County Road 2C
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the County Road 2C clear sky chart from 2005-11-06 to 2024-03-06.

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
51%
24698
27%
79924
18%
24612
60%
24612
38%
42373

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
51%
938
32%
4314
20%
926
60%
926
32%
2022
January11th to 20thNight
44%
944
32%
4300
19%
930
55%
930
34%
1838
January21st to endNight
49%
864
23%
4305
20%
854
62%
854
28%
2019
February1st to 10thNight
42%
760
27%
2353
16%
760
54%
760
37%
1314
February11th to 20thNight
40%
744
26%
2218
15%
740
50%
740
36%
1269
February21st to endNight
38%
628
34%
1884
15%
628
56%
628
44%
982
March1st to 10thNight
44%
742
29%
2226
15%
742
55%
742
41%
1182
March11th to 20thNight
48%
712
26%
2108
18%
712
54%
712
41%
1147
March21st to endNight
36%
594
27%
1980
12%
594
53%
594
32%
1085
April1st to 10thNight
33%
540
24%
1800
12%
540
49%
540
33%
964
April11th to 20thNight
33%
533
22%
1777
11%
533
49%
533
31%
1002
April21st to endNight
39%
540
22%
1795
17%
540
50%
540
27%
1038
May1st to 10thNight
41%
540
22%
1620
14%
540
51%
540
30%
983
May11th to 20thNight
44%
531
14%
1588
11%
531
49%
531
28%
1011
May21st to endNight
37%
582
17%
1552
8%
582
46%
582
32%
985
June1st to 10thNight
56%
540
20%
1440
12%
540
63%
540
41%
825
June11th to 20thNight
49%
540
25%
1440
12%
540
57%
540
45%
795
June21st to endNight
56%
540
22%
1440
15%
540
61%
540
41%
857
July1st to 10thNight
61%
525
17%
1400
13%
525
64%
525
34%
891
July11th to 20thNight
75%
522
26%
1392
21%
522
77%
522
43%
813
July21st to endNight
65%
591
18%
1488
15%
558
66%
558
31%
965
August1st to 10thNight
64%
537
15%
1678
16%
534
66%
534
28%
1047
August11th to 20thNight
68%
534
23%
1778
25%
534
72%
534
35%
973
August21st to endNight
72%
594
25%
1980
28%
594
76%
594
40%
1016
September1st to 10thNight
63%
540
28%
1800
27%
540
70%
540
38%
951
September11th to 20thNight
66%
540
33%
1894
33%
540
73%
540
45%
886
September21st to endNight
61%
540
33%
1980
30%
540
70%
540
43%
906
October1st to 10thNight
50%
572
31%
2012
23%
572
60%
572
35%
1029
October11th to 20thNight
57%
720
36%
2160
20%
720
69%
720
54%
1011
October21st to endNight
54%
912
34%
2496
17%
912
63%
912
48%
1326
November1st to 10thNight
61%
925
34%
2405
19%
925
67%
925
58%
1223
November11th to 20thNight
53%
950
38%
2470
19%
950
63%
950
55%
1291
November21st to endNight
53%
950
33%
2470
18%
950
61%
950
48%
1356
December1st to 10thNight
50%
950
29%
2585
16%
950
58%
950
45%
1421
December11th to 20thNight
50%
948
30%
3087
18%
948
58%
948
38%
1613
December21st to endNight
44%
1036
20%
4709
16%
1026
55%
1026
27%
2337

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
5%42442445%8%58%
78599
Night
5%5%2443445%8%56%
80971
TransparencyDay
24%5%11%25%24%10%
78303
Night
26%6%11%24%24%9%
80789
SeeingDay
7%7%25%31%22%7%
14561
Night
7%6%30%40%16%1
24741

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
25%26%43335%6%60%
2538
11th to 20thDay
2425%435%5%6%7%57%
2540
21st to endDay
36%2442345%6%61%
3096
February1st to 10thDay
38%25%42345%7%57%
1824
11th to 20thDay
26%35%5%34447%58%
1849
21st to endDay
36%27%5%24435%59%
1570
March1st to 10thDay
44244245%5%7%59%
1850
11th to 20thDay
6%6%33424347%60%
1849
21st to endDay
6%5%25%43445%8%53%
2376
April1st to 10thDay
6%4243245%5%8%57%
2160
11th to 20thDay
8%5%244345%5%8%51%
2131
21st to endDay
8%4245%25%5%6%9%50%
2164
May1st to 10thDay
10%5%244345%6%8%48%
2340
11th to 20thDay
9%5%25%5%35%5%6%9%48%
2304
21st to endDay
7%3234346%6%9%54%
2724
June1st to 10thDay
6%2133235%6%12%56%
2520
11th to 20thDay
5%3133235%5%9%60%
2520
21st to endDay
33144346%6%9%57%
2520
July1st to 10thDay
5%3245%35%6%8%10%51%
2520
11th to 20thDay
22233245%8%9%59%
2520
21st to endDay
5%324435%7%7%12%49%
2742
August1st to 10thDay
4313426%6%8%11%50%
2247
11th to 20thDay
5%4233245%6%10%56%
2123
21st to endDay
431342346%8%62%
2376
September1st to 10thDay
441443446%6%61%
2160
11th to 20thDay
6%213323446%66%
2066
21st to endDay
6%313322435%68%
1980
October1st to 10thDay
8%413223337%63%
1944
11th to 20thDay
4323222346%70%
1800
21st to endDay
6%5%23222335%67%
1841
November1st to 10thDay
331322335%7%68%
1673
11th to 20thDay
2423323335%69%
1710
21st to endDay
45%23323446%65%
1710
December1st to 10thDay
46%25%4235%5%6%59%
1592
11th to 20thDay
35%25%42337%7%59%
1926
21st to endDay
47%26%5%2445%7%54%
2794
January1st to 10thNight
36%245%345%6%7%56%
4417
11th to 20thNight
24234345%6%8%60%
4430
21st to endNight
35%35%5%3345%7%59%
4587
February1st to 10thNight
5%6%35%5%24446%56%
2353
11th to 20thNight
36%36%5%35%5%5%8%51%
2218
21st to endNight
45%34423346%62%
1884
March1st to 10thNight
46%34424446%59%
2226
11th to 20thNight
7%5%2432345%7%58%
2108
21st to endNight
7%6%34425%46%7%53%
1980
April1st to 10thNight
7%6%3433446%7%54%
1800
11th to 20thNight
9%5%25%3346%6%8%48%
1777
21st to endNight
10%6%35%5%3435%9%48%
1795
May1st to 10thNight
11%5%2443446%8%49%
1620
11th to 20thNight
12%7%25%4445%6%7%45%
1588
21st to endNight
13%5%15%4245%6%9%47%
1552
June1st to 10thNight
4323436%6%7%11%53%
1440
11th to 20thNight
44134335%6%11%56%
1440
21st to endNight
5%425%5%35%7%6%10%49%
1440
July1st to 10thNight
6%5%25%5%46%6%8%10%43%
1440
11th to 20thNight
4323437%6%6%10%53%
1440
21st to endNight
7%5%35%5%35%6%7%10%43%
1576
August1st to 10thNight
7%5%35%5%37%7%8%10%41%
1686
11th to 20thNight
6%4245%35%6%7%10%48%
1778
21st to endNight
4324435%6%7%11%53%
1980
September1st to 10thNight
8%4134246%6%7%55%
1800
11th to 20thNight
6%31222347%9%60%
1894
21st to endNight
6%313423346%65%
1980
October1st to 10thNight
9%5%13323447%58%
2012
11th to 20thNight
4212323346%70%
2160
21st to endNight
6%424323335%66%
2496
November1st to 10thNight
2312223337%69%
2405
11th to 20thNight
3423322345%69%
2470
21st to endNight
35%25%423346%63%
2470
December1st to 10thNight
25%25%5%245%47%60%
2585
11th to 20thNight
35%35%5%3445%7%58%
3271
21st to endNight
45%35%5%345%6%7%53%
4873

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
24%49%32%23%8%
2539
11th to 20thDay
24%6%13%27%21%9%
2540
21st to endDay
25%312%30%24%5%
3096
February1st to 10thDay
28%410%25%23%10%
1824
11th to 20thDay
27%47%27%25%9%
1859
21st to endDay
29%38%19%24%17%
1570
March1st to 10thDay
22%5%10%24%25%14%
1850
11th to 20thDay
26%39%25%29%7%
1849
21st to endDay
29%6%12%25%22%6%
2376
April1st to 10thDay
25%6%11%24%24%11%
2160
11th to 20thDay
30%5%11%24%20%9%
2134
21st to endDay
30%5%13%23%23%6%
2164
May1st to 10thDay
32%6%11%25%21%5%
2340
11th to 20thDay
33%6%17%26%16%2
2308
21st to endDay
25%8%17%25%17%8%
2724
June1st to 10thDay
20%8%16%29%18%9%
2520
11th to 20thDay
21%6%11%21%24%17%
2520
21st to endDay
20%7%11%24%25%13%
2520
July1st to 10thDay
26%8%11%20%25%10%
2451
11th to 20thDay
17%7%12%27%27%10%
2445
21st to endDay
26%8%18%29%16%4
2590
August1st to 10thDay
24%10%18%27%14%7%
2231
11th to 20thDay
23%5%11%26%25%11%
2123
21st to endDay
20%49%27%28%11%
2376
September1st to 10thDay
22%5%9%23%25%16%
2160
11th to 20thDay
20%49%17%30%20%
2066
21st to endDay
19%36%20%36%15%
1980
October1st to 10thDay
23%49%21%30%12%
1944
11th to 20thDay
17%36%22%34%18%
1800
21st to endDay
22%38%25%27%16%
1841
November1st to 10thDay
17%39%26%28%17%
1673
11th to 20thDay
19%36%29%32%10%
1710
21st to endDay
22%39%19%31%17%
1710
December1st to 10thDay
26%310%26%28%7%
1592
11th to 20thDay
24%310%23%33%8%
1924
21st to endDay
29%5%10%25%24%7%
2794
January1st to 10thNight
26%5%9%32%24%4
4417
11th to 20thNight
21%5%15%24%24%10%
4430
21st to endNight
25%6%10%32%23%4
4587
February1st to 10thNight
29%5%10%24%23%9%
2353
11th to 20thNight
31%410%27%21%6%
2218
21st to endNight
25%37%22%30%13%
1884
March1st to 10thNight
26%310%21%27%14%
2226
11th to 20thNight
26%412%23%25%9%
2108
21st to endNight
30%6%13%24%22%6%
1980
April1st to 10thNight
29%5%10%24%22%11%
1800
11th to 20thNight
31%6%12%23%20%8%
1777
21st to endNight
35%5%12%23%19%5%
1795
May1st to 10thNight
32%9%13%24%18%5%
1620
11th to 20thNight
37%7%17%20%13%4
1589
21st to endNight
33%8%18%20%13%8%
1552
June1st to 10thNight
22%10%23%23%14%6%
1440
11th to 20thNight
22%8%14%23%20%13%
1440
21st to endNight
28%6%11%25%19%10%
1440
July1st to 10thNight
32%10%14%23%17%4
1400
11th to 20thNight
26%7%11%29%20%6%
1392
21st to endNight
35%10%17%23%14%2
1488
August1st to 10thNight
34%10%17%21%10%6%
1678
11th to 20thNight
28%8%14%27%18%6%
1778
21st to endNight
23%8%14%26%20%9%
1980
September1st to 10thNight
26%6%12%20%24%13%
1800
11th to 20thNight
20%6%11%22%25%16%
1894
21st to endNight
22%48%21%34%12%
1980
October1st to 10thNight
26%6%10%19%26%12%
2012
11th to 20thNight
16%49%22%30%19%
2160
21st to endNight
23%49%24%25%17%
2496
November1st to 10thNight
16%411%25%28%16%
2405
11th to 20thNight
19%37%26%33%12%
2470
21st to endNight
24%38%22%29%15%
2470
December1st to 10thNight
24%5%12%26%25%8%
2585
11th to 20thNight
27%38%23%35%5%
3272
21st to endNight
28%6%10%25%25%6%
4873

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
5%5%29%40%16%5%
270
11th to 20thDay
11%7%27%37%16%1
270
21st to endDay
6%9%31%35%15%4
297
February1st to 10thDay
6%11%39%31%10%3
270
11th to 20thDay
6%5%46%30%11%1
270
21st to endDay
5%15%39%30%8%4
225
March1st to 10thDay
49%31%32%22%2
255
11th to 20thDay
10%10%33%29%17%2
281
21st to endDay
13%16%34%24%11%1
462
April1st to 10thDay
9%15%38%23%12%4
420
11th to 20thDay
11%18%34%24%10%2
412
21st to endDay
10%18%31%26%13%2
424
May1st to 10thDay
12%12%28%29%15%3
603
11th to 20thDay
14%7%27%27%21%4
625
21st to endDay
10%11%28%26%20%5%
679
June1st to 10thDay
6%5%21%29%27%12%
630
11th to 20thDay
46%27%35%23%5%
630
21st to endDay
5%5%22%35%26%8%
630
July1st to 10thDay
7%214%32%33%12%
621
11th to 20thDay
3213%32%38%12%
618
21st to endDay
6%19%29%40%14%
684
August1st to 10thDay
6%113%33%33%14%
493
11th to 20thDay
5%119%33%32%10%
437
21st to endDay
3115%40%28%12%
495
September1st to 10thDay
5%218%36%28%11%
450
11th to 20thDay
4318%37%26%13%
356
21st to endDay
11%419%24%27%16%
270
October1st to 10thDay
10%422%24%26%14%
270
11th to 20thDay
6%328%31%22%10%
270
21st to endDay
10%9%28%25%19%8%
297
November1st to 10thDay
5%6%29%34%21%5%
270
11th to 20thDay
47%32%32%21%4
270
21st to endDay
9%8%24%37%17%4
270
December1st to 10thDay
7%5%31%38%15%3
270
11th to 20thDay
6%10%28%34%19%2
270
21st to endDay
7%10%36%33%12%1
297
January1st to 10thNight
6%6%31%40%15%2
950
11th to 20thNight
5%7%37%38%13%1
950
21st to endNight
47%33%45%11%2
876
February1st to 10thNight
7%6%38%40%7%
760
11th to 20thNight
7%6%41%36%10%1
744
21st to endNight
6%7%44%36%7%
628
March1st to 10thNight
8%8%36%39%9%1
742
11th to 20thNight
10%7%32%38%11%1
712
21st to endNight
9%11%40%32%7%
594
April1st to 10thNight
9%11%41%34%5%
540
11th to 20thNight
12%11%41%28%8%
533
21st to endNight
13%15%29%32%11%1
540
May1st to 10thNight
12%8%35%33%11%
540
11th to 20thNight
13%7%30%33%15%1
531
21st to endNight
13%8%36%32%10%1
584
June1st to 10thNight
5%5%29%42%17%1
540
11th to 20thNight
45%37%42%12%
540
21st to endNight
7%426%46%17%1
540
July1st to 10thNight
7%318%45%26%1
525
11th to 20thNight
5%212%49%30%2
522
21st to endNight
8%112%42%35%2
591
August1st to 10thNight
8%114%42%33%2
537
11th to 20thNight
5%218%52%21%1
534
21st to endNight
6%114%49%28%2
594
September1st to 10thNight
9%319%46%21%1
540
11th to 20thNight
7%221%42%26%3
540
21st to endNight
7%324%43%21%2
540
October1st to 10thNight
12%6%28%37%15%2
572
11th to 20thNight
5%6%28%38%20%3
720
21st to endNight
7%8%27%35%19%3
912
November1st to 10thNight
4427%44%19%2
925
11th to 20thNight
5%6%32%39%16%2
950
21st to endNight
7%7%28%39%15%3
950
December1st to 10thNight
46%34%43%12%2
950
11th to 20thNight
6%6%30%41%15%1
950
21st to endNight
7%10%33%39%11%1
1045
Page generated at 2024-03-03 04:28:56. Version ac07

Copyright © 2024 Attilla Danko.


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