Victoria Beach
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Victoria Beach clear sky chart from 2005-11-06 to 2024-02-05.

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
42%
25203
11%
80758
8%
25143
45%
25143
18%
58105

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
33%
935
5%
4716
5%
926
36%
926
7%
3632
January11th to 20thNight
35%
934
6%
4732
7%
930
37%
930
7%
3931
January21st to endNight
35%
1029
6%
4975
6%
1023
38%
1023
8%
3884
February1st to 10thNight
45%
923
13%
2484
8%
923
47%
923
20%
1847
February11th to 20thNight
47%
874
17%
2274
9%
874
51%
874
26%
1591
February21st to endNight
42%
722
18%
1906
10%
722
46%
722
22%
1382
March1st to 10thNight
45%
663
14%
2106
12%
663
47%
663
20%
1473
March11th to 20thNight
45%
540
18%
1980
15%
540
54%
540
24%
1215
March21st to endNight
45%
594
17%
2178
19%
594
50%
594
19%
1436
April1st to 10thNight
47%
540
19%
1752
20%
540
54%
540
25%
1096
April11th to 20thNight
48%
533
19%
1599
16%
533
53%
533
24%
1076
April21st to endNight
50%
540
15%
1620
10%
540
54%
540
26%
1052
May1st to 10thNight
45%
540
14%
1490
7%
540
47%
540
24%
1030
May11th to 20thNight
54%
531
13%
1280
8%
531
55%
531
33%
871
May21st to endNight
49%
584
8%
1358
6%
582
50%
582
28%
972
June1st to 10thNight
53%
540
4%
1260
4%
540
55%
540
27%
917
June11th to 20thNight
52%
540
2%
1260
4%
540
53%
540
33%
868
June21st to endNight
65%
540
1%
1260
3%
540
65%
540
36%
844
July1st to 10thNight
68%
525
5%
1225
5%
525
70%
525
48%
724
July11th to 20thNight
63%
522
7%
1218
5%
522
64%
522
40%
787
July21st to endNight
66%
591
14%
1302
9%
558
66%
558
46%
801
August1st to 10thNight
62%
537
16%
1454
7%
534
64%
534
37%
879
August11th to 20thNight
63%
534
15%
1600
10%
534
66%
534
34%
942
August21st to endNight
55%
594
17%
1782
17%
594
58%
594
30%
1092
September1st to 10thNight
50%
540
16%
1712
16%
540
54%
540
30%
1034
September11th to 20thNight
48%
540
15%
1962
16%
540
52%
540
21%
1224
September21st to endNight
42%
540
18%
1980
15%
540
49%
540
21%
1255
October1st to 10thNight
34%
690
14%
2130
9%
690
38%
690
18%
1521
October11th to 20thNight
32%
746
14%
2186
8%
746
37%
746
15%
1640
October21st to endNight
27%
990
9%
2596
4%
990
30%
990
14%
2081
November1st to 10thNight
26%
925
9%
2591
4%
925
29%
925
12%
2099
November11th to 20thNight
22%
950
8%
2660
5%
950
25%
950
9%
2237
November21st to endNight
20%
950
5%
2793
2%
950
23%
950
9%
2340
December1st to 10thNight
32%
950
6%
2850
4%
950
34%
950
11%
2312
December11th to 20thNight
23%
948
9%
3437
5%
948
28%
948
9%
2591
December21st to endNight
30%
1029
6%
5050
5%
1026
34%
1026
8%
3429

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
11%9%48%7%45%5%6%7%34%
77681
Night
11%11%5%9%8%46%6%5%7%30%
81218
TransparencyDay
48%6%15%22%8%1
77363
Night
52%6%14%19%8%1
81069
SeeingDay
15%420%34%22%5%
15155
Night
17%423%35%18%3
25276

By Month

Percentage Cloud Cover NE (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%16%7%12%11%6%9%6%6%5%17%
2218
11th to 20thDay
5%9%6%16%15%7%9%7%8%6%12%
2220
21st to endDay
7%18%8%14%10%5%6%5%6%6%15%
2674
February1st to 10thDay
7%11%5%11%8%48%7%8%9%21%
1569
11th to 20thDay
9%9%49%8%49%6%6%9%28%
1574
21st to endDay
6%11%5%10%9%47%6%7%8%27%
1364
March1st to 10thDay
10%12%5%10%9%45%7%6%6%26%
1852
11th to 20thDay
9%9%49%7%46%5%7%6%34%
1980
21st to endDay
10%9%37%6%45%6%6%7%36%
2178
April1st to 10thDay
10%9%37%6%35%45%7%41%
2205
11th to 20thDay
10%8%36%5%45%5%6%8%40%
2312
21st to endDay
13%6%37%5%45%6%6%8%37%
2340
May1st to 10thDay
12%7%45%6%3445%7%43%
2468
11th to 20thDay
15%7%345%35%5%5%7%42%
2613
21st to endDay
17%7%25%5%35%5%6%6%38%
2918
June1st to 10thDay
16%6%25%5%35%5%5%8%41%
2700
11th to 20thDay
14%6%35%5%45%6%7%8%39%
2700
21st to endDay
12%5%36%5%45%5%7%9%39%
2700
July1st to 10thDay
8%425%5%35%46%8%50%
2700
11th to 20thDay
10%5%345%3446%10%46%
2700
21st to endDay
8%424425%5%6%10%49%
2939
August1st to 10thDay
8%5%245%35%5%6%9%48%
2475
11th to 20thDay
12%4244245%6%9%48%
2301
21st to endDay
14%6%35%5%345%5%7%44%
2574
September1st to 10thDay
12%6%25%4345%5%8%45%
2247
11th to 20thDay
16%8%35%6%445%6%8%35%
1994
21st to endDay
14%8%36%6%35%5%6%7%39%
1980
October1st to 10thDay
21%13%36%6%3446%7%28%
1811
11th to 20thDay
17%15%46%7%445%5%7%27%
1774
21st to endDay
19%15%5%10%7%45%5%5%5%19%
1760
November1st to 10thDay
18%13%6%12%9%4445%5%21%
1487
11th to 20thDay
10%17%7%16%11%35%33420%
1520
21st to endDay
12%14%6%13%12%5%6%445%18%
1383
December1st to 10thDay
9%12%7%15%12%7%8%6%5%5%14%
1330
11th to 20thDay
9%14%6%12%10%5%6%7%6%6%19%
1679
21st to endDay
9%11%5%10%8%7%7%8%6%8%22%
2442
January1st to 10thNight
6%12%7%13%10%8%8%7%5%7%18%
4737
11th to 20thNight
5%11%6%14%16%8%9%7%5%5%13%
4750
21st to endNight
8%18%7%12%8%46%6%5%6%18%
4992
February1st to 10thNight
6%12%5%9%8%5%7%8%6%6%28%
2484
11th to 20thNight
7%10%48%6%35%7%8%8%32%
2273
21st to endNight
5%11%6%10%7%47%6%5%6%33%
1906
March1st to 10thNight
8%11%49%7%45%6%6%7%32%
2095
11th to 20thNight
8%8%37%6%35%45%7%42%
1979
21st to endNight
12%10%47%6%34446%39%
2178
April1st to 10thNight
11%8%36%5%45%5%5%8%41%
1752
11th to 20thNight
13%9%47%6%35%5%6%7%36%
1599
21st to endNight
9%7%38%5%36%7%7%7%37%
1620
May1st to 10thNight
16%8%36%5%335%7%6%38%
1490
11th to 20thNight
14%6%26%5%35%5%5%8%41%
1280
21st to endNight
18%7%25%5%36%5%5%6%40%
1358
June1st to 10thNight
14%7%36%5%35%6%6%8%36%
1260
11th to 20thNight
14%6%35%435%5%6%8%41%
1260
21st to endNight
12%5%34435%5%8%12%40%
1260
July1st to 10thNight
7%2233245%7%9%55%
1260
11th to 20thNight
9%425%435%6%6%8%49%
1260
21st to endNight
7%42443446%9%53%
1379
August1st to 10thNight
7%425%5%35%45%8%51%
1461
11th to 20thNight
9%3235%35%5%7%8%50%
1600
21st to endNight
13%6%245%2445%8%46%
1782
September1st to 10thNight
13%6%25%5%3445%7%46%
1712
11th to 20thNight
16%7%25%4346%5%7%40%
1962
21st to endNight
16%7%37%5%345%5%8%37%
1980
October1st to 10thNight
18%12%46%6%345%47%33%
2130
11th to 20thNight
19%14%47%6%3445%6%27%
2186
21st to endNight
19%16%5%9%6%34446%24%
2596
November1st to 10thNight
15%16%6%11%7%46%5%4423%
2591
11th to 20thNight
12%17%8%14%10%44345%18%
2660
21st to endNight
14%14%8%13%12%5%5%44417%
2793
December1st to 10thNight
7%14%7%14%11%6%6%5%6%6%18%
2850
11th to 20thNight
8%15%7%11%9%45%7%5%6%22%
3518
21st to endNight
8%10%412%9%5%7%7%7%7%26%
5225

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
67%6%13%12%2
2219
11th to 20thDay
69%5%13%11%3
2220
21st to endDay
68%6%9%12%5%
2674
February1st to 10thDay
56%5%15%16%7%1
1569
11th to 20thDay
52%415%21%8%
1583
21st to endDay
52%6%14%20%8%
1364
March1st to 10thDay
57%6%13%17%7%1
1854
11th to 20thDay
48%7%16%21%8%
1980
21st to endDay
45%7%14%24%8%2
2178
April1st to 10thDay
43%5%13%25%13%1
2205
11th to 20thDay
42%5%11%23%17%2
2312
21st to endDay
44%6%15%25%9%1
2340
May1st to 10thDay
41%5%14%25%15%1
2468
11th to 20thDay
42%5%10%27%15%2
2617
21st to endDay
45%7%11%21%14%1
2918
June1st to 10thDay
42%7%14%26%10%1
2700
11th to 20thDay
41%8%15%23%11%1
2700
21st to endDay
40%8%19%25%8%
2700
July1st to 10thDay
31%7%17%32%13%
2626
11th to 20thDay
33%7%20%28%10%1
2619
21st to endDay
31%7%23%30%9%
2776
August1st to 10thDay
32%8%22%31%6%
2458
11th to 20thDay
33%7%22%31%5%1
2301
21st to endDay
38%6%18%30%6%
2574
September1st to 10thDay
37%7%19%30%7%
2247
11th to 20thDay
46%7%20%25%3
1994
21st to endDay
44%6%17%27%6%
1980
October1st to 10thDay
54%8%16%18%5%
1811
11th to 20thDay
56%8%14%19%3
1774
21st to endDay
65%6%16%11%2
1760
November1st to 10thDay
64%6%14%12%31
1487
11th to 20thDay
68%6%13%11%2
1520
21st to endDay
67%416%11%2
1383
December1st to 10thDay
72%5%11%10%2
1330
11th to 20thDay
62%7%16%11%4
1680
21st to endDay
55%10%12%16%7%
2442
January1st to 10thNight
64%6%12%13%4
4737
11th to 20thNight
71%5%9%12%2
4750
21st to endNight
65%6%13%13%4
4992
February1st to 10thNight
54%5%13%18%9%1
2484
11th to 20thNight
45%6%16%23%10%
2274
21st to endNight
52%411%22%11%
1906
March1st to 10thNight
50%5%14%19%11%1
2106
11th to 20thNight
41%5%15%27%11%2
1980
21st to endNight
47%6%11%21%13%2
2178
April1st to 10thNight
42%410%24%17%4
1752
11th to 20thNight
46%5%9%20%17%3
1599
21st to endNight
43%5%11%25%15%1
1620
May1st to 10thNight
46%6%8%26%14%1
1490
11th to 20thNight
41%410%27%15%3
1281
21st to endNight
46%5%12%18%17%3
1358
June1st to 10thNight
45%7%14%25%9%1
1260
11th to 20thNight
40%5%15%25%13%2
1260
21st to endNight
35%7%21%27%9%1
1260
July1st to 10thNight
23%7%16%37%16%1
1225
11th to 20thNight
31%7%18%30%12%2
1218
21st to endNight
27%6%18%37%12%1
1302
August1st to 10thNight
31%6%17%35%10%1
1454
11th to 20thNight
30%7%23%29%10%
1600
21st to endNight
37%6%18%30%9%1
1782
September1st to 10thNight
37%5%17%31%10%
1712
11th to 20thNight
42%6%18%25%8%1
1962
21st to endNight
44%6%16%27%8%
1980
October1st to 10thNight
50%7%15%20%8%
2130
11th to 20thNight
57%5%13%20%4
2186
21st to endNight
61%6%14%15%3
2596
November1st to 10thNight
63%7%13%12%4
2591
11th to 20thNight
69%7%11%9%4
2660
21st to endNight
71%413%9%2
2793
December1st to 10thNight
65%6%15%10%3
2850
11th to 20thNight
60%6%15%13%6%
3516
21st to endNight
54%6%12%19%8%1
5225

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
11%431%33%17%4
270
11th to 20thDay
10%6%21%41%20%2
270
21st to endDay
18%419%35%19%5%
297
February1st to 10thDay
14%427%38%13%4
252
11th to 20thDay
13%5%28%31%16%7%
240
21st to endDay
6%325%39%26%2
198
March1st to 10thDay
10%419%39%26%3
240
11th to 20thDay
14%5%22%38%18%4
240
21st to endDay
17%223%31%22%5%
264
April1st to 10thDay
12%421%40%20%3
465
11th to 20thDay
16%322%34%21%4
590
21st to endDay
14%319%38%21%4
600
May1st to 10thDay
13%320%36%24%3
603
11th to 20thDay
17%415%33%24%7%
625
21st to endDay
19%415%29%28%6%
679
June1st to 10thDay
18%416%34%22%7%
630
11th to 20thDay
16%322%32%23%4
630
21st to endDay
13%413%34%27%9%
630
July1st to 10thDay
9%418%36%26%8%
621
11th to 20thDay
11%5%18%32%27%8%
618
21st to endDay
9%215%35%30%10%
684
August1st to 10thDay
10%417%35%26%9%
626
11th to 20thDay
12%414%31%28%11%
615
21st to endDay
16%416%31%27%6%
693
September1st to 10thDay
15%423%35%20%4
537
11th to 20thDay
18%7%19%38%13%4
284
21st to endDay
23%7%23%33%14%1
270
October1st to 10thDay
23%6%21%28%17%4
270
11th to 20thDay
17%8%24%38%12%1
270
21st to endDay
30%8%20%26%13%2
297
November1st to 10thDay
21%7%24%33%14%1
270
11th to 20thDay
17%8%36%27%10%2
270
21st to endDay
21%9%27%37%6%
270
December1st to 10thDay
14%329%35%14%4
270
11th to 20thDay
17%6%33%32%10%3
270
21st to endDay
13%421%39%18%4
297
January1st to 10thNight
13%328%35%18%3
950
11th to 20thNight
14%5%24%40%15%3
950
21st to endNight
16%423%40%15%2
1045
February1st to 10thNight
13%323%41%18%2
923
11th to 20thNight
11%323%38%20%4
879
21st to endNight
10%326%37%22%2
722
March1st to 10thNight
14%322%36%22%3
666
11th to 20thNight
14%328%39%15%2
540
21st to endNight
18%421%34%19%5%
594
April1st to 10thNight
16%225%38%16%3
540
11th to 20thNight
16%420%37%20%3
533
21st to endNight
12%123%43%18%2
540
May1st to 10thNight
18%322%40%15%2
540
11th to 20thNight
17%317%38%21%4
531
21st to endNight
21%317%38%19%2
584
June1st to 10thNight
19%216%35%23%4
540
11th to 20thNight
17%419%34%23%3
540
21st to endNight
13%311%38%30%5%
540
July1st to 10thNight
7%217%39%29%4
525
11th to 20thNight
10%319%37%26%5%
522
21st to endNight
9%315%34%32%7%
591
August1st to 10thNight
9%417%38%28%4
537
11th to 20thNight
10%415%36%27%8%
534
21st to endNight
18%218%34%25%4
594
September1st to 10thNight
17%423%35%18%4
540
11th to 20thNight
19%422%37%16%1
540
21st to endNight
20%426%33%15%2
540
October1st to 10thNight
25%6%26%29%13%1
690
11th to 20thNight
26%9%23%30%12%1
746
21st to endNight
29%7%25%27%10%1
990
November1st to 10thNight
24%7%28%25%14%1
925
11th to 20thNight
21%7%31%29%9%3
950
21st to endNight
21%7%32%32%7%1
950
December1st to 10thNight
14%426%37%16%3
950
11th to 20thNight
17%5%31%35%11%2
950
21st to endNight
16%427%33%17%3
1045
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