Riverton
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Riverton clear sky chart from 2005-11-06 to 2024-03-23.

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
57%
25004
23%
80475
17%
24933
63%
24933
36%
44606

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
55%
933
19%
4350
12%
926
62%
926
24%
2409
January11th to 20thNight
49%
849
21%
4218
16%
835
57%
835
22%
2302
January21st to endNight
53%
825
15%
4435
18%
814
62%
814
21%
2334
February1st to 10thNight
43%
760
21%
2470
14%
760
54%
760
30%
1453
February11th to 20thNight
50%
740
18%
2403
14%
740
56%
740
30%
1404
February21st to endNight
44%
628
22%
1960
14%
628
54%
628
34%
1108
March1st to 10thNight
49%
760
24%
2121
13%
760
60%
760
38%
1255
March11th to 20thNight
52%
760
23%
2090
13%
760
59%
760
40%
1234
March21st to endNight
48%
793
18%
2193
11%
793
54%
793
32%
1385
April1st to 10thNight
43%
540
20%
1800
14%
540
52%
540
29%
1034
April11th to 20thNight
43%
533
16%
1777
14%
533
48%
533
24%
1133
April21st to endNight
49%
540
21%
1648
15%
540
54%
540
29%
1018
May1st to 10thNight
51%
540
17%
1597
13%
540
54%
540
29%
994
May11th to 20thNight
54%
531
20%
1418
16%
531
56%
531
31%
922
May21st to endNight
55%
583
16%
1552
12%
582
57%
582
32%
1003
June1st to 10thNight
63%
540
19%
1440
13%
540
67%
540
43%
828
June11th to 20thNight
59%
540
21%
1440
15%
540
63%
540
44%
828
June21st to endNight
74%
540
26%
1440
21%
540
77%
540
57%
738
July1st to 10thNight
75%
525
20%
1400
18%
525
77%
525
58%
710
July11th to 20thNight
77%
522
29%
1392
26%
522
80%
522
66%
655
July21st to endNight
81%
591
30%
1611
28%
558
83%
558
58%
756
August1st to 10thNight
76%
537
29%
1602
26%
534
77%
534
51%
768
August11th to 20thNight
80%
534
34%
1602
28%
534
82%
534
58%
734
August21st to endNight
76%
594
33%
1919
34%
594
78%
594
53%
874
September1st to 10thNight
70%
540
32%
1800
31%
540
76%
540
47%
852
September11th to 20thNight
67%
577
33%
1837
30%
577
74%
577
47%
898
September21st to endNight
68%
720
33%
2041
24%
720
73%
720
52%
1050
October1st to 10thNight
57%
720
23%
2160
18%
720
61%
720
34%
1277
October11th to 20thNight
57%
720
30%
2160
19%
720
66%
720
42%
1147
October21st to endNight
58%
792
30%
2376
20%
792
66%
792
39%
1320
November1st to 10thNight
55%
871
26%
2408
15%
871
62%
871
42%
1364
November11th to 20thNight
50%
950
26%
2660
16%
950
58%
950
38%
1555
November21st to endNight
54%
950
24%
2660
15%
950
61%
950
39%
1562
December1st to 10thNight
52%
950
21%
2660
12%
950
59%
950
38%
1554
December11th to 20thNight
53%
948
22%
3148
14%
948
59%
948
32%
1740
December21st to endNight
45%
1028
12%
4687
9%
1026
53%
1026
22%
2408

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
4424435%6%7%10%52%
78775
Night
45%35%5%35%5%7%10%49%
81179
TransparencyDay
25%7%15%27%19%7%
78486
Night
28%7%16%26%17%6%
80990
SeeingDay
7%6%21%36%23%7%
14791
Night
6%425%46%18%1
25062

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
1327%8%46%8%12%14%35%
2538
11th to 20thDay
1437%7%46%7%8%12%42%
2728
21st to endDay
1325%437%10%11%14%40%
3146
February1st to 10thDay
26%36%7%36%6%8%9%44%
1710
11th to 20thDay
25%37%6%347%8%10%44%
1665
21st to endDay
1445%5%46%5%7%11%49%
1494
March1st to 10thDay
25%25%4446%8%11%49%
2057
11th to 20thDay
36%25%435%6%6%10%51%
2090
21st to endDay
5%6%35%6%45%5%7%10%44%
2206
April1st to 10thDay
6%6%24435%5%6%10%48%
2160
11th to 20thDay
6%7%47%5%36%6%7%8%41%
2131
21st to endDay
9%8%36%6%45%6%6%8%40%
2308
May1st to 10thDay
9%7%25%5%35%5%7%9%43%
2362
11th to 20thDay
10%6%245%35%5%7%11%43%
2478
21st to endDay
10%5%24436%6%8%12%41%
2724
June1st to 10thDay
4323425%5%7%11%53%
2520
11th to 20thDay
5%2233245%6%8%59%
2520
21st to endDay
23133235%6%8%64%
2520
July1st to 10thDay
32133245%7%9%62%
2520
11th to 20thDay
1213325%5%5%8%64%
2520
21st to endDay
32123245%7%10%60%
2608
August1st to 10thDay
3313335%6%6%9%58%
2328
11th to 20thDay
23124245%6%10%61%
2299
21st to endDay
231232446%8%66%
2435
September1st to 10thDay
432233435%7%64%
2160
11th to 20thDay
6%212323347%66%
2120
21st to endDay
6%31332235%5%66%
1918
October1st to 10thDay
9%6%2442445%6%55%
1800
11th to 20thDay
6%423334348%60%
1800
21st to endDay
4425%5%2445%9%55%
1980
November1st to 10thDay
24244346%6%10%57%
1650
11th to 20thDay
1424436%7%7%9%53%
1520
21st to endDay
27%35%4346%5%10%51%
1520
December1st to 10thDay
2435%6%35%6%8%11%46%
1520
11th to 20thDay
2422435%6%9%13%49%
1926
21st to endDay
26%35%445%6%10%15%40%
2794
January1st to 10thNight
17%36%6%47%8%10%13%36%
4417
11th to 20thNight
1439%6%36%6%9%13%39%
4270
21st to endNight
25%26%6%47%10%10%13%34%
4521
February1st to 10thNight
26%37%6%36%5%7%9%45%
2470
11th to 20thNight
25%36%6%37%6%7%9%45%
2402
21st to endNight
27%46%6%35%5%7%8%50%
1960
March1st to 10thNight
26%36%5%45%5%5%9%49%
2121
11th to 20thNight
36%36%4345%7%10%50%
2090
21st to endNight
5%7%36%6%35%6%6%9%45%
2193
April1st to 10thNight
7%6%35%4346%5%8%48%
1800
11th to 20thNight
8%8%36%5%45%5%7%8%40%
1777
21st to endNight
10%9%36%43446%7%44%
1648
May1st to 10thNight
12%7%25%44345%7%46%
1597
11th to 20thNight
11%7%345%25%5%6%8%42%
1417
21st to endNight
12%5%245%35%6%6%9%42%
1552
June1st to 10thNight
5%4244345%6%10%55%
1440
11th to 20thNight
8%42443445%8%56%
1440
21st to endNight
431332245%7%67%
1440
July1st to 10thNight
211342448%10%62%
1440
11th to 20thNight
11112245%5%7%70%
1440
21st to endNight
221222446%9%66%
1706
August1st to 10thNight
2213435%6%7%9%58%
1611
11th to 20thNight
211222446%8%67%
1602
21st to endNight
231332445%9%64%
1919
September1st to 10thNight
43134245%47%64%
1800
11th to 20thNight
5%3234235%6%6%62%
1837
21st to endNight
7%313223346%66%
2041
October1st to 10thNight
10%7%2442445%6%51%
2160
11th to 20thNight
6%424323447%59%
2160
21st to endNight
47%25%43345%8%55%
2376
November1st to 10thNight
34244346%7%9%55%
2408
11th to 20thNight
3435%5%45%6%7%9%51%
2660
21st to endNight
37%35%5%3346%8%52%
2660
December1st to 10thNight
25%36%5%35%5%7%9%50%
2660
11th to 20thNight
16%35%435%6%8%15%44%
3271
21st to endNight
27%36%5%36%7%10%15%37%
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
31%8%18%31%11%1
2539
11th to 20thDay
30%10%21%25%12%1
2728
21st to endDay
22%13%27%27%9%1
3146
February1st to 10thDay
33%7%19%30%10%1
1710
11th to 20thDay
31%7%20%26%13%2
1674
21st to endDay
28%5%20%28%17%2
1494
March1st to 10thDay
25%7%17%34%15%2
2057
11th to 20thDay
26%6%18%33%15%1
2090
21st to endDay
34%7%16%32%10%1
2206
April1st to 10thDay
31%7%19%27%13%3
2160
11th to 20thDay
36%7%15%26%14%1
2134
21st to endDay
39%7%12%26%15%1
2308
May1st to 10thDay
35%8%15%28%13%2
2362
11th to 20thDay
34%8%14%27%14%2
2482
21st to endDay
31%10%18%27%13%1
2724
June1st to 10thDay
24%7%17%27%20%5%
2520
11th to 20thDay
21%6%13%21%26%13%
2520
21st to endDay
16%5%9%24%30%16%
2520
July1st to 10thDay
17%6%10%25%26%16%
2451
11th to 20thDay
17%47%19%28%25%
2445
21st to endDay
17%5%9%20%27%21%
2463
August1st to 10thDay
20%5%12%22%25%17%
2313
11th to 20thDay
18%5%10%24%28%16%
2299
21st to endDay
16%5%8%19%33%18%
2435
September1st to 10thDay
20%48%18%31%19%
2160
11th to 20thDay
18%49%27%26%16%
2120
21st to endDay
20%47%28%33%7%
1918
October1st to 10thDay
30%6%11%28%20%5%
1800
11th to 20thDay
25%5%12%34%19%5%
1800
21st to endDay
26%5%16%30%20%3
1980
November1st to 10thDay
23%6%17%29%22%4
1650
11th to 20thDay
23%8%18%30%18%4
1520
21st to endDay
28%6%17%29%18%2
1520
December1st to 10thDay
28%9%21%26%15%2
1520
11th to 20thDay
22%9%24%35%9%1
1924
21st to endDay
28%6%16%32%16%1
2794
January1st to 10thNight
32%9%22%28%8%1
4417
11th to 20thNight
29%12%23%20%14%3
4270
21st to endNight
28%13%27%23%8%1
4521
February1st to 10thNight
33%8%19%29%11%1
2470
11th to 20thNight
31%9%17%28%13%2
2403
21st to endNight
31%6%18%25%19%2
1960
March1st to 10thNight
30%6%15%32%14%2
2121
11th to 20thNight
29%6%19%31%14%1
2090
21st to endNight
35%7%17%29%10%2
2193
April1st to 10thNight
33%6%17%26%14%4
1800
11th to 20thNight
40%7%14%23%14%1
1777
21st to endNight
38%5%11%29%16%1
1648
May1st to 10thNight
37%6%12%27%15%3
1597
11th to 20thNight
36%8%13%27%12%3
1418
21st to endNight
36%7%15%27%13%2
1552
June1st to 10thNight
23%9%19%25%18%6%
1440
11th to 20thNight
25%6%11%19%24%15%
1440
21st to endNight
15%6%8%19%32%20%
1440
July1st to 10thNight
16%5%13%25%24%17%
1400
11th to 20thNight
12%410%19%30%26%
1392
21st to endNight
16%48%21%28%24%
1611
August1st to 10thNight
18%5%11%28%21%16%
1602
11th to 20thNight
14%5%9%23%32%17%
1602
21st to endNight
17%410%18%31%19%
1919
September1st to 10thNight
20%48%17%30%20%
1800
11th to 20thNight
20%6%9%23%27%15%
1837
21st to endNight
21%48%27%32%10%
2041
October1st to 10thNight
32%7%11%26%18%7%
2160
11th to 20thNight
26%411%32%22%6%
2160
21st to endNight
28%5%12%31%20%4
2376
November1st to 10thNight
24%8%16%29%19%4
2408
11th to 20thNight
29%6%14%33%15%3
2660
21st to endNight
29%6%15%30%17%2
2660
December1st to 10thNight
29%6%19%27%15%3
2660
11th to 20thNight
26%9%21%33%10%1
3272
21st to endNight
30%8%16%28%15%3
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%320%45%21%6%
270
11th to 20thDay
3419%44%23%5%
270
21st to endDay
4317%48%21%6%
297
February1st to 10thDay
3437%43%11%2
270
11th to 20thDay
2328%48%16%2
270
21st to endDay
27%23%48%18%2
225
March1st to 10thDay
7%9%28%41%14%2
427
11th to 20thDay
7%9%29%38%15%3
460
21st to endDay
10%11%29%32%16%2
471
April1st to 10thDay
9%15%27%33%15%3
420
11th to 20thDay
11%17%31%29%12%1
412
21st to endDay
15%15%22%26%19%4
420
May1st to 10thDay
12%13%23%29%18%5%
445
11th to 20thDay
16%5%16%32%24%6%
625
21st to endDay
13%5%21%26%24%11%
679
June1st to 10thDay
5%6%21%29%29%11%
630
11th to 20thDay
7%7%24%34%22%5%
630
21st to endDay
35%17%39%29%7%
630
July1st to 10thDay
4314%33%36%11%
621
11th to 20thDay
3215%39%33%8%
618
21st to endDay
3216%35%32%12%
550
August1st to 10thDay
4415%36%29%12%
447
11th to 20thDay
3316%31%33%15%
437
21st to endDay
3416%32%32%14%
495
September1st to 10thDay
5%418%35%27%11%
450
11th to 20thDay
5%7%19%28%28%14%
450
21st to endDay
9%6%16%28%28%12%
388
October1st to 10thDay
11%6%13%28%26%15%
270
11th to 20thDay
6%7%22%32%25%8%
270
21st to endDay
8%5%23%41%18%4
297
November1st to 10thDay
5%6%24%41%16%7%
270
11th to 20thDay
4423%42%20%6%
270
21st to endDay
6%321%43%22%4
270
December1st to 10thDay
3219%52%19%5%
270
11th to 20thDay
7%222%48%18%4
270
21st to endDay
45%21%48%14%8%
297
January1st to 10thNight
3328%48%16%2
950
11th to 20thNight
3432%45%13%3
855
21st to endNight
5%325%51%14%1
836
February1st to 10thNight
5%435%44%11%1
760
11th to 20thNight
3330%48%13%2
744
21st to endNight
45%35%46%10%
628
March1st to 10thNight
5%433%45%13%1
760
11th to 20thNight
5%331%47%13%
760
21st to endNight
7%5%31%44%12%1
793
April1st to 10thNight
12%6%33%40%8%1
540
11th to 20thNight
13%5%31%40%11%
533
21st to endNight
12%7%26%41%13%1
540
May1st to 10thNight
14%5%22%38%20%1
540
11th to 20thNight
15%419%36%25%2
531
21st to endNight
13%420%38%23%1
584
June1st to 10thNight
5%423%38%27%3
540
11th to 20thNight
9%324%49%15%
540
21st to endNight
4315%50%27%1
540
July1st to 10thNight
414%48%33%1
525
11th to 20thNight
2116%56%24%1
522
21st to endNight
3111%50%34%2
591
August1st to 10thNight
3113%51%32%1
537
11th to 20thNight
2113%49%33%1
534
21st to endNight
3214%45%35%2
594
September1st to 10thNight
6%217%47%25%3
540
11th to 20thNight
5%220%43%27%3
577
21st to endNight
9%317%39%28%4
720
October1st to 10thNight
14%320%40%20%3
720
11th to 20thNight
8%325%43%19%2
720
21st to endNight
7%425%48%15%2
792
November1st to 10thNight
45%30%46%14%1
871
11th to 20thNight
5%6%31%45%11%1
950
21st to endNight
6%327%48%15%1
950
December1st to 10thNight
4331%49%12%1
950
11th to 20thNight
5%430%50%11%1
950
21st to endNight
6%5%30%46%11%2
1045
Page generated at 2024-03-19 21:31:09. Version ac07

Copyright © 2024 Attilla Danko.


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