McCurdy Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the McCurdy Road clear sky chart from 2005-11-06 to 2024-03-08.

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
53%
24705
27%
79947
19%
24614
62%
24614
38%
42350

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%
939
31%
4325
20%
926
61%
926
32%
2062
January11th to 20thNight
45%
943
34%
4284
20%
926
56%
926
35%
1824
January21st to endNight
55%
825
23%
4247
24%
814
66%
814
29%
1907
February1st to 10thNight
44%
760
28%
2399
16%
760
56%
760
39%
1277
February11th to 20thNight
43%
743
26%
2218
17%
740
53%
740
37%
1258
February21st to endNight
41%
628
35%
1884
16%
628
59%
628
45%
970
March1st to 10thNight
46%
750
29%
2250
16%
750
57%
750
42%
1188
March11th to 20thNight
50%
720
26%
2068
17%
720
56%
720
40%
1178
March21st to endNight
39%
615
29%
2001
15%
615
56%
615
35%
1076
April1st to 10thNight
36%
540
26%
1800
13%
540
52%
540
35%
958
April11th to 20thNight
35%
533
22%
1777
13%
533
50%
533
30%
992
April21st to endNight
44%
540
21%
1800
18%
540
53%
540
27%
1051
May1st to 10thNight
43%
540
22%
1656
16%
540
52%
540
30%
1011
May11th to 20thNight
47%
531
15%
1541
11%
531
52%
531
28%
991
May21st to endNight
43%
582
18%
1552
9%
582
51%
582
33%
966
June1st to 10thNight
58%
540
21%
1440
14%
540
63%
540
39%
837
June11th to 20thNight
55%
540
25%
1440
16%
540
61%
540
48%
771
June21st to endNight
61%
540
22%
1440
17%
540
65%
540
40%
865
July1st to 10thNight
64%
525
16%
1400
15%
525
65%
525
31%
915
July11th to 20thNight
75%
522
26%
1392
22%
522
77%
522
40%
810
July21st to endNight
69%
591
18%
1496
17%
558
69%
558
31%
978
August1st to 10thNight
66%
537
14%
1687
14%
534
67%
534
25%
1058
August11th to 20thNight
70%
534
23%
1778
26%
534
72%
534
33%
1005
August21st to endNight
74%
594
24%
1980
28%
594
77%
594
36%
1059
September1st to 10thNight
68%
540
28%
1800
28%
540
73%
540
37%
956
September11th to 20thNight
70%
540
34%
1865
33%
540
77%
540
46%
866
September21st to endNight
62%
540
31%
1980
30%
540
70%
540
41%
928
October1st to 10thNight
52%
620
30%
2060
21%
620
61%
620
37%
1065
October11th to 20thNight
60%
720
36%
2160
21%
720
70%
720
52%
1033
October21st to endNight
56%
873
34%
2457
18%
873
65%
873
48%
1281
November1st to 10thNight
61%
925
35%
2405
20%
925
67%
925
58%
1221
November11th to 20thNight
56%
950
38%
2470
20%
950
65%
950
56%
1275
November21st to endNight
53%
950
33%
2470
18%
950
60%
950
48%
1349
December1st to 10thNight
50%
950
29%
2631
16%
950
58%
950
45%
1432
December11th to 20thNight
51%
948
30%
3085
19%
948
59%
948
37%
1632
December21st to endNight
45%
1037
20%
4709
16%
1026
56%
1026
29%
2305

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%4244345%6%8%56%
78638
Night
45%2442445%7%57%
80990
TransparencyDay
24%6%11%24%24%11%
78343
Night
26%6%11%24%24%10%
80807
SeeingDay
7%7%26%30%22%8%
14547
Night
7%6%28%39%18%2
24743

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%3432346%7%61%
2538
11th to 20thDay
132443446%9%59%
2575
21st to endDay
26%245%34346%60%
3146
February1st to 10thDay
27%35%424447%57%
1780
11th to 20thDay
15%36%5%33446%59%
1849
21st to endDay
26%35%5%25%445%58%
1570
March1st to 10thDay
3424425%5%5%7%58%
1870
11th to 20thDay
5%7%3433235%6%58%
1890
21st to endDay
5%6%345%2445%8%52%
2353
April1st to 10thDay
6%5%2343445%6%58%
2160
11th to 20thDay
8%7%245%35%46%8%49%
2131
21st to endDay
8%5%245%345%7%8%50%
2160
May1st to 10thDay
11%6%245%36%6%5%8%46%
2304
11th to 20thDay
8%6%25%4346%7%10%44%
2352
21st to endDay
7%3243246%7%10%51%
2724
June1st to 10thDay
6%3133346%8%11%52%
2520
11th to 20thDay
5%3134345%6%9%57%
2520
21st to endDay
33245%45%6%7%9%53%
2520
July1st to 10thDay
6%3245%35%7%8%10%48%
2520
11th to 20thDay
4214435%6%8%9%53%
2520
21st to endDay
5%425%5%36%7%9%11%44%
2731
August1st to 10thDay
4324435%7%10%12%44%
2240
11th to 20thDay
5%4244245%6%9%55%
2123
21st to endDay
5%3233235%6%9%58%
2376
September1st to 10thDay
432443447%8%58%
2160
11th to 20thDay
6%31232345%6%63%
2094
21st to endDay
6%312222346%68%
1980
October1st to 10thDay
8%413322447%62%
1897
11th to 20thDay
3313323346%70%
1800
21st to endDay
6%423223335%67%
1878
November1st to 10thDay
231332435%7%67%
1673
11th to 20thDay
242432345%6%67%
1710
21st to endDay
35%15%423347%65%
1710
December1st to 10thDay
27%24344447%59%
1544
11th to 20thDay
26%35%42446%8%57%
1926
21st to endDay
36%36%5%23447%57%
2794
January1st to 10thNight
26%25%5%3445%8%55%
4417
11th to 20thNight
13244245%6%7%62%
4426
21st to endNight
243443445%7%60%
4521
February1st to 10thNight
36%35%42445%7%58%
2399
11th to 20thNight
37%36%42446%7%54%
2218
21st to endNight
36%2432445%6%62%
1884
March1st to 10thNight
35%243345%47%59%
2250
11th to 20thNight
6%6%2442445%5%57%
2068
21st to endNight
6%6%2442445%8%56%
2001
April1st to 10thNight
5%6%3443345%7%57%
1800
11th to 20thNight
9%6%25%43445%9%49%
1777
21st to endNight
11%7%24434447%48%
1800
May1st to 10thNight
11%6%25%4235%6%7%47%
1656
11th to 20thNight
10%8%26%6%35%5%6%7%44%
1541
21st to endNight
10%6%33325%5%5%9%48%
1552
June1st to 10thNight
43144446%8%10%52%
1440
11th to 20thNight
4323325%5%6%9%60%
1440
21st to endNight
5%5%245%346%7%10%49%
1440
July1st to 10thNight
7%435%5%46%7%8%10%43%
1440
11th to 20thNight
43235%45%6%7%8%53%
1440
21st to endNight
7%5%245%36%7%9%11%41%
1584
August1st to 10thNight
7%426%6%46%6%8%9%41%
1696
11th to 20thNight
7%3245%35%5%7%9%49%
1778
21st to endNight
5%3245%35%7%8%10%49%
1980
September1st to 10thNight
6%425%5%345%5%9%54%
1800
11th to 20thNight
6%3134245%6%8%59%
1865
21st to endNight
6%423323346%64%
1980
October1st to 10thNight
9%414333336%60%
2060
11th to 20thNight
331332345%5%68%
2160
21st to endNight
5%423322346%66%
2457
November1st to 10thNight
2423323347%68%
2405
11th to 20thNight
2423223346%69%
2470
21st to endNight
35%24433346%63%
2470
December1st to 10thNight
15%26%42345%7%61%
2631
11th to 20thNight
25%35%42446%7%57%
3271
21st to endNight
35%25%5%3445%7%56%
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
22%38%31%27%8%
2539
11th to 20thDay
21%7%12%28%22%9%
2575
21st to endDay
26%49%28%27%6%
3146
February1st to 10thDay
27%5%12%24%22%11%
1780
11th to 20thDay
27%47%26%28%9%
1859
21st to endDay
28%37%20%24%18%
1570
March1st to 10thDay
24%49%25%24%14%
1870
11th to 20thDay
27%49%24%29%7%
1890
21st to endDay
29%6%11%25%22%8%
2353
April1st to 10thDay
25%5%11%24%22%12%
2160
11th to 20thDay
30%6%10%24%19%11%
2134
21st to endDay
28%6%13%25%22%6%
2160
May1st to 10thDay
33%7%12%23%21%5%
2304
11th to 20thDay
32%9%17%22%17%3
2356
21st to endDay
25%8%16%25%18%9%
2724
June1st to 10thDay
22%8%15%27%18%11%
2520
11th to 20thDay
21%5%11%19%25%18%
2520
21st to endDay
23%7%10%23%25%13%
2520
July1st to 10thDay
26%7%13%19%22%12%
2451
11th to 20thDay
19%8%13%27%24%10%
2445
21st to endDay
28%10%17%25%16%4
2579
August1st to 10thDay
25%12%19%23%13%8%
2225
11th to 20thDay
24%6%10%23%25%12%
2123
21st to endDay
19%6%11%26%27%11%
2376
September1st to 10thDay
22%5%9%24%25%15%
2160
11th to 20thDay
20%49%17%30%20%
2094
21st to endDay
18%46%20%36%16%
1980
October1st to 10thDay
23%49%20%30%13%
1897
11th to 20thDay
16%38%20%35%18%
1800
21st to endDay
22%36%24%27%18%
1878
November1st to 10thDay
16%39%25%28%19%
1673
11th to 20thDay
19%36%29%33%10%
1710
21st to endDay
21%37%20%29%20%
1710
December1st to 10thDay
25%311%25%27%8%
1544
11th to 20thDay
25%48%23%31%10%
1924
21st to endDay
27%5%9%25%24%10%
2794
January1st to 10thNight
26%5%9%29%27%4
4417
11th to 20thNight
20%6%11%28%25%10%
4426
21st to endNight
23%6%11%31%25%4
4521
February1st to 10thNight
27%5%9%25%24%10%
2399
11th to 20thNight
29%5%10%25%22%8%
2218
21st to endNight
22%5%6%24%28%16%
1884
March1st to 10thNight
25%49%22%27%13%
2250
11th to 20thNight
28%5%11%22%26%8%
2068
21st to endNight
28%5%12%23%26%6%
2001
April1st to 10thNight
27%6%9%24%22%12%
1800
11th to 20thNight
32%5%12%24%18%9%
1777
21st to endNight
35%6%12%22%19%6%
1800
May1st to 10thNight
33%8%12%24%17%6%
1656
11th to 20thNight
37%9%17%20%13%5%
1542
21st to endNight
33%8%17%19%15%9%
1552
June1st to 10thNight
23%10%19%23%15%9%
1440
11th to 20thNight
20%7%16%22%19%16%
1440
21st to endNight
28%8%10%22%20%12%
1440
July1st to 10thNight
37%8%13%19%18%5%
1400
11th to 20thNight
25%9%11%30%19%6%
1392
21st to endNight
33%11%19%20%15%1
1496
August1st to 10thNight
36%10%16%20%10%7%
1687
11th to 20thNight
29%8%11%26%19%5%
1778
21st to endNight
25%9%13%25%19%9%
1980
September1st to 10thNight
27%6%12%21%23%12%
1800
11th to 20thNight
20%5%11%22%26%16%
1865
21st to endNight
23%48%20%32%14%
1980
October1st to 10thNight
26%6%9%20%27%12%
2060
11th to 20thNight
17%47%22%29%19%
2160
21st to endNight
22%49%23%26%16%
2457
November1st to 10thNight
17%39%25%28%18%
2405
11th to 20thNight
18%38%25%33%12%
2470
21st to endNight
24%38%21%30%14%
2470
December1st to 10thNight
24%411%26%24%10%
2631
11th to 20thNight
25%5%7%20%35%7%
3272
21st to endNight
27%6%12%21%26%9%
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
6%6%27%37%18%5%
270
11th to 20thDay
8%9%31%35%14%2
270
21st to endDay
49%30%34%18%4
297
February1st to 10thDay
5%7%43%31%10%4
270
11th to 20thDay
29%42%33%13%1
270
21st to endDay
411%46%28%8%2
225
March1st to 10thDay
28%34%37%17%2
261
11th to 20thDay
10%11%32%33%11%3
330
21st to endDay
10%19%40%22%8%2
462
April1st to 10thDay
10%15%35%27%10%3
420
11th to 20thDay
10%18%40%20%8%2
412
21st to endDay
13%14%32%27%11%2
420
May1st to 10thDay
13%10%32%28%12%4
567
11th to 20thDay
13%7%27%27%20%6%
625
21st to endDay
9%8%31%26%19%7%
679
June1st to 10thDay
6%5%22%28%28%10%
630
11th to 20thDay
5%5%27%32%26%6%
630
21st to endDay
4421%34%28%9%
630
July1st to 10thDay
5%214%27%40%11%
621
11th to 20thDay
4110%32%39%14%
618
21st to endDay
6%110%26%41%17%
673
August1st to 10thDay
5%116%33%30%15%
447
11th to 20thDay
3316%35%30%12%
437
21st to endDay
4115%36%31%13%
495
September1st to 10thDay
4120%37%26%11%
450
11th to 20thDay
4125%33%25%12%
384
21st to endDay
10%319%24%27%17%
270
October1st to 10thDay
10%5%20%24%27%15%
270
11th to 20thDay
45%27%31%23%10%
270
21st to endDay
10%9%25%27%22%8%
297
November1st to 10thDay
35%34%32%19%7%
270
11th to 20thDay
36%29%35%23%4
270
21st to endDay
6%10%24%36%17%6%
270
December1st to 10thDay
410%36%31%16%3
270
11th to 20thDay
7%7%29%32%22%3
270
21st to endDay
5%12%34%38%10%1
297
January1st to 10thNight
5%5%33%40%15%3
950
11th to 20thNight
5%7%37%36%12%2
946
21st to endNight
45%29%48%13%2
836
February1st to 10thNight
6%5%41%39%8%1
760
11th to 20thNight
6%6%40%39%9%1
744
21st to endNight
6%7%43%35%7%1
628
March1st to 10thNight
5%9%37%38%11%1
750
11th to 20thNight
8%7%31%40%13%2
720
21st to endNight
9%9%40%33%9%
615
April1st to 10thNight
7%11%42%33%8%
540
11th to 20thNight
12%12%35%32%8%
533
21st to endNight
14%12%26%35%12%
540
May1st to 10thNight
12%8%31%35%12%1
540
11th to 20thNight
14%7%26%34%17%1
531
21st to endNight
11%7%34%31%15%1
584
June1st to 10thNight
5%6%24%43%20%1
540
11th to 20thNight
4432%45%14%1
540
21st to endNight
6%421%45%24%1
540
July1st to 10thNight
7%316%41%31%3
525
11th to 20thNight
5%110%44%37%3
522
21st to endNight
8%19%36%41%4
591
August1st to 10thNight
7%212%42%35%2
537
11th to 20thNight
6%213%47%30%2
534
21st to endNight
6%111%43%36%4
594
September1st to 10thNight
7%315%44%28%3
540
11th to 20thNight
6%315%44%28%3
540
21st to endNight
9%322%41%24%2
540
October1st to 10thNight
10%6%25%35%20%4
620
11th to 20thNight
5%5%26%38%21%4
720
21st to endNight
7%8%26%34%21%3
873
November1st to 10thNight
4326%43%21%2
925
11th to 20thNight
5%5%30%41%16%2
950
21st to endNight
7%7%27%38%16%3
950
December1st to 10thNight
36%34%41%14%2
950
11th to 20thNight
5%6%29%43%15%2
950
21st to endNight
7%8%33%39%11%1
1045
Page generated at 2024-03-05 05:24:03. Version ac07

Copyright © 2024 Attilla Danko.


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