Chaco Culture National Historical Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chaco Culture National Historical Park clear sky chart from 2005-11-06 to 2024-03-18.

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
59%
24377
30%
80032
23%
24279
67%
24279
40%
41191

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
57%
756
28%
4018
27%
736
68%
736
25%
2011
January11th to 20thNight
56%
754
35%
3973
30%
740
64%
740
31%
1614
January21st to endNight
57%
826
23%
4304
28%
814
68%
814
24%
2283
February1st to 10thNight
52%
760
31%
2470
24%
760
63%
760
45%
1210
February11th to 20thNight
49%
741
29%
2331
23%
740
58%
740
37%
1270
February21st to endNight
46%
628
35%
1835
22%
628
60%
628
44%
975
March1st to 10thNight
51%
760
36%
2090
21%
760
62%
760
50%
1085
March11th to 20thNight
53%
752
32%
2068
19%
752
62%
752
44%
1146
March21st to endNight
48%
792
30%
2178
15%
792
61%
792
45%
1170
April1st to 10thNight
45%
557
32%
1817
20%
557
60%
557
44%
878
April11th to 20thNight
43%
533
32%
1777
20%
533
60%
533
39%
873
April21st to endNight
43%
540
33%
1800
21%
540
61%
540
42%
862
May1st to 10thNight
54%
540
30%
1732
22%
540
66%
540
45%
829
May11th to 20thNight
53%
531
26%
1594
17%
531
62%
531
40%
868
May21st to endNight
55%
584
29%
1720
17%
582
67%
582
52%
823
June1st to 10thNight
63%
540
34%
1440
23%
540
69%
540
56%
726
June11th to 20thNight
66%
540
35%
1440
26%
540
70%
540
64%
690
June21st to endNight
69%
540
27%
1508
21%
540
73%
540
48%
808
July1st to 10thNight
70%
525
16%
1575
14%
525
72%
525
33%
941
July11th to 20thNight
71%
522
18%
1566
16%
522
72%
522
31%
943
July21st to endNight
67%
591
14%
1674
13%
558
68%
558
23%
1124
August1st to 10thNight
72%
537
18%
1602
16%
534
73%
534
30%
985
August11th to 20thNight
68%
534
19%
1706
19%
534
69%
534
26%
1073
August21st to endNight
75%
594
26%
1980
28%
594
77%
594
36%
1085
September1st to 10thNight
69%
540
26%
1800
28%
540
72%
540
31%
1042
September11th to 20thNight
72%
567
36%
1827
34%
567
76%
567
44%
935
September21st to endNight
71%
720
34%
2049
26%
720
76%
720
53%
1027
October1st to 10thNight
61%
720
30%
2160
21%
720
67%
720
47%
1109
October11th to 20thNight
71%
720
40%
2160
28%
720
80%
720
61%
972
October21st to endNight
65%
792
41%
2376
28%
792
75%
792
56%
1094
November1st to 10thNight
68%
740
40%
2220
29%
740
76%
740
58%
1010
November11th to 20thNight
69%
823
41%
2343
29%
823
77%
823
62%
1073
November21st to endNight
59%
950
33%
2602
22%
950
65%
950
47%
1383
December1st to 10thNight
59%
950
32%
2660
22%
950
66%
950
48%
1400
December11th to 20thNight
52%
949
29%
3140
21%
948
59%
948
35%
1739
December21st to endNight
48%
929
19%
4497
21%
917
56%
917
26%
2135

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
442443445%7%59%
78835
Night
45%2443445%7%59%
81004
TransparencyDay
24%6%9%20%26%16%
78560
Night
24%5%9%21%26%15%
80800
SeeingDay
6%8%21%28%25%13%
13983
Night
5%5%24%40%23%3
24408

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
27%35%43345%6%58%
2858
11th to 20thDay
24243345%6%7%60%
2860
21st to endDay
5%8%45%5%345%46%50%
3146
February1st to 10thDay
26%36%423347%60%
1710
11th to 20thDay
5%6%35%5%34448%53%
1736
21st to endDay
48%344345%5%7%54%
1617
March1st to 10thDay
46%345%2445%8%55%
2090
11th to 20thDay
36%25%5%25%5%5%8%53%
2058
21st to endDay
46%245%34446%58%
2178
April1st to 10thDay
342442445%7%62%
2142
11th to 20thDay
35%234345%6%6%60%
2131
21st to endDay
432442445%6%62%
2160
May1st to 10thDay
332332435%6%65%
2223
11th to 20thDay
44245%25%46%6%58%
2301
21st to endDay
3314334446%64%
2552
June1st to 10thDay
221332445%7%68%
2520
11th to 20thDay
222322346%75%
2520
21st to endDay
22125%345%6%6%65%
2444
July1st to 10thDay
43145%35%7%6%10%52%
2340
11th to 20thDay
33135%36%6%8%11%50%
2340
21st to endDay
4326%7%47%7%8%12%40%
2545
August1st to 10thDay
4436%6%47%7%8%9%43%
2328
11th to 20thDay
4325%5%35%6%7%9%51%
2192
21st to endDay
5%3244346%7%8%54%
2376
September1st to 10thDay
5%3245%35%5%6%8%54%
2160
11th to 20thDay
43234345%6%6%61%
2128
21st to endDay
5%213323445%69%
1909
October1st to 10thDay
5%41442345%7%61%
1800
11th to 20thDay
431231222476%
1800
21st to endDay
3213323335%73%
1980
November1st to 10thDay
2313312225%75%
1859
11th to 20thDay
2223223345%71%
1814
21st to endDay
5%5%3442235%6%62%
1577
December1st to 10thDay
46%24334346%60%
1520
11th to 20thDay
5%6%35%445%5%6%8%49%
1926
21st to endDay
36%25%43445%6%57%
2995
January1st to 10thNight
210%45%43445%6%53%
4097
11th to 20thNight
35%24424346%63%
4110
21st to endNight
5%10%35%4345%5%6%52%
4521
February1st to 10thNight
26%35%423345%64%
2470
11th to 20thNight
6%7%35%5%33345%58%
2330
21st to endNight
46%3432435%6%61%
1835
March1st to 10thNight
241442445%7%62%
2090
11th to 20thNight
46%34424446%59%
2068
21st to endNight
5%42442445%7%59%
2178
April1st to 10thNight
44144245%47%62%
1817
11th to 20thNight
4425%5%3435%6%60%
1777
21st to endNight
441442345%6%63%
1800
May1st to 10thNight
4324323347%64%
1732
11th to 20thNight
5%4245%3445%6%57%
1594
21st to endNight
3213323346%68%
1720
June1st to 10thNight
222332445%6%68%
1440
11th to 20thNight
3212223345%73%
1440
21st to endNight
22245%345%7%8%57%
1508
July1st to 10thNight
3325%7%47%8%8%8%45%
1620
11th to 20thNight
5%426%5%47%8%9%10%41%
1620
21st to endNight
46%48%8%47%8%10%12%29%
1773
August1st to 10thNight
4215%7%46%7%8%11%44%
1611
11th to 20thNight
6%5%26%7%47%7%7%9%40%
1706
21st to endNight
43246%346%8%10%49%
1980
September1st to 10thNight
7%425%5%35%6%7%8%46%
1800
11th to 20thNight
342443445%7%59%
1827
21st to endNight
4313223347%68%
2049
October1st to 10thNight
5%32332345%7%63%
2160
11th to 20thNight
3213222335%75%
2160
21st to endNight
331322333473%
2376
November1st to 10thNight
3213322345%72%
2220
11th to 20thNight
3212323435%74%
2343
21st to endNight
5%6%13323345%64%
2602
December1st to 10thNight
5%5%23323346%63%
2660
11th to 20thNight
45%25%5%35%5%47%54%
3271
21st to endNight
47%35%5%34445%57%
4699

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
26%5%10%33%23%3
2859
11th to 20thDay
22%6%15%37%17%3
2860
21st to endDay
33%7%9%26%21%4
3146
February1st to 10thDay
25%5%10%25%25%10%
1710
11th to 20thDay
30%48%22%27%9%
1745
21st to endDay
27%47%18%29%14%
1617
March1st to 10thDay
27%46%20%31%12%
2090
11th to 20thDay
27%5%6%20%30%12%
2058
21st to endDay
26%48%21%30%10%
2178
April1st to 10thDay
23%36%20%31%17%
2142
11th to 20thDay
22%46%18%32%18%
2134
21st to endDay
22%47%20%31%17%
2160
May1st to 10thDay
19%46%16%36%19%
2223
11th to 20thDay
24%6%9%16%29%16%
2304
21st to endDay
20%5%8%12%28%26%
2552
June1st to 10thDay
15%5%6%14%29%32%
2520
11th to 20thDay
12%3411%21%49%
2520
21st to endDay
18%47%15%23%33%
2444
July1st to 10thDay
26%8%12%16%15%24%
2276
11th to 20thDay
24%11%16%23%15%12%
2271
21st to endDay
31%14%18%22%11%4
2404
August1st to 10thDay
33%11%15%15%13%13%
2313
11th to 20thDay
28%9%12%20%18%13%
2192
21st to endDay
24%7%13%21%22%13%
2376
September1st to 10thDay
26%7%10%16%21%19%
2160
11th to 20thDay
22%6%9%16%23%24%
2128
21st to endDay
18%47%17%28%26%
1909
October1st to 10thDay
23%5%10%18%24%21%
1800
11th to 20thDay
15%2313%38%29%
1800
21st to endDay
16%37%20%38%16%
1980
November1st to 10thDay
14%35%23%39%17%
1859
11th to 20thDay
17%36%23%40%10%
1814
21st to endDay
25%36%21%30%14%
1577
December1st to 10thDay
26%410%29%23%9%
1520
11th to 20thDay
31%7%10%23%25%3
1924
21st to endDay
27%5%9%20%24%14%
2995
January1st to 10thNight
31%5%8%29%22%4
4097
11th to 20thNight
22%5%13%35%21%4
4110
21st to endNight
31%6%8%27%24%4
4521
February1st to 10thNight
23%311%24%27%11%
2470
11th to 20thNight
29%46%23%26%11%
2331
21st to endNight
24%5%6%17%35%14%
1835
March1st to 10thNight
20%46%25%32%13%
2090
11th to 20thNight
25%5%7%21%31%12%
2068
21st to endNight
24%49%20%32%11%
2178
April1st to 10thNight
22%46%22%30%16%
1817
11th to 20thNight
24%45%17%30%20%
1777
21st to endNight
22%46%18%33%17%
1800
May1st to 10thNight
21%48%15%32%20%
1732
11th to 20thNight
25%7%10%17%25%17%
1595
21st to endNight
17%5%9%14%28%28%
1720
June1st to 10thNight
16%5%6%14%24%35%
1440
11th to 20thNight
14%35%8%21%49%
1440
21st to endNight
21%6%10%13%19%31%
1508
July1st to 10thNight
30%10%14%13%10%23%
1575
11th to 20thNight
31%11%16%19%10%13%
1566
21st to endNight
39%12%21%17%8%3
1674
August1st to 10thNight
30%13%16%16%12%14%
1602
11th to 20thNight
35%11%14%12%13%15%
1706
21st to endNight
26%8%14%20%19%11%
1980
September1st to 10thNight
31%9%11%15%16%19%
1800
11th to 20thNight
22%6%10%16%19%27%
1827
21st to endNight
19%46%14%29%29%
2049
October1st to 10thNight
21%6%10%17%23%24%
2160
11th to 20thNight
14%35%13%32%33%
2160
21st to endNight
16%35%22%36%19%
2376
November1st to 10thNight
15%35%20%40%17%
2220
11th to 20thNight
13%37%21%40%15%
2343
21st to endNight
22%46%19%34%14%
2602
December1st to 10thNight
23%39%29%27%8%
2660
11th to 20thNight
28%5%11%24%26%6%
3272
21st to endNight
27%6%8%21%27%12%
4699

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
7%434%31%21%3
270
11th to 20thDay
6%14%27%31%18%4
270
21st to endDay
47%23%36%20%10%
297
February1st to 10thDay
311%30%35%16%6%
270
11th to 20thDay
6%7%34%38%14%1
270
21st to endDay
12%16%32%23%15%1
272
March1st to 10thDay
6%18%30%26%18%2
460
11th to 20thDay
9%15%29%27%16%5%
449
21st to endDay
10%22%32%23%11%2
462
April1st to 10thDay
8%14%32%25%15%5%
420
11th to 20thDay
9%18%34%21%14%3
412
21st to endDay
8%15%35%25%13%4
420
May1st to 10thDay
7%10%34%28%18%3
423
11th to 20thDay
8%6%31%26%19%10%
448
21st to endDay
5%10%27%32%20%7%
507
June1st to 10thDay
26%17%35%31%10%
630
11th to 20thDay
2320%38%27%11%
630
21st to endDay
2217%36%31%11%
554
July1st to 10thDay
6%110%25%36%22%
446
11th to 20thDay
4418%36%37%
444
21st to endDay
5%1317%34%40%
487
August1st to 10thDay
5%7%22%39%25%
447
11th to 20thDay
419%25%35%25%
437
21st to endDay
316%20%45%26%
495
September1st to 10thDay
7%210%24%34%24%
450
11th to 20thDay
3313%32%31%18%
450
21st to endDay
6%320%26%28%16%
379
October1st to 10thDay
49%20%25%24%18%
270
11th to 20thDay
6%7%19%28%25%16%
270
21st to endDay
5%8%16%28%30%12%
297
November1st to 10thDay
6%5%21%33%29%6%
270
11th to 20thDay
46%17%34%29%11%
270
21st to endDay
6%11%25%30%17%11%
270
December1st to 10thDay
7%7%26%32%20%9%
270
11th to 20thDay
5%12%26%31%21%4
270
21st to endDay
10%13%26%33%14%5%
297
January1st to 10thNight
7%5%25%39%22%2
760
11th to 20thNight
7%6%25%39%20%3
760
21st to endNight
7%7%23%40%19%4
836
February1st to 10thNight
5%6%33%38%17%2
760
11th to 20thNight
8%8%29%40%13%1
744
21st to endNight
7%10%35%38%10%
628
March1st to 10thNight
48%33%37%16%1
760
11th to 20thNight
6%8%28%40%17%1
752
21st to endNight
6%9%32%37%15%1
792
April1st to 10thNight
410%38%37%10%
557
11th to 20thNight
6%12%34%37%11%
533
21st to endNight
6%8%38%36%11%1
540
May1st to 10thNight
5%6%30%45%14%
540
11th to 20thNight
8%428%42%17%2
531
21st to endNight
45%31%41%18%1
584
June1st to 10thNight
3425%49%18%1
540
11th to 20thNight
3226%48%20%1
540
21st to endNight
1122%46%28%2
540
July1st to 10thNight
3115%43%36%1
525
11th to 20thNight
6%7%34%47%4
522
21st to endNight
6%26%28%51%7%
591
August1st to 10thNight
5%18%31%48%8%
537
11th to 20thNight
6%110%40%37%7%
534
21st to endNight
418%41%43%4
594
September1st to 10thNight
7%211%41%35%3
540
11th to 20thNight
4115%46%30%5%
567
21st to endNight
4117%39%33%5%
720
October1st to 10thNight
5%325%41%24%2
720
11th to 20thNight
3221%45%26%4
720
21st to endNight
45%22%39%25%5%
792
November1st to 10thNight
4221%42%26%4
740
11th to 20thNight
3322%40%26%4
823
21st to endNight
7%9%21%36%23%4
950
December1st to 10thNight
6%6%23%43%19%2
950
11th to 20thNight
8%7%29%36%20%1
950
21st to endNight
8%8%29%38%15%1
936
Page generated at 2024-03-15 12:01:39. Version ac07

Copyright © 2024 Attilla Danko.


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