
1233
May1st to 10thNight
48%
540
21%
1620
9%
540
57%
540
21%
1074
May11th to 20thNight
55%
531
20%
1594
11%
531
62%
531
21%
1084
May21st to endNight
51%
402
18%
1565
11%
401
63%
401
14%
1018
June1st to 10thNight
47%
360
14%
1440
8%
360
59%
360
13%
991
June11th to 20thNight
56%
360
23%
1440
18%
360
71%
360
18%
871
June21st to endNight
68%
360
23%
1440
26%
360
76%
360
21%
861
July1st to 10thNight
68%
396
19%
1446
17%
396
75%
396
24%
870
July11th to 20thNight
76%
522
21%
1566
19%
522
78%
522
28%
983
July21st to endNight
78%
591
21%
1674
17%
558
79%
558
22%
1137
August1st to 10thNight
76%
537
21%
1602
16%
534
79%
534
27%
1019
August11th to 20thNight
77%
544
25%
1612
17%
544
80%
544
26%
1035
August21st to endNight
77%
792
26%
1980
17%
792
79%
792
33%
1306
September1st to 10thNight
77%
720
28%
1800
18%
720
79%
720
35%
1174
September11th to 20thNight
69%
720
24%
1869
17%
720
72%
720
25%
1302
September21st to endNight
69%
720
24%
2026
21%
720
73%
720
27%
1340
October1st to 10thNight
66%
720
17%
2160
16%
720
71%
720
21%
1473
October11th to 20thNight
68%
720
22%
2160
21%
720
73%
720
21%
1486
October21st to endNight
65%
792
23%
2376
22%
792
70%
792
21%
1643
November1st to 10thNight
55%
740
13%
2220
9%
740
60%
740
14%
1702
November11th to 20thNight
56%
760
13%
2532
12%
760
60%
760
14%
1868
November21st to endNight
54%
760
14%
2660
14%
760
57%
760
15%
1852
December1st to 10thNight
49%
760
15%
2660
13%
760
53%
760
14%
1956
December11th to 20thNight
45%
760
11%
3254
11%
759
48%
759
8%
2661
December21st to endNight
37%
828
6%
4813
6%
817
40%
817
4%
3684

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
12%42432335%8%54%
78712
Night
14%5%24423447%51%
80883
TransparencyDay
22%35%8%14%13%8%
78436
Night
25%35%7%13%13%8%
80682
SeeingDay
14%10%24%27%19%6%
14455
Night
15%6%17%28%26%8%
23806

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
21%8%36%5%2446%6%37%
2795
11th to 20thDay
30%8%37%5%33346%28%
2860
21st to endDay
27%9%35%43445%7%30%
3146
February1st to 10thDay
21%6%35%434345%42%
1710
11th to 20thDay
18%6%2442446%9%40%
1665
21st to endDay
20%5%245%3445%6%44%
1594
March1st to 10thDay
22%8%35%5%2445%7%33%
2059
11th to 20thDay
20%7%34436%448%37%
1980
21st to endDay
17%6%244345%6%8%42%
2178
April1st to 10thDay
18%6%245%245%6%8%40%
2132
11th to 20thDay
11%4245%35%46%9%48%
2129
21st to endDay
8%31243446%10%54%
2195
May1st to 10thDay
7%414323448%60%
2340
11th to 20thDay
8%31222445%9%59%
2300
21st to endDay
7%31332436%9%58%
2706
June1st to 10thDay
7%5%2332436%10%56%
2520
11th to 20thDay
3113313337%73%
2520
21st to endDay
3112212336%77%
2520
July1st to 10thDay
1212213337%75%
2466
11th to 20thDay
1213323227%75%
2340
21st to endDay
1213334348%70%
2546
August1st to 10thDay
1213233246%72%
2328
11th to 20thDay
1113223248%73%
2285
21st to endDay
2424322348%68%
2376
September1st to 10thDay
1112212337%78%
2160
11th to 20thDay
4313322349%64%
2088
21st to endDay
5%212222336%72%
1933
October1st to 10thDay
7%323212235%69%
1800
11th to 20thDay
11%313325%248%57%
1800
21st to endDay
12%32332335%9%55%
1980
November1st to 10thDay
12%5%23425%449%49%
1859
11th to 20thDay
15%6%2442445%8%47%
1640
21st to endDay
12%3234345%5%9%50%
1520
December1st to 10thDay
21%6%2432445%7%41%
1520
11th to 20thDay
34%8%35%42345%5%27%
1928
21st to endDay
27%8%35%42445%8%31%
2794
January1st to 10thNight
20%8%244345%6%8%36%
4155
11th to 20thNight
25%10%36%6%44446%29%
4110
21st to endNight
30%10%36%5%33446%27%
4521
February1st to 10thNight
19%5%244235%5%7%44%
2470
11th to 20thNight
17%7%344345%7%8%39%
2402
21st to endNight
17%7%1332445%6%48%
1854
March1st to 10thNight
23%9%36%435%5%5%5%33%
2061
11th to 20thNight
21%6%25%43445%6%39%
1980
21st to endNight
18%6%24324446%47%
2178
April1st to 10thNight
14%7%35%43445%7%44%
1828
11th to 20thNight
11%43443445%6%52%
1779
21st to endNight
7%31332435%8%60%
1762
May1st to 10thNight
6%5%2332335%8%61%
1620
11th to 20thNight
44344233411%59%
1593
21st to endNight
5%42432345%9%60%
1565
June1st to 10thNight
6%7%2342435%9%55%
1440
11th to 20thNight
3211222337%74%
1440
21st to endNight
33222223476%
1440
July1st to 10thNight
221331223478%
1488
11th to 20thNight
121232223477%
1620
21st to endNight
1313322248%70%
1773
August1st to 10thNight
1312212346%74%
1611
11th to 20thNight
1323222247%72%
1612
21st to endNight
1323222225%75%
1980
September1st to 10thNight
1112211337%78%
1800
11th to 20thNight
5%424222347%66%
1869
21st to endNight
4322322435%70%
2026
October1st to 10thNight
5%42332223469%
2160
11th to 20thNight
7%423323347%61%
2160
21st to endNight
12%313323446%60%
2376
November1st to 10thNight
13%4234245%6%8%49%
2220
11th to 20thNight
17%4244345%6%8%44%
2532
21st to endNight
13%42442345%7%52%
2660
December1st to 10thNight
23%7%24423347%42%
2660
11th to 20thNight
34%6%14324447%30%
3276
21st to endNight
26%8%35%423347%34%
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
33%28%14%18%5%2
2795
11th to 20thDay
44%28%8%9%6%5%
2860
21st to endDay
44%25%8%14%6%3
3146
February1st to 10thDay
26%35%6%14%13%6%
1710
11th to 20thDay
26%37%8%14%11%3
1674
21st to endDay
26%37%9%15%10%3
1594
March1st to 10thDay
31%38%9%12%9%2
2059
11th to 20thDay
30%38%10%12%7%2
1980
21st to endDay
26%38%8%14%12%2
2178
April1st to 10thDay
25%39%10%15%8%3
2132
11th to 20thDay
21%37%10%16%12%4
2132
21st to endDay
15%38%11%19%12%4
2195
May1st to 10thDay
14%36%8%18%17%5%
2340
11th to 20thDay
13%36%9%22%15%6%
2303
21st to endDay
16%39%11%21%14%1
2707
June1st to 10thDay
19%38%10%16%14%2
2520
11th to 20thDay
10%37%7%14%23%9%
2520
21st to endDay
11%36%7%14%19%13%
2520
July1st to 10thDay
10%35%412%19%20%
2400
11th to 20thDay
13%36%6%10%13%23%
2271
21st to endDay
17%36%7%9%13%18%
2405
August1st to 10thDay
12%35%7%15%18%13%
2312
11th to 20thDay
13%33%7%11%20%15%
2285
21st to endDay
14%34%8%11%17%16%
2376
September1st to 10thDay
11%35%6%12%15%21%
2160
11th to 20thDay
18%35%7%17%17%6%
2088
21st to endDay
11%35%7%17%18%12%
1933
October1st to 10thDay
16%36%6%16%17%8%
1800
11th to 20thDay
18%36%9%13%15%9%
1800
21st to endDay
19%37%7%15%12%9%
1980
November1st to 10thDay
24%42%6%16%8%4
1859
11th to 20thDay
24%41%8%13%9%5%
1640
21st to endDay
18%41%11%10%13%7%
1520
December1st to 10thDay
23%42%7%10%12%5%
1520
11th to 20thDay
45%32%5%10%6%2
1928
21st to endDay
44%27%9%14%5%1
2794
January1st to 10thNight
33%29%18%13%6%1
4155
11th to 20thNight
44%28%7%11%6%5%
4110
21st to endNight
49%24%6%9%8%4
4521
February1st to 10thNight
23%35%7%15%13%7%
2470
11th to 20thNight
28%36%7%14%12%3
2404
21st to endNight
26%36%9%16%12%2
1854
March1st to 10thNight
31%38%6%10%12%2
2061
11th to 20thNight
31%37%8%14%8%3
1980
21st to endNight
26%38%10%15%9%2
2178
April1st to 10thNight
24%37%10%16%10%3
1828
11th to 20thNight
23%37%8%16%12%4
1779
21st to endNight
15%36%7%22%14%5%
1762
May1st to 10thNight
13%37%6%16%23%5%
1620
11th to 20thNight
15%37%7%18%17%6%
1594
21st to endNight
15%38%9%22%15%1
1565
June1st to 10thNight
19%39%7%15%17%3
1440
11th to 20thNight
11%36%6%13%23%11%
1440
21st to endNight
12%35%5%11%20%17%
1440
July1st to 10thNight
11%34%27%16%29%
1446
11th to 20thNight
9%36%48%13%30%
1566
21st to endNight
17%36%39%12%23%
1674
August1st to 10thNight
12%34%411%19%19%
1602
11th to 20thNight
13%35%48%16%24%
1612
21st to endNight
9%34%28%20%26%
1980
September1st to 10thNight
7%35%210%18%28%
1800
11th to 20thNight
16%35%6%14%20%9%
1869
21st to endNight
13%35%314%19%17%
2026
October1st to 10thNight
17%36%5%15%14%13%
2160
11th to 20thNight
17%36%412%19%12%
2160
21st to endNight
17%37%5%16%16%10%
2376
November1st to 10thNight
23%42%7%14%9%5%
2220
11th to 20thNight
22%41%9%12%11%5%
2532
21st to endNight
18%40%7%12%14%8%
2660
December1st to 10thNight
24%39%414%13%6%
2660
11th to 20thNight
41%33%7%10%8%1
3276
21st to endNight
44%28%9%13%5%1
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
32%16%22%14%13%3
332
11th to 20thDay
31%10%21%20%15%4
370
21st to endDay
25%10%19%28%15%3
407
February1st to 10thDay
24%12%22%20%18%5%
370
11th to 20thDay
27%14%24%20%14%2
365
21st to endDay
21%14%27%23%11%4
373
March1st to 10thDay
31%14%26%19%9%1
449
11th to 20thDay
29%11%28%19%10%3
420
21st to endDay
21%17%32%21%6%3
462
April1st to 10thDay
24%15%29%20%9%2
420
11th to 20thDay
17%17%33%20%9%4
412
21st to endDay
13%18%33%19%12%5%
420
May1st to 10thDay
10%14%33%26%13%4
423
11th to 20thDay
16%14%28%26%12%3
448
21st to endDay
12%13%27%29%14%5%
485
June1st to 10thDay
10%11%31%29%15%4
450
11th to 20thDay
6%13%34%29%16%2
450
21st to endDay
1428%37%24%5%
450
July1st to 10thDay
36%26%41%19%5%
446
11th to 20thDay
225%40%27%7%
444
21st to endDay
1217%43%30%8%
487
August1st to 10thDay
2326%38%24%6%
447
11th to 20thDay
2321%35%31%9%
437
21st to endDay
2419%36%31%9%
495
September1st to 10thDay
3420%34%30%9%
450
11th to 20thDay
5%7%21%33%25%8%
450
21st to endDay
6%7%23%27%29%8%
450
October1st to 10thDay
8%8%23%23%27%11%
450
11th to 20thDay
11%6%17%23%28%14%
450
21st to endDay
13%5%20%28%26%8%
495
November1st to 10thDay
16%9%19%25%23%8%
455
11th to 20thDay
16%8%15%24%26%11%
255
21st to endDay
16%422%23%23%12%
180
December1st to 10thDay
24%10%20%19%16%11%
180
11th to 20thDay
30%8%17%21%13%11%
180
21st to endDay
28%9%21%18%15%9%
198
January1st to 10thNight
25%8%16%26%20%6%
760
11th to 20thNight
24%7%15%28%20%6%
760
21st to endNight
23%7%13%28%24%6%
836
February1st to 10thNight
23%7%16%26%23%4
760
11th to 20thNight
23%9%18%24%19%7%
744
21st to endNight
21%11%20%30%16%3
628
March1st to 10thNight
28%10%16%24%17%4
750
11th to 20thNight
24%7%16%29%19%4
720
21st to endNight
22%9%25%26%15%3
792
April1st to 10thNight
18%10%24%26%17%5%
720
11th to 20thNight
15%12%25%27%15%6%
711
21st to endNight
12%12%30%22%19%5%
682
May1st to 10thNight
7%10%28%28%20%7%
540
11th to 20thNight
8%5%23%37%22%6%
531
21st to endNight
9%10%24%29%23%5%
402
June1st to 10thNight
9%8%28%30%22%3
360
11th to 20thNight
311%25%38%21%2
360
21st to endNight
4221%42%26%5%
360
July1st to 10thNight
2320%34%32%9%
396
11th to 20thNight
2114%32%39%13%
522
21st to endNight
2110%30%39%18%
591
August1st to 10thNight
2213%34%36%13%
537
11th to 20thNight
1112%31%39%16%
544
21st to endNight
3210%28%45%13%
792
September1st to 10thNight
1315%26%39%16%
720
11th to 20thNight
6%412%31%36%10%
720
21st to endNight
6%6%13%27%35%13%
720
October1st to 10thNight
7%7%14%28%32%13%
720
11th to 20thNight
9%5%11%25%37%13%
720
21st to endNight
15%411%25%33%13%
792
November1st to 10thNight
15%6%15%23%31%10%
740
11th to 20thNight
19%5%13%28%29%7%
760
21st to endNight
16%6%16%29%26%7%
760
December1st to 10thNight
27%412%27%21%8%
760
11th to 20thNight
29%6%15%26%19%4
760
21st to endNight
26%8%19%26%17%4
836
Page generated at 2024-03-05 04:24:05. Version ac07

Copyright © 2024 Attilla Danko.


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