Sun City West
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sun City West clear sky chart from 2005-11-06 to 2024-01-10.

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
76%
24132
38%
74323
33%
24085
81%
24085
56%
34402

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
72%
758
35%
2456
34%
756
78%
756
48%
1175
January11th to 20thNight
73%
720
38%
2340
37%
720
79%
720
48%
1114
January21st to endNight
61%
792
38%
2574
33%
792
73%
792
43%
1292
February1st to 10thNight
69%
720
39%
2232
35%
720
80%
720
55%
1027
February11th to 20thNight
68%
700
36%
2099
33%
700
76%
700
48%
1061
February21st to endNight
64%
592
36%
1776
34%
592
71%
592
48%
890
March1st to 10thNight
65%
720
39%
1994
29%
720
75%
720
56%
977
March11th to 20thNight
72%
720
39%
1980
33%
720
78%
720
58%
979
March21st to endNight
70%
792
40%
2178
29%
792
79%
792
61%
1033
April1st to 10thNight
73%
720
37%
1980
25%
720
80%
720
63%
922
April11th to 20thNight
65%
636
40%
1856
27%
636
76%
636
63%
818
April21st to endNight
71%
540
48%
1620
36%
540
81%
540
73%
644
May1st to 10thNight
70%
540
42%
1620
31%
540
79%
540
67%
682
May11th to 20thNight
75%
531
42%
1594
34%
531
80%
531
71%
645
May21st to endNight
78%
582
41%
1746
31%
582
83%
582
76%
682
June1st to 10thNight
82%
540
38%
1620
31%
540
85%
540
74%
652
June11th to 20thNight
84%
540
40%
1620
32%
540
88%
540
84%
602
June21st to endNight
86%
540
35%
1620
31%
540
87%
540
69%
676
July1st to 10thNight
85%
525
31%
1575
25%
525
86%
525
59%
726
July11th to 20thNight
86%
522
31%
1566
26%
522
86%
522
52%
775
July21st to endNight
82%
591
28%
1674
23%
558
83%
558
41%
926
August1st to 10thNight
87%
537
34%
1602
28%
534
88%
534
55%
769
August11th to 20thNight
87%
534
35%
1602
31%
534
87%
534
47%
816
August21st to endNight
85%
744
35%
2021
30%
744
85%
744
54%
1053
September1st to 10thNight
82%
720
34%
1980
31%
720
83%
720
53%
1018
September11th to 20thNight
86%
720
44%
1980
38%
720
88%
720
69%
886
September21st to endNight
83%
720
42%
1980
32%
720
88%
720
67%
910
October1st to 10thNight
79%
720
41%
1988
33%
720
84%
720
63%
940
October11th to 20thNight
84%
720
46%
2160
42%
720
88%
720
76%
849
October21st to endNight
80%
792
46%
2376
38%
792
88%
792
73%
946
November1st to 10thNight
83%
740
44%
2220
41%
740
86%
740
65%
964
November11th to 20thNight
83%
760
42%
2470
42%
760
87%
760
64%
1008
November21st to endNight
72%
760
40%
2470
38%
760
79%
760
52%
1113
December1st to 10thNight
73%
760
39%
2470
38%
760
79%
760
51%
1137
December11th to 20thNight
69%
759
35%
2935
36%
758
75%
758
34%
1546
December21st to endNight
66%
825
24%
4349
36%
817
72%
817
26%
2149

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
3213323346%71%
74911
Night
4213323346%69%
74807
TransparencyDay
17%2312%25%42%
74638
Night
18%2311%23%43%
74602
SeeingDay
4415%31%32%14%
13898
Night
4212%43%35%3
24152

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
5%414313437%65%
1699
11th to 20thDay
5%314312445%68%
1620
21st to endDay
7%314323236%65%
1782
February1st to 10thDay
3412212347%69%
1724
11th to 20thDay
6%314413346%63%
1750
21st to endDay
5%313313446%67%
1480
March1st to 10thDay
4312334447%64%
1966
11th to 20thDay
4322313346%68%
1980
21st to endDay
3212323335%72%
2178
April1st to 10thDay
2112312448%72%
1980
11th to 20thDay
2112212335%79%
2047
21st to endDay
1112212236%80%
2340
May1st to 10thDay
1112212236%80%
2340
11th to 20thDay
1112112235%79%
2301
21st to endDay
211111111387%
2530
June1st to 10thDay
111221223483%
2340
11th to 20thDay
1111112389%
2340
21st to endDay
1112222225%81%
2340
July1st to 10thDay
111322345%7%70%
2340
11th to 20thDay
3214425%6%9%10%54%
2340
21st to endDay
45%245%35%6%7%11%48%
2545
August1st to 10thDay
431332445%7%62%
2328
11th to 20thDay
23232245%7%9%61%
2299
21st to endDay
311332445%7%66%
2330
September1st to 10thDay
5%312323347%68%
1980
11th to 20thDay
211121123480%
1980
21st to endDay
221322233377%
1980
October1st to 10thDay
3112223345%75%
1972
11th to 20thDay
21111222485%
1800
21st to endDay
111221233481%
1980
November1st to 10thDay
1112222345%78%
1855
11th to 20thDay
2212312345%76%
1710
21st to endDay
5%313323346%67%
1710
December1st to 10thDay
5%4245%24445%62%
1710
11th to 20thDay
5%325%5%335%8%7%54%
2169
21st to endDay
9%6%25%423447%54%
3146
January1st to 10thNight
5%31332445%6%63%
2456
11th to 20thNight
6%323323335%67%
2340
21st to endNight
8%41332344463%
2574
February1st to 10thNight
3313323345%70%
2232
11th to 20thNight
6%424323446%64%
2098
21st to endNight
7%313333435%65%
1776
March1st to 10thNight
432331435%7%66%
1994
11th to 20thNight
6%313312335%70%
1980
21st to endNight
421222335%7%70%
2178
April1st to 10thNight
2112223446%72%
1980
11th to 20thNight
32222234476%
1856
21st to endNight
11111133482%
1620
May1st to 10thNight
1112312345%77%
1620
11th to 20thNight
111211232481%
1594
21st to endNight
21111111388%
1746
June1st to 10thNight
211112335%81%
1620
11th to 20thNight
11212488%
1620
21st to endNight
21221223480%
1620
July1st to 10thNight
11134235%6%9%65%
1620
11th to 20thNight
12134245%8%10%60%
1620
21st to endNight
33246%46%5%7%12%48%
1773
August1st to 10thNight
12133345%7%9%62%
1611
11th to 20thNight
2213436%5%7%9%58%
1602
21st to endNight
22235%3446%8%61%
2021
September1st to 10thNight
33134246%7%8%60%
1980
11th to 20thNight
111232243477%
1980
21st to endNight
2212213335%77%
1980
October1st to 10thNight
3213223235%74%
1988
11th to 20thNight
211211123484%
2160
21st to endNight
1111112225%82%
2376
November1st to 10thNight
3212223245%74%
2220
11th to 20thNight
2212222235%77%
2470
21st to endNight
5%213223346%68%
2470
December1st to 10thNight
6%223223346%67%
2470
11th to 20thNight
6%435%5%34446%55%
3041
21st to endNight
8%6%245%33445%57%
4521

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
22%2418%30%23%
1700
11th to 20thDay
21%2313%29%32%
1620
21st to endDay
24%2216%28%28%
1782
February1st to 10thDay
17%1416%26%36%
1724
11th to 20thDay
23%3315%26%30%
1760
21st to endDay
20%3313%32%30%
1480
March1st to 10thDay
21%2111%28%35%
1966
11th to 20thDay
19%2212%28%37%
1980
21st to endDay
18%2210%33%36%
2178
April1st to 10thDay
13%219%37%39%
1980
11th to 20thDay
11%218%27%52%
2050
21st to endDay
10%127%24%56%
2340
May1st to 10thDay
9%118%25%56%
2340
11th to 20thDay
10%217%21%58%
2304
21st to endDay
7%1422%66%
2530
June1st to 10thDay
9%1319%68%
2340
11th to 20thDay
5%1129%83%
2340
21st to endDay
10%125%13%70%
2340
July1st to 10thDay
15%35%10%18%50%
2276
11th to 20thDay
21%5%9%20%26%18%
2271
21st to endDay
28%411%23%18%16%
2404
August1st to 10thDay
21%37%16%19%35%
2313
11th to 20thDay
20%35%20%26%26%
2299
21st to endDay
18%36%15%30%28%
2330
September1st to 10thDay
18%3412%25%38%
1980
11th to 20thDay
11%216%27%53%
1980
21st to endDay
13%316%22%54%
1980
October1st to 10thDay
14%1313%24%45%
1972
11th to 20thDay
8%127%25%58%
1800
21st to endDay
10%138%28%50%
1980
November1st to 10thDay
11%1114%31%42%
1855
11th to 20thDay
13%1111%28%44%
1710
21st to endDay
20%2211%29%36%
1710
December1st to 10thDay
26%2315%23%31%
1710
11th to 20thDay
28%25%21%24%20%
2168
21st to endDay
33%15%24%25%13%
3146
January1st to 10thNight
23%2416%29%27%
2456
11th to 20thNight
22%2212%28%34%
2340
21st to endNight
26%2213%25%31%
2574
February1st to 10thNight
19%1312%26%40%
2232
11th to 20thNight
24%2412%25%33%
2099
21st to endNight
23%229%28%36%
1776
March1st to 10thNight
19%2213%24%41%
1994
11th to 20thNight
19%119%25%44%
1980
21st to endNight
16%239%32%39%
2178
April1st to 10thNight
14%219%28%47%
1980
11th to 20thNight
13%115%25%55%
1856
21st to endNight
8%216%23%60%
1620
May1st to 10thNight
11%127%22%56%
1620
11th to 20thNight
10%116%20%62%
1595
21st to endNight
8%1418%69%
1746
June1st to 10thNight
9%1216%71%
1620
11th to 20thNight
5%11210%81%
1620
21st to endNight
11%11310%73%
1620
July1st to 10thNight
15%35%11%16%50%
1575
11th to 20thNight
19%5%7%21%24%24%
1566
21st to endNight
28%5%11%21%18%18%
1674
August1st to 10thNight
18%36%19%19%34%
1602
11th to 20thNight
22%47%19%18%29%
1602
21st to endNight
21%37%14%25%31%
2021
September1st to 10thNight
20%37%16%19%35%
1980
11th to 20thNight
12%228%21%54%
1980
21st to endNight
13%217%18%59%
1980
October1st to 10thNight
16%1312%19%49%
1988
11th to 20thNight
8%117%20%63%
2160
21st to endNight
8%129%20%59%
2376
November1st to 10thNight
14%118%30%46%
2220
11th to 20thNight
13%1110%26%48%
2470
21st to endNight
19%2310%25%40%
2470
December1st to 10thNight
20%2317%22%36%
2470
11th to 20thNight
31%2413%27%24%
3041
21st to endNight
33%2320%24%18%
4521

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
10%215%39%28%5%
267
11th to 20thDay
11%210%39%28%9%
240
21st to endDay
7%317%38%25%9%
264
February1st to 10thDay
5%319%34%31%9%
344
11th to 20thDay
9%7%22%37%22%4
415
21st to endDay
8%9%29%34%16%4
346
March1st to 10thDay
6%8%22%37%21%5%
420
11th to 20thDay
5%6%22%33%25%10%
420
21st to endDay
49%28%34%20%5%
462
April1st to 10thDay
49%20%31%26%9%
420
11th to 20thDay
310%28%29%24%6%
412
21st to endDay
39%24%29%23%12%
420
May1st to 10thDay
26%24%31%26%11%
423
11th to 20thDay
25%19%36%28%10%
448
21st to endDay
25%20%32%31%10%
485
June1st to 10thDay
1317%31%33%15%
450
11th to 20thDay
2216%29%32%18%
450
21st to endDay
110%35%39%14%
450
July1st to 10thDay
116%31%39%23%
446
11th to 20thDay
31425%39%28%
444
21st to endDay
5%1323%38%30%
487
August1st to 10thDay
21426%41%26%
447
11th to 20thDay
21324%43%26%
437
21st to endDay
21320%44%30%
495
September1st to 10thDay
417%26%43%19%
450
11th to 20thDay
410%32%38%16%
450
21st to endDay
4213%31%30%20%
450
October1st to 10thDay
3215%31%38%11%
442
11th to 20thDay
2115%28%38%16%
270
21st to endDay
1410%29%40%15%
297
November1st to 10thDay
2411%33%40%10%
270
11th to 20thDay
419%36%40%10%
270
21st to endDay
6%316%37%27%11%
270
December1st to 10thDay
8%311%39%30%10%
270
11th to 20thDay
1117%39%35%6%
270
21st to endDay
14%315%36%26%6%
297
January1st to 10thNight
7%113%49%27%3
760
11th to 20thNight
7%212%47%28%4
720
21st to endNight
9%220%43%23%3
792
February1st to 10thNight
4318%44%26%4
720
11th to 20thNight
8%215%54%20%1
704
21st to endNight
8%419%47%21%2
592
March1st to 10thNight
5%421%49%21%1
720
11th to 20thNight
7%314%43%31%4
720
21st to endNight
5%317%47%26%2
792
April1st to 10thNight
2417%50%24%3
720
11th to 20thNight
35%23%44%23%2
636
21st to endNight
2322%47%23%3
540
May1st to 10thNight
1322%47%24%2
540
11th to 20thNight
1218%46%32%2
531
21st to endNight
3216%49%29%2
584
June1st to 10thNight
2112%54%30%1
540
11th to 20thNight
1113%52%32%1
540
21st to endNight
117%48%40%3
540
July1st to 10thNight
215%40%50%3
525
11th to 20thNight
21329%61%4
522
21st to endNight
41328%58%6%
591
August1st to 10thNight
21325%60%9%
537
11th to 20thNight
21227%63%4
534
21st to endNight
31422%60%11%
744
September1st to 10thNight
425%28%54%7%
720
11th to 20thNight
117%35%51%5%
720
21st to endNight
328%40%42%5%
720
October1st to 10thNight
3210%47%36%2
720
11th to 20thNight
319%48%37%3
720
21st to endNight
1213%41%36%7%
792
November1st to 10thNight
319%48%35%4
740
11th to 20thNight
3110%44%38%4
760
21st to endNight
6%214%45%30%3
760
December1st to 10thNight
6%313%46%31%1
760
11th to 20thNight
8%313%49%26%2
760
21st to endNight
8%315%49%22%3
836
Page generated at 2024-01-07 08:06:53. Version ac07

Copyright 2024 Attilla Danko


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