Fort Richardson State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Richardson State Park clear sky chart from 2005-11-06 to 2024-01-13.

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
46%
24043
31%
74274
19%
23988
58%
23988
40%
38968

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
34%
948
34%
2458
12%
946
49%
946
43%
1379
January11th to 20thNight
36%
915
32%
2379
12%
915
48%
915
41%
1355
January21st to endNight
37%
989
36%
2573
14%
989
51%
989
40%
1471
February1st to 10thNight
28%
720
32%
2160
11%
720
45%
720
36%
1196
February11th to 20thNight
27%
704
26%
2098
9%
700
40%
700
33%
1182
February21st to endNight
19%
592
32%
1776
7%
592
39%
592
31%
1003
March1st to 10thNight
27%
597
28%
2037
12%
597
45%
597
28%
1161
March11th to 20thNight
28%
540
27%
1980
14%
540
45%
540
29%
1046
March21st to endNight
29%
594
28%
2178
15%
594
49%
594
33%
1092
April1st to 10thNight
24%
540
27%
1980
12%
540
45%
540
33%
979
April11th to 20thNight
24%
533
28%
1845
12%
533
46%
533
31%
965
April21st to endNight
28%
540
32%
1620
14%
540
51%
540
39%
875
May1st to 10thNight
30%
540
29%
1620
14%
540
51%
540
36%
905
May11th to 20thNight
36%
531
22%
1594
15%
531
49%
531
37%
901
May21st to endNight
45%
583
25%
1745
17%
582
61%
582
44%
929
June1st to 10thNight
61%
540
24%
1620
19%
540
71%
540
52%
800
June11th to 20thNight
59%
540
28%
1620
25%
540
69%
540
57%
752
June21st to endNight
66%
540
30%
1620
30%
540
73%
540
54%
778
July1st to 10thNight
73%
525
24%
1575
25%
525
78%
525
46%
832
July11th to 20thNight
83%
522
36%
1566
39%
522
88%
522
64%
691
July21st to endNight
83%
591
37%
1673
41%
558
86%
558
60%
768
August1st to 10thNight
84%
537
38%
1601
40%
534
88%
534
63%
708
August11th to 20thNight
76%
534
36%
1653
40%
534
79%
534
46%
843
August21st to endNight
83%
594
31%
2027
37%
594
85%
594
50%
932
September1st to 10thNight
72%
540
29%
1980
32%
540
76%
540
40%
963
September11th to 20thNight
65%
540
25%
1980
27%
540
68%
540
30%
1111
September21st to endNight
69%
540
37%
1980
36%
540
76%
540
44%
919
October1st to 10thNight
62%
540
39%
1980
32%
540
73%
540
46%
884
October11th to 20thNight
49%
675
37%
2115
20%
675
63%
675
46%
1041
October21st to endNight
44%
792
35%
2376
19%
792
55%
792
43%
1238
November1st to 10thNight
47%
791
33%
2271
16%
791
58%
791
47%
1186
November11th to 20thNight
43%
950
33%
2470
15%
950
54%
950
50%
1307
November21st to endNight
34%
950
33%
2470
12%
950
47%
950
38%
1466
December1st to 10thNight
39%
950
36%
2470
15%
950
52%
950
43%
1404
December11th to 20thNight
35%
948
33%
2855
13%
948
47%
948
32%
1646
December21st to endNight
32%
1038
21%
4329
12%
1026
45%
1026
27%
2260

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
8%42442445%7%55%
74909
Night
8%42332345%7%59%
74865
TransparencyDay
30%39%24%25%9%
74634
Night
27%28%23%27%13%
74660
SeeingDay
10%7%24%30%21%7%
14025
Night
10%8%32%35%14%1
24055

By Month

Percentage Cloud Cover SE (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
8%5%24423345%59%
1707
11th to 20thDay
12%314423346%58%
1643
21st to endDay
10%5%1442345%6%56%
1799
February1st to 10thDay
12%5%24323336%55%
1800
11th to 20thDay
13%6%24434435%51%
1749
21st to endDay
17%6%34212335%55%
1480
March1st to 10thDay
14%6%25%32445%7%48%
1921
11th to 20thDay
13%5%245%2443454%
1980
21st to endDay
9%5%245%3445%6%53%
2178
April1st to 10thDay
8%42442445%6%56%
1980
11th to 20thDay
10%5%25%43445%5%54%
2059
21st to endDay
9%5%25%5%24446%55%
2340
May1st to 10thDay
10%425%5%2445%7%53%
2340
11th to 20thDay
11%5%245%35%5%6%8%48%
2302
21st to endDay
9%6%345%35%6%7%9%43%
2531
June1st to 10thDay
5%4234245%7%10%54%
2340
11th to 20thDay
4214335%5%5%9%59%
2340
21st to endDay
5%3244245%5%8%60%
2340
July1st to 10thDay
6%3246%45%6%6%10%46%
2340
11th to 20thDay
42133245%6%9%61%
2340
21st to endDay
22145%35%6%7%10%54%
2546
August1st to 10thDay
22135%345%5%8%62%
2328
11th to 20thDay
6%415%5%45%5%6%9%49%
2244
21st to endDay
43234345%7%9%56%
2327
September1st to 10thDay
9%42442445%6%56%
1980
11th to 20thDay
12%6%24435%5%6%7%46%
1980
21st to endDay
8%31442445%7%58%
1980
October1st to 10thDay
432442435%6%62%
1980
11th to 20thDay
8%42322234467%
1825
21st to endDay
12%42342223464%
1980
November1st to 10thDay
8%41332335%6%62%
1804
11th to 20thDay
5%31332345%6%65%
1710
21st to endDay
13%5%23323345%58%
1710
December1st to 10thDay
11%6%24424446%53%
1710
11th to 20thDay
10%5%245%35%45%5%52%
2161
21st to endDay
11%6%25%43344453%
3135
January1st to 10thNight
8%32332345%6%60%
2458
11th to 20thNight
10%5%23423235%62%
2379
21st to endNight
9%5%24323445%60%
2573
February1st to 10thNight
10%5%25%423345%57%
2160
11th to 20thNight
11%6%23324346%54%
2098
21st to endNight
13%5%2442323458%
1776
March1st to 10thNight
11%4345%3445%7%51%
2037
11th to 20thNight
12%5%23423347%54%
1980
21st to endNight
7%42442445%6%58%
2178
April1st to 10thNight
7%42342445%8%55%
1980
11th to 20thNight
9%5%24324446%57%
1845
21st to endNight
9%5%1332345%7%58%
1620
May1st to 10thNight
7%5%234245%5%8%54%
1620
11th to 20thNight
9%43442345%9%53%
1593
21st to endNight
6%3143245%7%9%57%
1745
June1st to 10thNight
32233235%8%12%57%
1620
11th to 20thNight
221233445%12%63%
1620
21st to endNight
222432345%7%68%
1620
July1st to 10thNight
4323425%5%8%11%53%
1620
11th to 20thNight
22122335%8%71%
1620
21st to endNight
111332346%13%62%
1772
August1st to 10thNight
221221345%9%69%
1611
11th to 20thNight
431443446%9%57%
1653
21st to endNight
32143245%6%10%61%
2027
September1st to 10thNight
8%323333347%59%
1980
11th to 20thNight
11%5%25%5%2445%7%49%
1980
21st to endNight
6%21333345%7%63%
1980
October1st to 10thNight
5%21332345%8%62%
1980
11th to 20thNight
9%323322235%67%
2115
21st to endNight
11%423322235%65%
2376
November1st to 10thNight
7%413323345%65%
2271
11th to 20thNight
3314323446%66%
2470
21st to endNight
12%423424346%56%
2470
December1st to 10thNight
9%5%23323346%60%
2470
11th to 20thNight
9%6%24423446%54%
3036
21st to endNight
11%6%34323345%56%
4532

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
30%25%21%31%11%
1708
11th to 20thDay
29%16%22%33%9%
1643
21st to endDay
30%25%22%30%12%
1799
February1st to 10thDay
32%26%21%27%12%
1800
11th to 20thDay
38%15%21%23%11%
1759
21st to endDay
36%1315%27%18%
1480
March1st to 10thDay
38%25%18%24%13%
1921
11th to 20thDay
37%28%19%25%9%
1980
21st to endDay
33%39%24%21%10%
2178
April1st to 10thDay
31%29%25%20%13%
1980
11th to 20thDay
34%28%21%20%15%
2059
21st to endDay
32%28%23%27%7%
2340
May1st to 10thDay
33%39%25%21%9%
2340
11th to 20thDay
36%313%24%22%3
2306
21st to endDay
37%5%14%25%17%3
2531
June1st to 10thDay
26%417%30%19%4
2340
11th to 20thDay
23%412%32%24%6%
2340
21st to endDay
24%412%25%28%8%
2340
July1st to 10thDay
32%416%29%16%2
2276
11th to 20thDay
21%310%33%28%5%
2271
21st to endDay
22%414%35%24%1
2405
August1st to 10thDay
20%312%32%28%4
2314
11th to 20thDay
31%413%26%23%3
2244
21st to endDay
24%313%31%23%6%
2327
September1st to 10thDay
30%38%22%27%10%
1980
11th to 20thDay
37%48%20%22%9%
1980
21st to endDay
26%36%24%28%14%
1980
October1st to 10thDay
24%29%24%25%16%
1980
11th to 20thDay
24%25%18%31%20%
1825
21st to endDay
29%1421%28%17%
1980
November1st to 10thDay
26%28%23%28%13%
1804
11th to 20thDay
21%28%23%32%14%
1710
21st to endDay
32%2421%27%14%
1710
December1st to 10thDay
34%25%24%27%8%
1710
11th to 20thDay
36%26%18%26%12%
2159
21st to endDay
37%1325%23%11%
3135
January1st to 10thNight
26%26%21%30%15%
2458
11th to 20thNight
28%26%19%31%14%
2379
21st to endNight
29%2318%31%18%
2573
February1st to 10thNight
32%26%20%26%15%
2160
11th to 20thNight
33%27%17%27%14%
2098
21st to endNight
34%15%17%22%21%
1776
March1st to 10thNight
36%35%17%23%17%
2037
11th to 20thNight
33%28%21%25%11%
1980
21st to endNight
28%310%22%26%10%
2178
April1st to 10thNight
28%210%23%21%16%
1980
11th to 20thNight
30%210%20%21%17%
1845
21st to endNight
27%310%23%29%7%
1620
May1st to 10thNight
30%410%22%24%11%
1620
11th to 20thNight
31%414%25%21%5%
1594
21st to endNight
26%418%28%21%3
1746
June1st to 10thNight
20%317%36%19%5%
1620
11th to 20thNight
16%414%33%25%8%
1620
21st to endNight
18%312%26%31%10%
1620
July1st to 10thNight
24%414%33%21%3
1575
11th to 20thNight
13%38%35%33%8%
1566
21st to endNight
15%311%39%29%3
1673
August1st to 10thNight
14%29%34%34%7%
1601
11th to 20thNight
24%310%32%26%6%
1653
21st to endNight
19%412%31%27%8%
2027
September1st to 10thNight
26%38%25%27%11%
1980
11th to 20thNight
36%310%18%22%12%
1980
21st to endNight
22%35%22%30%17%
1980
October1st to 10thNight
21%29%26%24%17%
1980
11th to 20thNight
23%27%15%28%24%
2115
21st to endNight
27%1421%28%20%
2376
November1st to 10thNight
25%27%21%27%18%
2271
11th to 20thNight
22%26%23%31%16%
2470
21st to endNight
32%15%17%29%15%
2470
December1st to 10thNight
28%25%24%28%13%
2470
11th to 20thNight
33%1418%30%14%
3037
21st to endNight
34%1418%29%14%
4532

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
13%15%38%28%6%
270
11th to 20thDay
14%17%39%20%9%1
248
21st to endDay
14%14%43%22%7%
264
February1st to 10thDay
19%15%39%21%7%
240
11th to 20thDay
24%14%39%20%3
240
21st to endDay
24%16%40%17%3
198
March1st to 10thDay
20%20%33%22%5%
240
11th to 20thDay
20%17%35%23%42
240
21st to endDay
12%17%45%18%5%2
264
April1st to 10thDay
13%18%39%21%8%1
240
11th to 20thDay
18%13%44%20%5%
337
21st to endDay
14%15%41%22%7%2
600
May1st to 10thDay
12%9%37%32%8%
603
11th to 20thDay
14%6%34%30%12%3
625
21st to endDay
12%6%30%33%15%4
679
June1st to 10thDay
7%316%41%27%8%
630
11th to 20thDay
4122%44%22%7%
630
21st to endDay
4213%40%31%10%
630
July1st to 10thDay
6%18%36%31%17%
621
11th to 20thDay
36%31%47%14%
618
21st to endDay
35%30%44%18%
684
August1st to 10thDay
215%35%42%15%
626
11th to 20thDay
6%36%34%40%13%
558
21st to endDay
416%33%35%22%
446
September1st to 10thDay
8%1423%45%20%
270
11th to 20thDay
5%15%28%40%21%
270
21st to endDay
13%26%31%33%14%
270
October1st to 10thDay
3121%37%29%9%
270
11th to 20thDay
11%7%30%33%17%2
270
21st to endDay
23%6%30%26%14%2
297
November1st to 10thDay
15%337%30%11%3
270
11th to 20thDay
10%10%32%33%13%3
270
21st to endDay
17%12%40%21%9%1
270
December1st to 10thDay
18%10%33%25%13%1
270
11th to 20thDay
11%10%41%28%9%
270
21st to endDay
20%11%35%27%7%
297
January1st to 10thNight
10%10%41%29%9%
950
11th to 20thNight
14%13%33%32%8%
915
21st to endNight
12%12%35%33%6%
989
February1st to 10thNight
13%12%44%25%6%
720
11th to 20thNight
13%15%41%25%5%
704
21st to endNight
18%14%46%20%2
592
March1st to 10thNight
12%15%42%26%5%
597
11th to 20thNight
15%12%42%26%6%
540
21st to endNight
9%16%43%27%6%
594
April1st to 10thNight
11%12%50%22%4
540
11th to 20thNight
12%16%46%23%3
533
21st to endNight
12%12%46%23%7%
540
May1st to 10thNight
9%11%46%27%6%1
540
11th to 20thNight
10%7%41%29%12%1
531
21st to endNight
7%339%37%12%1
584
June1st to 10thNight
4227%44%21%1
540
11th to 20thNight
1133%51%13%
540
21st to endNight
2123%48%24%2
540
July1st to 10thNight
5%114%45%32%4
525
11th to 20thNight
310%54%31%2
522
21st to endNight
218%53%34%2
591
August1st to 10thNight
28%54%34%2
537
11th to 20thNight
6%17%47%35%3
534
21st to endNight
425%45%39%5%
594
September1st to 10thNight
8%111%43%33%4
540
11th to 20thNight
13%311%43%30%2
540
21st to endNight
7%117%47%26%2
540
October1st to 10thNight
5%227%45%20%1
540
11th to 20thNight
11%6%31%37%13%1
675
21st to endNight
13%8%32%34%11%1
792
November1st to 10thNight
10%435%35%14%2
791
11th to 20thNight
5%9%39%34%11%1
950
21st to endNight
14%9%39%28%9%1
950
December1st to 10thNight
12%9%37%35%7%
950
11th to 20thNight
15%10%36%33%6%
950
21st to endNight
14%11%39%30%6%
1045
Page generated at 2024-01-10 18:35:26. Version ac07

Copyright 2024 Attilla Danko


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