Garden City
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Garden City clear sky chart from 2005-11-06 to 2024-01-17.

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
43%
24459
28%
74286
15%
24402
55%
24402
39%
40159

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
41%
950
29%
2647
14%
946
52%
946
41%
1469
January11th to 20thNight
41%
935
31%
2581
16%
935
52%
935
43%
1423
January21st to endNight
41%
962
34%
2546
15%
962
53%
962
45%
1406
February1st to 10thNight
37%
720
26%
2160
14%
720
48%
720
34%
1219
February11th to 20thNight
28%
702
25%
2098
9%
700
41%
700
33%
1202
February21st to endNight
30%
592
36%
1776
13%
592
49%
592
39%
936
March1st to 10thNight
32%
720
29%
2160
11%
720
47%
720
39%
1136
March11th to 20thNight
39%
589
26%
2029
16%
589
52%
589
33%
1064
March21st to endNight
25%
594
25%
2134
10%
594
44%
594
25%
1190
April1st to 10thNight
27%
540
27%
1800
11%
540
48%
540
35%
917
April11th to 20thNight
24%
533
24%
1777
11%
533
44%
533
29%
973
April21st to endNight
30%
540
25%
1666
13%
540
48%
540
31%
950
May1st to 10thNight
30%
540
22%
1620
12%
540
46%
540
31%
955
May11th to 20thNight
39%
531
19%
1593
13%
531
49%
531
33%
937
May21st to endNight
29%
583
17%
1745
6%
582
42%
582
30%
1049
June1st to 10thNight
43%
540
22%
1554
12%
540
53%
540
42%
837
June11th to 20thNight
34%
540
25%
1440
8%
540
47%
540
42%
805
June21st to endNight
47%
540
24%
1440
14%
540
55%
540
43%
820
July1st to 10thNight
56%
525
21%
1400
13%
525
62%
525
40%
843
July11th to 20thNight
64%
522
26%
1405
18%
522
70%
522
53%
740
July21st to endNight
66%
591
21%
1673
19%
558
68%
558
35%
979
August1st to 10thNight
63%
537
22%
1601
21%
534
67%
534
38%
915
August11th to 20thNight
57%
534
24%
1734
23%
534
66%
534
37%
943
August21st to endNight
61%
594
27%
1980
26%
594
68%
594
43%
980
September1st to 10thNight
56%
540
28%
1837
24%
540
67%
540
40%
953
September11th to 20thNight
48%
540
31%
1980
21%
540
65%
540
40%
928
September21st to endNight
51%
540
34%
1980
27%
540
64%
540
42%
916
October1st to 10thNight
45%
540
33%
1980
23%
540
58%
540
36%
999
October11th to 20thNight
42%
592
38%
2032
21%
592
59%
592
47%
917
October21st to endNight
47%
990
32%
2574
14%
990
56%
990
48%
1404
November1st to 10thNight
50%
925
34%
2405
13%
925
61%
925
55%
1229
November11th to 20thNight
44%
950
38%
2470
15%
950
58%
950
54%
1270
November21st to endNight
50%
950
33%
2470
16%
950
59%
950
46%
1368
December1st to 10thNight
45%
950
31%
2470
14%
950
55%
950
45%
1392
December11th to 20thNight
41%
949
33%
2857
16%
948
53%
948
39%
1538
December21st to endNight
38%
1039
22%
4672
16%
1026
51%
1026
24%
2557

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
7%5%2442345%7%58%
75040
Night
6%5%2442445%7%57%
74781
TransparencyDay
26%5%11%26%24%8%
74757
Night
26%5%11%25%24%9%
74587
SeeingDay
9%7%29%34%17%3
14390
Night
8%9%36%36%10%1
24469

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%5%24323347%63%
1518
11th to 20thDay
6%6%25%324346%58%
1520
21st to endDay
45%25%42436%5%60%
1826
February1st to 10thDay
5%8%36%423347%54%
1800
11th to 20thDay
45%26%5%25%5%5%7%55%
1749
21st to endDay
5%5%26%43345%6%59%
1480
March1st to 10thDay
5%5%2433345%8%57%
1800
11th to 20thDay
10%5%25%323345%56%
1930
21st to endDay
10%5%3443345%7%54%
2218
April1st to 10thDay
9%42332335%6%61%
2160
11th to 20thDay
11%5%2342445%7%53%
2131
21st to endDay
11%5%1442446%7%52%
2291
May1st to 10thDay
10%42442445%7%53%
2340
11th to 20thDay
10%5%143345%5%8%52%
2302
21st to endDay
8%4135%345%6%8%52%
2531
June1st to 10thDay
431332446%10%60%
2400
11th to 20thDay
5%32232445%8%62%
2520
21st to endDay
321343335%9%63%
2520
July1st to 10thDay
6%313435%46%9%57%
2520
11th to 20thDay
32123335%7%9%61%
2502
21st to endDay
5%41443446%12%53%
2546
August1st to 10thDay
5%324435%5%7%10%53%
2328
11th to 20thDay
6%42443445%9%55%
2163
21st to endDay
5%313334448%62%
2376
September1st to 10thDay
9%413323447%59%
2121
11th to 20thDay
7%31432445%6%62%
1980
21st to endDay
6%313323346%65%
1980
October1st to 10thDay
12%424322245%60%
1980
11th to 20thDay
7%31231324470%
1906
21st to endDay
9%6%23322335%64%
1782
November1st to 10thDay
6%413322346%66%
1673
11th to 20thDay
3424323336%67%
1710
21st to endDay
7%5%24323335%63%
1710
December1st to 10thDay
5%5%25%42345%7%58%
1710
11th to 20thDay
7%5%24322346%61%
2161
21st to endDay
6%14%46%433345%47%
2856
January1st to 10thNight
46%35%433346%59%
2647
11th to 20thNight
5%5%25%424346%61%
2581
21st to endNight
45%3342445%6%62%
2546
February1st to 10thNight
6%8%35%5%33346%55%
2160
11th to 20thNight
5%6%36%5%35%45%6%53%
2098
21st to endNight
6%5%25%323346%61%
1776
March1st to 10thNight
6%5%2343445%8%57%
2160
11th to 20thNight
9%5%34323347%57%
2029
21st to endNight
10%6%245%345%5%8%49%
2134
April1st to 10thNight
7%42442446%9%55%
1800
11th to 20thNight
10%5%234335%6%7%52%
1777
21st to endNight
10%5%3442445%8%52%
1666
May1st to 10thNight
10%6%24425%46%8%50%
1620
11th to 20thNight
9%4245%2446%9%51%
1593
21st to endNight
10%414435%5%6%9%49%
1745
June1st to 10thNight
5%213325%6%6%12%54%
1554
11th to 20thNight
432443446%10%57%
1440
21st to endNight
5%2145%35%5%6%10%54%
1440
July1st to 10thNight
5%426%4345%6%10%50%
1440
11th to 20thNight
32123245%7%9%61%
1453
21st to endNight
6%425%435%5%7%11%48%
1772
August1st to 10thNight
6%3345%35%5%7%12%47%
1611
11th to 20thNight
7%4233236%6%10%52%
1734
21st to endNight
43234235%6%8%60%
1980
September1st to 10thNight
6%41333445%8%58%
1837
11th to 20thNight
7%21332336%9%60%
1980
21st to endNight
7%31332245%6%64%
1980
October1st to 10thNight
10%5%23322345%60%
1980
11th to 20thNight
7%21322332471%
2032
21st to endNight
8%41232333466%
2574
November1st to 10thNight
4213322447%69%
2405
11th to 20thNight
4323323346%69%
2470
21st to endNight
6%42333335%7%60%
2470
December1st to 10thNight
5%5%2442345%7%59%
2470
11th to 20thNight
6%5%2442345%6%60%
3036
21st to endNight
7%10%35%5%24446%50%
4791

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
23%312%32%25%5%
1519
11th to 20thDay
28%311%29%23%6%
1520
21st to endDay
27%310%33%22%6%
1826
February1st to 10thDay
32%311%28%18%8%
1800
11th to 20thDay
29%412%28%19%9%
1759
21st to endDay
27%39%25%24%12%
1480
March1st to 10thDay
26%310%24%23%14%
1800
11th to 20thDay
31%310%21%27%8%
1930
21st to endDay
31%413%28%18%6%
2218
April1st to 10thDay
25%410%23%26%12%
2160
11th to 20thDay
32%5%11%25%20%7%
2134
21st to endDay
32%5%10%25%24%5%
2291
May1st to 10thDay
31%5%10%26%22%6%
2340
11th to 20thDay
29%7%17%30%15%2
2306
21st to endDay
30%8%15%25%16%6%
2531
June1st to 10thDay
20%6%20%30%18%6%
2400
11th to 20thDay
21%6%11%24%26%12%
2520
21st to endDay
20%5%11%28%26%10%
2520
July1st to 10thDay
26%6%13%24%27%4
2451
11th to 20thDay
17%6%11%31%27%8%
2427
21st to endDay
25%7%17%31%18%2
2405
August1st to 10thDay
24%9%17%29%16%5%
2314
11th to 20thDay
26%6%10%29%22%7%
2163
21st to endDay
21%6%11%24%28%10%
2376
September1st to 10thDay
26%6%9%23%24%13%
2121
11th to 20thDay
24%48%24%29%11%
1980
21st to endDay
21%49%26%28%12%
1980
October1st to 10thDay
29%410%21%27%9%
1980
11th to 20thDay
20%37%23%32%16%
1906
21st to endDay
25%28%24%30%11%
1782
November1st to 10thDay
21%39%24%31%13%
1673
11th to 20thDay
20%38%29%30%11%
1710
21st to endDay
26%37%19%32%14%
1710
December1st to 10thDay
26%412%29%24%6%
1710
11th to 20thDay
25%38%33%26%6%
2159
21st to endDay
41%38%21%21%6%
2856
January1st to 10thNight
27%310%28%26%5%
2647
11th to 20thNight
26%49%26%28%8%
2581
21st to endNight
24%49%32%24%7%
2546
February1st to 10thNight
32%311%23%22%8%
2160
11th to 20thNight
32%5%12%22%22%7%
2098
21st to endNight
26%37%22%27%15%
1776
March1st to 10thNight
25%48%22%27%13%
2160
11th to 20thNight
29%410%22%23%12%
2029
21st to endNight
33%5%12%24%19%6%
2134
April1st to 10thNight
26%412%23%23%12%
1800
11th to 20thNight
30%5%12%26%19%8%
1777
21st to endNight
31%6%12%24%23%4
1666
May1st to 10thNight
32%6%13%22%20%8%
1620
11th to 20thNight
29%9%17%23%19%4
1594
21st to endNight
32%8%19%23%14%6%
1746
June1st to 10thNight
21%8%19%31%15%5%
1554
11th to 20thNight
23%7%14%25%23%9%
1440
21st to endNight
24%7%13%25%22%10%
1440
July1st to 10thNight
28%7%13%21%24%6%
1400
11th to 20thNight
17%7%15%28%25%9%
1405
21st to endNight
29%8%14%26%19%4
1673
August1st to 10thNight
29%6%17%28%16%4
1601
11th to 20thNight
26%8%13%30%16%7%
1734
21st to endNight
21%6%14%24%24%10%
1980
September1st to 10thNight
24%6%10%22%25%12%
1837
11th to 20thNight
22%5%11%21%29%11%
1980
21st to endNight
21%47%22%31%14%
1980
October1st to 10thNight
26%5%10%20%28%11%
1980
11th to 20thNight
19%37%19%32%20%
2032
21st to endNight
23%38%22%28%16%
2574
November1st to 10thNight
17%49%25%28%17%
2405
11th to 20thNight
19%37%26%33%13%
2470
21st to endNight
24%39%22%27%15%
2470
December1st to 10thNight
25%412%29%23%8%
2470
11th to 20thNight
26%37%28%30%5%
3037
21st to endNight
35%410%26%21%5%
4791

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
9%7%36%32%13%2
270
11th to 20thDay
14%6%39%27%12%2
258
21st to endDay
5%9%41%36%8%2
264
February1st to 10thDay
7%10%49%27%7%
240
11th to 20thDay
8%11%45%25%10%1
240
21st to endDay
5%16%47%27%5%
198
March1st to 10thDay
9%11%38%34%8%
240
11th to 20thDay
16%14%34%25%10%2
240
21st to endDay
13%19%36%25%5%1
304
April1st to 10thDay
12%14%42%25%6%1
420
11th to 20thDay
16%18%35%25%5%1
412
21st to endDay
15%14%38%25%8%1
551
May1st to 10thDay
11%10%36%30%12%1
603
11th to 20thDay
16%9%27%31%14%3
625
21st to endDay
12%9%37%29%12%1
679
June1st to 10thDay
45%27%37%19%7%
630
11th to 20thDay
5%6%33%37%16%2
630
21st to endDay
3428%41%21%2
630
July1st to 10thDay
8%217%42%27%5%
621
11th to 20thDay
2115%43%30%8%
618
21st to endDay
7%113%38%34%7%
684
August1st to 10thDay
6%114%42%32%5%
626
11th to 20thDay
4121%45%26%3
477
21st to endDay
5%320%40%26%6%
495
September1st to 10thDay
10%220%40%24%4
411
11th to 20thDay
4324%36%25%8%
270
21st to endDay
9%7%26%34%19%5%
270
October1st to 10thDay
17%6%20%33%18%6%
270
11th to 20thDay
5%440%29%18%4
270
21st to endDay
16%10%30%25%15%3
297
November1st to 10thDay
9%7%34%30%16%4
270
11th to 20thDay
7%11%34%31%15%2
270
21st to endDay
15%11%28%28%15%3
270
December1st to 10thDay
8%6%34%32%15%4
270
11th to 20thDay
10%11%35%33%11%1
270
21st to endDay
15%12%34%32%6%1
297
January1st to 10thNight
7%8%37%38%9%1
950
11th to 20thNight
8%8%37%36%10%1
935
21st to endNight
6%8%41%36%7%1
962
February1st to 10thNight
10%10%38%35%6%1
720
11th to 20thNight
8%10%50%26%6%
704
21st to endNight
9%13%46%29%3
592
March1st to 10thNight
8%13%43%31%6%
720
11th to 20thNight
13%11%35%31%9%1
589
21st to endNight
14%14%44%24%4
594
April1st to 10thNight
9%16%45%26%4
540
11th to 20thNight
13%17%43%23%3
533
21st to endNight
13%14%40%23%9%1
540
May1st to 10thNight
12%11%43%27%6%
540
11th to 20thNight
11%10%36%31%11%1
531
21st to endNight
10%14%43%26%8%
584
June1st to 10thNight
48%41%33%13%1
540
11th to 20thNight
411%46%32%6%1
540
21st to endNight
5%5%38%42%10%
540
July1st to 10thNight
5%228%46%18%
525
11th to 20thNight
4127%47%20%1
522
21st to endNight
8%217%52%20%1
591
August1st to 10thNight
8%219%48%22%1
537
11th to 20thNight
9%227%48%14%
534
21st to endNight
4328%44%19%1
594
September1st to 10thNight
7%131%46%14%
540
11th to 20thNight
8%337%39%13%1
540
21st to endNight
8%8%31%39%14%
540
October1st to 10thNight
13%8%31%37%11%
540
11th to 20thNight
8%9%39%33%11%1
592
21st to endNight
11%7%33%33%16%1
990
November1st to 10thNight
6%8%33%43%10%1
925
11th to 20thNight
6%9%39%36%10%
950
21st to endNight
9%10%29%39%11%2
950
December1st to 10thNight
8%8%35%40%8%1
950
11th to 20thNight
9%11%34%37%8%
950
21st to endNight
11%11%36%35%8%
1045
Page generated at 2024-01-14 08:54:59. Version ac07

Copyright 2024 Attilla Danko


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