Wilcox Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wilcox Park clear sky chart from 2005-11-06 to 2024-03-28.

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
27%
23252
17%
80856
8%
23164
38%
23164
18%
53370

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
13%
753
20%
4350
5%
737
30%
737
10%
2522
January11th to 20thNight
15%
759
16%
4356
5%
740
27%
740
7%
2911
January21st to endNight
15%
831
11%
4710
6%
814
30%
814
8%
3330
February1st to 10thNight
16%
760
15%
2470
4%
760
31%
760
14%
1704
February11th to 20thNight
11%
742
16%
2220
3%
740
27%
740
14%
1563
February21st to endNight
13%
628
19%
1884
6%
628
30%
628
15%
1307
March1st to 10thNight
15%
760
18%
2280
7%
760
31%
760
16%
1561
March11th to 20thNight
14%
760
18%
2201
5%
760
28%
760
16%
1522
March21st to endNight
18%
821
20%
2056
5%
821
29%
821
18%
1442
April1st to 10thNight
18%
720
16%
1800
3%
720
26%
720
17%
1335
April11th to 20thNight
22%
711
16%
1775
3%
711
28%
711
21%
1254
April21st to endNight
20%
653
18%
1733
4%
653
29%
653
21%
1209
May1st to 10thNight
21%
540
14%
1620
5%
540
29%
540
16%
1169
May11th to 20thNight
26%
364
19%
1426
11%
364
40%
364
17%
894
May21st to endNight
38%
388
14%
1551
13%
388
46%
388
19%
945
June1st to 10thNight
37%
360
17%
1440
14%
360
50%
360
18%
890
June11th to 20thNight
35%
360
13%
1440
12%
360
44%
360
19%
884
June21st to endNight
47%
360
15%
1440
14%
360
55%
360
25%
816
July1st to 10thNight
52%
350
15%
1400
20%
350
58%
350
25%
791
July11th to 20thNight
50%
348
14%
1392
17%
348
54%
348
23%
820
July21st to endNight
52%
394
18%
1486
18%
372
59%
372
25%
853
August1st to 10thNight
54%
390
18%
1454
15%
388
60%
388
28%
827
August11th to 20thNight
52%
710
16%
1774
10%
710
54%
710
29%
1221
August21st to endNight
47%
792
19%
1980
9%
792
51%
792
33%
1307
September1st to 10thNight
40%
720
20%
1800
8%
720
46%
720
31%
1191
September11th to 20thNight
44%
720
27%
1886
15%
720
51%
720
38%
1133
September21st to endNight
40%
720
25%
1980
16%
720
48%
720
30%
1272
October1st to 10thNight
34%
720
18%
2065
11%
720
41%
720
23%
1396
October11th to 20thNight
31%
720
20%
2160
11%
720
42%
720
25%
1381
October21st to endNight
22%
792
16%
2556
8%
792
34%
792
17%
1764
November1st to 10thNight
28%
740
22%
2407
11%
740
44%
740
22%
1491
November11th to 20thNight
23%
760
21%
2470
10%
760
37%
760
19%
1620
November21st to endNight
23%
760
19%
2574
7%
760
38%
760
19%
1640
December1st to 10thNight
16%
760
16%
2660
5%
760
29%
760
13%
1841
December11th to 20thNight
19%
760
13%
3231
4%
759
31%
759
11%
2213
December21st to endNight
14%
826
11%
4829
4%
817
29%
817
8%
3351

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
17%7%36%5%35%5%5%7%37%
78645
Night
18%8%36%5%3445%6%37%
81339
TransparencyDay
46%5%12%23%13%2
78350
Night
47%5%12%22%13%2
81168
SeeingDay
23%15%30%20%9%2
14035
Night
22%14%32%24%8%1
23277

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
14%9%35%5%35%45%6%40%
2517
11th to 20thDay
16%9%5%9%7%35%46%431%
2520
21st to endDay
21%12%46%6%35%445%29%
2904
February1st to 10thDay
17%10%47%6%36%5%6%5%32%
1710
11th to 20thDay
14%9%46%7%445%46%37%
1846
21st to endDay
20%9%36%6%34446%35%
1570
March1st to 10thDay
15%8%5%7%6%345%46%37%
1897
11th to 20thDay
15%9%46%5%35%45%6%36%
1976
21st to endDay
19%10%35%5%34445%38%
2455
April1st to 10thDay
19%9%36%5%3445%5%37%
2160
11th to 20thDay
16%7%26%6%34447%40%
2134
21st to endDay
22%6%345%44446%37%
2226
May1st to 10thDay
22%8%36%6%3445%5%34%
2345
11th to 20thDay
19%5%25%5%3446%7%40%
2478
21st to endDay
14%6%25%5%345%5%9%40%
2725
June1st to 10thDay
17%6%25%5%46%6%6%10%34%
2520
11th to 20thDay
17%6%25%436%5%7%10%34%
2520
21st to endDay
14%7%26%7%35%5%6%9%36%
2520
July1st to 10thDay
12%5%26%6%46%5%6%8%41%
2520
11th to 20thDay
11%5%25%5%35%5%7%11%40%
2520
21st to endDay
11%6%36%6%36%6%6%9%38%
2744
August1st to 10thDay
11%426%5%36%7%7%9%39%
2454
11th to 20thDay
12%6%26%5%35%6%7%10%37%
2126
21st to endDay
14%5%245%445%6%8%43%
2376
September1st to 10thDay
14%6%35%4345%6%7%41%
2160
11th to 20thDay
13%5%25%4245%5%6%49%
2072
21st to endDay
16%5%244345%7%8%42%
1980
October1st to 10thDay
21%7%25%433446%40%
1890
11th to 20thDay
16%7%26%5%345%5%7%42%
1800
21st to endDay
24%8%345%345%46%33%
1800
November1st to 10thDay
14%7%35%423447%47%
1671
11th to 20thDay
18%7%35%5%35%45%6%39%
1710
21st to endDay
18%7%345%35%5%47%38%
1601
December1st to 10thDay
19%10%47%6%46%5%5%5%30%
1520
11th to 20thDay
23%7%35%424447%36%
1906
21st to endDay
22%10%5%9%7%35%446%25%
2772
January1st to 10thNight
17%8%36%5%3435%6%40%
4429
11th to 20thNight
15%10%48%8%45%5%46%31%
4440
21st to endNight
26%11%37%5%3435%5%28%
4747
February1st to 10thNight
16%10%46%5%36%5%5%6%34%
2470
11th to 20thNight
15%10%47%6%35%5%5%6%33%
2218
21st to endNight
19%9%36%6%3445%5%36%
1884
March1st to 10thNight
17%8%36%6%35%5%5%6%37%
2270
11th to 20thNight
17%8%47%5%45%5%5%6%36%
2200
21st to endNight
19%7%47%5%33445%39%
2056
April1st to 10thNight
19%10%46%6%345%5%7%31%
1800
11th to 20thNight
19%8%36%435%45%7%37%
1775
21st to endNight
22%8%35%5%2435%7%38%
1733
May1st to 10thNight
22%8%37%6%3445%5%32%
1620
11th to 20thNight
18%6%46%5%4445%7%39%
1425
21st to endNight
16%5%36%5%345%6%7%41%
1550
June1st to 10thNight
17%6%35%4245%7%6%41%
1440
11th to 20thNight
17%6%45%5%25%47%8%38%
1440
21st to endNight
12%5%25%5%35%5%6%10%42%
1440
July1st to 10thNight
14%425%4346%6%8%45%
1440
11th to 20thNight
12%5%25%6%35%5%7%10%39%
1440
21st to endNight
11%6%35%6%35%6%5%8%43%
1574
August1st to 10thNight
9%5%26%5%345%7%9%44%
1464
11th to 20thNight
10%7%27%6%36%6%7%9%36%
1774
21st to endNight
15%5%26%5%25%5%48%44%
1980
September1st to 10thNight
15%6%25%43445%6%45%
1800
11th to 20thNight
13%5%24433347%53%
1886
21st to endNight
15%6%2443445%6%46%
1980
October1st to 10thNight
21%6%35%5%24345%41%
2065
11th to 20thNight
16%6%36%5%34447%42%
2160
21st to endNight
23%8%35%5%34446%35%
2556
November1st to 10thNight
15%8%244245%47%45%
2407
11th to 20thNight
19%8%35%434446%40%
2470
21st to endNight
15%8%35%5%35%45%7%40%
2574
December1st to 10thNight
21%9%36%43445%6%33%
2660
11th to 20thNight
21%9%47%5%35%5%5%5%33%
3288
21st to endNight
23%12%46%5%34446%28%
4884

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
44%412%31%8%1
2518
11th to 20thDay
53%6%10%23%7%1
2520
21st to endDay
59%49%20%8%1
2904
February1st to 10thDay
53%412%19%11%1
1710
11th to 20thDay
49%5%8%23%13%2
1855
21st to endDay
52%311%21%12%2
1570
March1st to 10thDay
48%413%20%12%3
1900
11th to 20thDay
48%5%9%23%13%2
1976
21st to endDay
50%47%17%17%5%
2455
April1st to 10thDay
50%5%8%21%14%3
2160
11th to 20thDay
44%410%23%17%2
2134
21st to endDay
49%49%21%14%4
2226
May1st to 10thDay
53%5%8%19%13%2
2345
11th to 20thDay
43%5%10%23%17%2
2482
21st to endDay
41%7%15%23%12%2
2725
June1st to 10thDay
45%6%14%22%12%1
2520
11th to 20thDay
44%5%13%24%11%1
2520
21st to endDay
44%6%12%25%12%1
2520
July1st to 10thDay
41%6%14%22%16%1
2450
11th to 20thDay
38%5%15%28%13%1
2445
21st to endDay
41%5%14%22%15%2
2591
August1st to 10thDay
39%7%14%27%12%1
2440
11th to 20thDay
40%6%17%26%10%1
2126
21st to endDay
38%5%12%27%17%1
2376
September1st to 10thDay
41%5%12%24%15%2
2160
11th to 20thDay
35%410%26%23%2
2072
21st to endDay
40%5%11%24%17%2
1980
October1st to 10thDay
47%410%24%14%2
1890
11th to 20thDay
42%5%13%26%13%2
1800
21st to endDay
53%5%10%19%12%2
1800
November1st to 10thDay
39%414%26%15%3
1671
11th to 20thDay
45%5%10%22%17%2
1710
21st to endDay
46%413%25%10%2
1601
December1st to 10thDay
56%313%17%11%1
1520
11th to 20thDay
48%5%16%21%9%1
1906
21st to endDay
59%6%9%18%8%
2772
January1st to 10thNight
46%314%25%10%2
4429
11th to 20thNight
52%6%11%20%9%2
4440
21st to endNight
58%39%19%9%1
4747
February1st to 10thNight
51%413%20%10%2
2470
11th to 20thNight
50%5%10%16%16%2
2220
21st to endNight
50%39%21%12%4
1884
March1st to 10thNight
47%5%11%22%13%2
2280
11th to 20thNight
49%410%21%13%2
2201
21st to endNight
48%39%18%19%3
2056
April1st to 10thNight
52%49%19%13%2
1800
11th to 20thNight
47%5%10%20%18%1
1775
21st to endNight
48%49%22%14%3
1733
May1st to 10thNight
54%310%17%13%3
1620
11th to 20thNight
46%49%22%16%3
1426
21st to endNight
42%6%17%21%13%1
1551
June1st to 10thNight
43%6%11%26%13%2
1440
11th to 20thNight
42%6%16%25%10%
1440
21st to endNight
37%5%16%28%14%
1440
July1st to 10thNight
36%6%15%26%15%2
1400
11th to 20thNight
39%6%16%28%10%
1392
21st to endNight
37%6%16%24%15%3
1486
August1st to 10thNight
34%7%18%27%14%1
1454
11th to 20thNight
42%6%16%26%10%
1774
21st to endNight
38%5%12%26%18%1
1980
September1st to 10thNight
40%412%27%15%1
1800
11th to 20thNight
32%311%27%25%1
1886
21st to endNight
39%5%9%25%21%1
1980
October1st to 10thNight
47%311%23%14%2
2065
11th to 20thNight
42%414%26%13%1
2160
21st to endNight
51%411%21%12%1
2556
November1st to 10thNight
40%5%10%23%19%3
2407
11th to 20thNight
46%411%21%15%3
2470
21st to endNight
44%415%27%9%1
2574
December1st to 10thNight
52%5%12%20%10%1
2660
11th to 20thNight
52%6%13%16%12%2
3288
21st to endNight
57%411%19%9%
4884

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
27%27%27%12%7%
180
11th to 20thDay
32%25%28%12%3
180
21st to endDay
24%30%32%9%41
236
February1st to 10thDay
34%27%30%7%1
270
11th to 20thDay
29%28%31%12%1
454
21st to endDay
31%21%34%11%3
382
March1st to 10thDay
28%21%32%17%2
460
11th to 20thDay
29%24%32%11%31
460
21st to endDay
34%19%29%11%6%1
490
April1st to 10thDay
31%22%27%12%7%
420
11th to 20thDay
26%26%26%14%6%1
412
21st to endDay
30%17%33%14%5%2
420
May1st to 10thDay
33%15%28%15%7%2
423
11th to 20thDay
25%14%36%18%5%2
447
21st to endDay
21%11%28%27%12%2
485
June1st to 10thDay
21%10%34%22%12%1
450
11th to 20thDay
18%12%29%29%9%2
450
21st to endDay
18%9%32%24%13%3
450
July1st to 10thDay
14%7%32%29%15%4
445
11th to 20thDay
14%5%29%32%18%2
444
21st to endDay
13%7%35%31%13%2
488
August1st to 10thDay
15%430%35%11%5%
446
11th to 20thDay
17%328%27%17%7%
439
21st to endDay
14%8%28%28%15%7%
495
September1st to 10thDay
21%8%22%28%15%6%
450
11th to 20thDay
17%9%29%20%14%10%
450
21st to endDay
20%10%33%22%10%4
450
October1st to 10thDay
27%10%24%21%14%4
450
11th to 20thDay
20%13%35%22%7%1
450
21st to endDay
28%15%29%22%6%1
405
November1st to 10thDay
20%17%29%22%10%2
365
11th to 20thDay
26%22%25%19%6%1
370
21st to endDay
24%22%30%20%31
261
December1st to 10thDay
24%27%31%13%4
180
11th to 20thDay
33%24%30%11%2
180
21st to endDay
30%22%30%13%5%
198
January1st to 10thNight
22%20%39%17%2
760
11th to 20thNight
26%21%33%17%3
760
21st to endNight
21%21%37%19%2
836
February1st to 10thNight
23%19%35%21%1
760
11th to 20thNight
23%23%38%15%1
743
21st to endNight
29%19%35%16%2
628
March1st to 10thNight
24%23%34%16%3
760
11th to 20thNight
25%22%36%14%4
760
21st to endNight
24%23%30%18%4
821
April1st to 10thNight
26%20%32%19%3
720
11th to 20thNight
24%18%33%18%6%
711
21st to endNight
26%15%35%19%41
653
May1st to 10thNight
26%16%31%21%6%
540
11th to 20thNight
20%12%37%27%41
364
21st to endNight
19%7%29%33%12%1
389
June1st to 10thNight
19%7%30%32%12%
360
11th to 20thNight
17%7%32%31%12%1
360
21st to endNight
14%429%41%12%1
360
July1st to 10thNight
15%322%41%19%1
350
11th to 20thNight
16%322%42%16%1
348
21st to endNight
13%324%44%14%1
394
August1st to 10thNight
11%225%42%18%2
390
11th to 20thNight
14%319%41%20%2
710
21st to endNight
16%324%36%19%2
792
September1st to 10thNight
18%429%32%14%2
720
11th to 20thNight
17%5%29%27%19%4
720
21st to endNight
20%7%26%32%13%2
720
October1st to 10thNight
25%8%26%29%11%1
720
11th to 20thNight
20%11%32%28%8%
720
21st to endNight
28%13%31%22%6%
792
November1st to 10thNight
21%13%33%24%8%
740
11th to 20thNight
24%15%33%21%5%1
760
21st to endNight
19%18%35%21%6%1
760
December1st to 10thNight
28%19%31%18%5%
760
11th to 20thNight
25%19%31%21%3
760
21st to endNight
27%16%38%16%2
836
Page generated at 2024-03-24 23:37:02. Version ac07

Copyright © 2024 Attilla Danko.


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