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 2024-11-02.

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%
25347
26%
94857
19%
25147
61%
25147
33%
49206

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
54%
825
23%
4247
24%
814
66%
814
29%
1907
February1st to 10thNight
43%
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
40%
628
35%
1884
16%
628
59%
628
45%
970
March1st to 10thNight
46%
753
33%
3618
16%
744
57%
744
31%
1576
March11th to 20thNight
49%
751
23%
3593
17%
740
55%
740
27%
1820
March21st to endNight
38%
639
20%
3389
14%
627
56%
627
24%
1581
April1st to 10thNight
36%
570
27%
1900
14%
570
53%
570
35%
1007
April11th to 20thNight
35%
563
22%
1877
14%
563
49%
563
30%
1046
April21st to endNight
43%
570
20%
1900
17%
570
52%
570
27%
1112
May1st to 10thNight
41%
568
26%
2785
15%
559
52%
559
21%
1475
May11th to 20thNight
47%
549
13%
2640
11%
541
53%
541
19%
1454
May21st to endNight
42%
606
11%
2748
9%
593
50%
593
22%
1466
June1st to 10thNight
57%
570
22%
1520
15%
570
62%
570
39%
890
June11th to 20thNight
55%
570
24%
1520
16%
570
60%
570
47%
822
June21st to endNight
60%
570
21%
1520
17%
570
63%
570
38%
926
July1st to 10thNight
62%
542
21%
2223
16%
535
64%
535
22%
1293
July11th to 20thNight
74%
538
20%
2236
22%
533
76%
533
28%
1186
July21st to endNight
68%
610
17%
2210
17%
569
69%
569
25%
1242
August1st to 10thNight
64%
559
11%
2824
14%
545
66%
545
14%
1903
August11th to 20thNight
68%
550
16%
2970
26%
543
72%
543
18%
1779
August21st to endNight
73%
614
20%
3223
28%
605
77%
605
23%
1663
September1st to 10thNight
69%
570
29%
1900
30%
570
73%
570
37%
1003
September11th to 20thNight
69%
570
33%
1969
33%
570
75%
570
47%
908
September21st to endNight
63%
570
31%
2090
29%
570
70%
570
41%
976
October1st to 10thNight
54%
655
32%
2175
23%
655
62%
655
38%
1113
October11th to 20thNight
60%
760
35%
2280
21%
760
69%
760
51%
1102
October21st to endNight
56%
922
35%
2594
19%
922
65%
922
49%
1341
November1st to 10thNight
61%
935
35%
2431
20%
935
67%
935
58%
1231
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
45%2434446%8%56%
101203
Night
5%5%25%44446%7%55%
97986
TransparencyDay
23%6%11%24%24%12%
100945
Night
26%6%11%23%23%10%
97834
SeeingDay
7%7%26%30%22%8%
15538
Night
7%6%28%40%18%2
25510

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%25%23336%7%61%
2538
11th to 20thDay
1325%34437%8%59%
2575
21st to endDay
26%25%444346%60%
3146
February1st to 10thDay
27%36%33435%7%56%
1780
11th to 20thDay
16%27%443446%59%
1849
21st to endDay
26%27%5%44345%58%
1570
March1st to 10thDay
2424334447%62%
3130
11th to 20thDay
410%35%33235%7%55%
3330
21st to endDay
36%25%44446%8%53%
4129
April1st to 10thDay
5%6%2444336%6%57%
2280
11th to 20thDay
7%8%24445%36%8%49%
2251
21st to endDay
8%5%25%44437%8%50%
2280
May1st to 10thDay
8%6%25%435%45%6%52%
4056
11th to 20thDay
8%5%25%3445%6%9%49%
4171
21st to endDay
6%41433447%10%55%
4825
June1st to 10thDay
6%3143445%9%10%51%
2660
11th to 20thDay
5%31343446%9%57%
2660
21st to endDay
3325%45%5%5%8%9%52%
2660
July1st to 10thDay
4325%446%5%8%10%50%
4430
11th to 20thDay
3215%5%5%6%5%8%9%50%
4430
21st to endDay
4324445%47%8%54%
4778
August1st to 10thDay
9%424445%5%9%12%42%
3939
11th to 20thDay
4314445%5%7%10%52%
3726
21st to endDay
3324445%5%8%10%52%
4180
September1st to 10thDay
431433437%8%58%
2280
11th to 20thDay
6%31323346%6%64%
2210
21st to endDay
6%313233247%68%
2090
October1st to 10thDay
7%41322235%6%63%
2002
11th to 20thDay
3424332246%68%
1900
21st to endDay
5%5%23223235%68%
1982
November1st to 10thDay
231333326%6%67%
1682
11th to 20thDay
242432335%5%67%
1710
21st to endDay
25%25%32325%7%65%
1710
December1st to 10thDay
27%25%35%4348%59%
1544
11th to 20thDay
26%25%43435%7%57%
1926
21st to endDay
37%37%43435%7%56%
2794
January1st to 10thNight
27%26%44445%8%55%
4417
11th to 20thNight
1425%33446%7%62%
4426
21st to endNight
25%25%34435%7%60%
4521
February1st to 10thNight
36%35%43435%6%58%
2399
11th to 20thNight
38%37%34436%6%54%
2218
21st to endNight
36%25%23435%6%62%
1884
March1st to 10thNight
26%25%33435%6%61%
3734
11th to 20thNight
7%8%26%433345%54%
3630
21st to endNight
46%25%44345%8%54%
3512
April1st to 10thNight
5%6%25%33345%7%56%
1900
11th to 20thNight
9%7%25%43345%8%49%
1877
21st to endNight
11%7%3444445%7%47%
1900
May1st to 10thNight
9%7%26%33445%7%50%
2914
11th to 20thNight
8%8%26%5%4446%7%46%
2719
21st to endNight
9%6%2445%5%46%7%48%
2762
June1st to 10thNight
5%315%5%5%35%8%8%52%
1520
11th to 20thNight
4323335%46%9%58%
1520
21st to endNight
5%6%15%5%45%5%7%10%48%
1520
July1st to 10thNight
6%426%45%5%5%8%9%46%
2540
11th to 20thNight
33145%5%7%6%9%11%46%
2540
21st to endNight
5%42444447%8%53%
2782
August1st to 10thNight
11%6%29%6%6%6%5%7%7%34%
2997
11th to 20thNight
6%5%28%5%5%6%5%8%9%42%
3113
21st to endNight
3325%5%5%6%6%10%12%44%
3487
September1st to 10thNight
6%426%44345%9%54%
1900
11th to 20thNight
6%31343446%8%60%
1969
21st to endNight
6%414323246%64%
2090
October1st to 10thNight
8%314333346%61%
2175
11th to 20thNight
341322335%6%66%
2280
21st to endNight
5%423232346%66%
2594
November1st to 10thNight
2423223247%68%
2431
11th to 20thNight
25%23223245%69%
2470
21st to endNight
35%25%332346%63%
2470
December1st to 10thNight
16%17%33335%7%60%
2631
11th to 20thNight
26%25%43446%7%57%
3271
21st to endNight
36%26%445%35%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
19%48%21%29%19%
3130
11th to 20thDay
27%6%9%30%24%4
3330
21st to endDay
25%6%11%31%22%5%
4129
April1st to 10thDay
25%5%11%24%22%13%
2280
11th to 20thDay
30%6%10%24%19%12%
2254
21st to endDay
28%6%13%26%22%6%
2280
May1st to 10thDay
27%5%11%23%18%14%
4056
11th to 20thDay
27%8%15%23%21%6%
4175
21st to endDay
20%7%14%24%22%12%
4825
June1st to 10thDay
22%8%15%27%18%10%
2660
11th to 20thDay
21%5%11%18%25%19%
2660
21st to endDay
23%8%10%22%24%13%
2660
July1st to 10thDay
23%7%12%16%27%14%
4361
11th to 20thDay
21%9%14%23%24%9%
4355
21st to endDay
23%7%12%20%20%18%
4627
August1st to 10thDay
29%10%17%27%12%5%
3925
11th to 20thDay
22%8%15%21%24%11%
3762
21st to endDay
22%7%12%25%25%11%
4179
September1st to 10thDay
21%5%9%24%25%16%
2280
11th to 20thDay
19%48%17%30%21%
2210
21st to endDay
18%46%19%36%17%
2090
October1st to 10thDay
22%49%19%31%15%
2002
11th to 20thDay
17%39%20%34%17%
1900
21st to endDay
22%36%24%28%17%
1982
November1st to 10thDay
16%39%25%28%19%
1682
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
23%5%8%18%30%17%
3734
11th to 20thNight
31%5%14%21%22%7%
3630
21st to endNight
26%7%14%27%22%4
3512
April1st to 10thNight
26%6%9%24%22%12%
1900
11th to 20thNight
32%5%12%23%18%10%
1877
21st to endNight
35%6%12%23%18%6%
1900
May1st to 10thNight
30%9%12%23%16%10%
2914
11th to 20thNight
34%8%14%25%10%8%
2720
21st to endNight
31%10%13%22%18%7%
2762
June1st to 10thNight
24%10%19%23%15%9%
1520
11th to 20thNight
21%7%16%21%19%16%
1520
21st to endNight
30%8%10%22%20%11%
1520
July1st to 10thNight
33%7%10%21%23%5%
2500
11th to 20thNight
25%9%18%24%19%5%
2492
21st to endNight
26%8%13%19%22%12%
2695
August1st to 10thNight
46%8%15%18%8%6%
2988
11th to 20thNight
36%10%13%19%18%4
3143
21st to endNight
27%10%15%26%17%5%
3487
September1st to 10thNight
26%6%11%21%23%12%
1900
11th to 20thNight
19%5%11%22%26%16%
1969
21st to endNight
22%48%19%32%14%
2090
October1st to 10thNight
25%6%9%20%28%13%
2175
11th to 20thNight
18%48%23%29%18%
2280
21st to endNight
22%49%23%27%16%
2594
November1st to 10thNight
17%39%25%28%18%
2431
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
38%35%35%17%2
270
11th to 20thDay
10%12%30%32%12%4
365
21st to endDay
9%18%40%22%8%2
506
April1st to 10thDay
10%15%36%27%10%3
460
11th to 20thDay
10%19%40%21%9%2
452
21st to endDay
12%13%32%29%11%2
460
May1st to 10thDay
13%10%33%28%11%4
615
11th to 20thDay
13%7%27%28%20%6%
675
21st to endDay
9%8%31%27%19%7%
734
June1st to 10thDay
6%5%22%30%28%10%
680
11th to 20thDay
5%5%26%31%26%6%
680
21st to endDay
4421%35%27%9%
680
July1st to 10thDay
5%315%28%38%11%
671
11th to 20thDay
4110%32%38%15%
668
21st to endDay
6%111%27%39%17%
727
August1st to 10thDay
6%216%33%29%15%
487
11th to 20thDay
3316%34%31%12%
477
21st to endDay
4116%36%30%13%
539
September1st to 10thDay
4119%36%27%12%
490
11th to 20thDay
5%125%33%24%11%
420
21st to endDay
9%319%25%27%16%
300
October1st to 10thDay
9%419%24%28%15%
300
11th to 20thDay
45%28%32%22%10%
300
21st to endDay
9%9%25%26%22%7%
330
November1st to 10thDay
35%35%32%19%7%
273
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%8%36%38%11%1
760
11th to 20thNight
8%7%31%39%13%1
760
21st to endNight
8%9%40%33%9%
649
April1st to 10thNight
7%11%42%32%8%
570
11th to 20thNight
12%12%35%32%8%
563
21st to endNight
13%13%26%35%12%
570
May1st to 10thNight
12%9%33%34%11%1
570
11th to 20thNight
13%7%26%36%17%1
561
21st to endNight
11%8%35%32%15%1
617
June1st to 10thNight
5%6%24%44%19%1
570
11th to 20thNight
5%431%46%14%1
570
21st to endNight
6%5%21%45%23%1
570
July1st to 10thNight
7%316%42%30%3
555
11th to 20thNight
5%110%45%37%3
552
21st to endNight
8%110%37%40%4
624
August1st to 10thNight
8%312%41%34%2
567
11th to 20thNight
6%214%47%29%2
564
21st to endNight
6%111%44%34%3
627
September1st to 10thNight
6%314%44%29%3
570
11th to 20thNight
6%316%45%27%3
570
21st to endNight
9%321%41%24%2
570
October1st to 10thNight
10%6%24%36%21%3
655
11th to 20thNight
5%6%26%38%21%4
760
21st to endNight
7%8%26%34%21%3
922
November1st to 10thNight
4326%43%21%2
935
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 2024-10-30 11:19:24. Version ac07

Copyright © 2024 Attilla Danko.


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