West Jordan
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the West Jordan clear sky chart from 2005-11-05 to 2018-10-08.

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
57%
17197
21%
51322
18%
17161
60%
17161
30%
31650

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 15thNight
47%
776
13%
2522
12%
776
50%
776
17%
1798
January16th to endNight
52%
832
14%
2704
15%
832
53%
832
18%
1941
February1st to 15thNight
51%
760
12%
2483
14%
760
54%
760
20%
1721
February16th to endNight
44%
684
18%
2062
15%
684
49%
684
22%
1418
March1st to 15thNight
50%
780
18%
2187
15%
780
55%
780
26%
1473
March16th to endNight
46%
832
17%
2288
12%
832
50%
832
25%
1565
April1st to 15thNight
44%
704
18%
2024
12%
704
48%
704
26%
1326
April16th to endNight
51%
579
22%
1737
15%
579
56%
579
29%
1081
May1st to 15thNight
57%
584
23%
1754
17%
584
61%
584
33%
1021
May16th to endNight
61%
609
17%
1829
16%
609
63%
609
33%
1079
June1st to 15thNight
62%
585
23%
1687
20%
585
67%
585
42%
895
June16th to endNight
69%
585
27%
1727
23%
585
77%
585
59%
781
July1st to 15thNight
69%
555
18%
1665
17%
555
72%
555
39%
915
July16th to endNight
75%
612
23%
1737
21%
579
76%
579
41%
955
August1st to 15thNight
70%
575
26%
1719
19%
572
75%
572
43%
904
August16th to endNight
74%
621
34%
1873
28%
621
77%
621
48%
948
September1st to 15thNight
74%
747
31%
2112
24%
747
80%
747
50%
1093
September16th to endNight
72%
776
35%
2145
28%
776
75%
776
52%
1116
October1st to 15thNight
60%
752
27%
2184
19%
752
66%
752
38%
1244
October16th to endNight
64%
768
31%
2310
27%
768
68%
768
37%
1307
November1st to 15thNight
55%
760
23%
2470
22%
760
58%
760
29%
1473
November16th to endNight
53%
839
22%
2594
19%
839
57%
839
29%
1585
December1st to 15thNight
47%
975
13%
2730
11%
975
49%
975
24%
1897
December16th to endNight
39%
907
13%
2779
11%
907
41%
907
15%
2114

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
6%6%2442445%7%49%
51768
Night
7%7%2442445%7%49%
51517
TransparencyDay
33%8%10%18%18%10%
51463
Night
34%7%11%19%17%9%
51323
SeeingDay
7%17%33%29%9%1
6749
Night
10%7%19%33%23%4
17208

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 15thDay
10%13%5%7%7%25%5%46%31%
1746
16th to endDay
10%14%46%5%35%5%5%6%32%
1872
February1st to 15thDay
10%11%5%7%6%345%46%34%
1710
16th to endDay
6%14%6%8%6%245%5%7%32%
1697
March1st to 15thDay
410%35%5%35%6%6%7%41%
2101
16th to endDay
8%10%37%5%345%6%7%36%
2288
April1st to 15thDay
9%8%45%5%345%5%6%41%
2251
16th to endDay
7%6%25%4245%6%7%46%
2498
May1st to 15thDay
6%4244245%6%9%48%
2526
16th to endDay
6%424435%6%7%8%45%
2637
June1st to 15thDay
332432345%8%57%
2584
16th to endDay
21121223476%
2541
July1st to 15thDay
221332446%8%59%
2535
16th to endDay
3213335%5%6%8%56%
2675
August1st to 15thDay
3113325%5%7%8%57%
2485
16th to endDay
221331346%7%61%
2681
September1st to 15thDay
321231345%6%65%
2176
16th to endDay
6%111212236%67%
2145
October1st to 15thDay
7%424425%446%52%
1943
16th to endDay
7%6%23423446%55%
1911
November1st to 15thDay
10%7%245%245%46%48%
1719
16th to endDay
9%8%46%5%33446%44%
1680
December1st to 15thDay
11%10%47%42445%7%36%
1560
16th to endDay
13%15%5%8%424346%28%
1807
January1st to 15thNight
12%10%36%6%245%5%7%34%
2522
16th to endNight
9%13%45%5%36%45%6%34%
2704
February1st to 15thNight
9%10%36%5%35%5%5%8%37%
2472
16th to endNight
6%11%5%6%5%24448%38%
2062
March1st to 15thNight
6%11%35%4335%6%6%43%
2187
16th to endNight
7%9%245%345%7%8%40%
2288
April1st to 15thNight
10%8%345%25%436%46%
2024
16th to endNight
8%6%244245%5%6%49%
1737
May1st to 15thNight
5%42442447%8%52%
1754
16th to endNight
8%32432445%8%51%
1828
June1st to 15thNight
4313423446%61%
1687
16th to endNight
112212347%71%
1727
July1st to 15thNight
22145%3446%8%54%
1755
16th to endNight
22234345%7%9%54%
1845
August1st to 15thNight
22134345%5%8%57%
1728
16th to endNight
121342346%7%61%
1873
September1st to 15thNight
2213323446%65%
2112
16th to endNight
6%21231224469%
2145
October1st to 15thNight
7%323323446%58%
2184
16th to endNight
6%5%14323437%57%
2310
November1st to 15thNight
8%7%24423347%50%
2470
16th to endNight
9%7%3342345%7%48%
2594
December1st to 15thNight
11%10%35%433446%41%
2730
16th to endNight
16%13%5%7%5%34336%29%
2779

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 15thDay
52%9%16%16%3
1747
16th to endDay
52%10%13%13%7%1
1872
February1st to 15thDay
52%9%12%15%8%
1710
16th to endDay
50%10%14%17%6%
1697
March1st to 15thDay
39%12%14%20%10%1
2101
16th to endDay
46%10%14%18%7%3
2288
April1st to 15thDay
42%10%12%19%13%2
2251
16th to endDay
34%9%11%21%20%1
2498
May1st to 15thDay
30%9%10%23%20%5%
2526
16th to endDay
33%11%11%21%19%3
2640
June1st to 15thDay
24%6%8%18%30%11%
2584
16th to endDay
12%35%10%33%34%
2541
July1st to 15thDay
20%7%7%13%23%28%
2396
16th to endDay
22%7%8%10%23%27%
2520
August1st to 15thDay
21%7%8%14%19%27%
2470
16th to endDay
19%5%7%15%31%19%
2681
September1st to 15thDay
17%8%6%15%30%21%
2176
16th to endDay
18%6%7%20%30%15%
2145
October1st to 15thDay
31%8%9%24%22%4
1943
16th to endDay
29%7%11%27%20%2
1911
November1st to 15thDay
38%8%12%22%15%3
1719
16th to endDay
41%7%12%24%11%
1680
December1st to 15thDay
48%10%16%18%6%
1560
16th to endDay
57%8%12%15%5%
1807
January1st to 15thNight
50%7%16%18%6%1
2522
16th to endNight
50%8%14%15%9%2
2704
February1st to 15thNight
47%7%15%17%11%
2483
16th to endNight
44%7%12%24%9%
2062
March1st to 15thNight
40%8%12%23%13%1
2187
16th to endNight
39%10%13%22%10%3
2288
April1st to 15thNight
39%7%11%21%16%3
2024
16th to endNight
34%8%12%20%22%2
1737
May1st to 15thNight
28%8%10%23%23%5%
1755
16th to endNight
30%8%13%25%17%5%
1829
June1st to 15thNight
23%410%17%30%13%
1687
16th to endNight
14%36%9%29%37%
1727
July1st to 15thNight
27%5%8%13%16%29%
1665
16th to endNight
24%7%8%13%19%27%
1737
August1st to 15thNight
22%6%10%14%18%27%
1719
16th to endNight
20%5%8%12%29%22%
1873
September1st to 15thNight
20%47%16%25%25%
2112
16th to endNight
19%45%16%30%22%
2145
October1st to 15thNight
27%6%10%24%23%7%
2184
16th to endNight
27%7%9%22%28%4
2310
November1st to 15thNight
35%5%11%22%18%6%
2470
16th to endNight
35%7%14%25%14%2
2594
December1st to 15thNight
44%8%15%21%9%1
2730
16th to endNight
57%6%12%16%6%
2779

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 15thDay
21%12%22%23%18%1
135
16th to endDay
14%13%25%29%15%2
144
February1st to 15thDay
14%20%23%22%15%2
135
16th to endDay
7%26%43%18%4
278
March1st to 15thDay
10%22%35%25%5%
330
16th to endDay
13%29%34%19%3
352
April1st to 15thDay
12%30%29%19%6%1
329
16th to endDay
12%31%28%20%6%
318
May1st to 15thDay
7%25%38%20%7%1
348
16th to endDay
6%19%31%29%11%1
394
June1st to 15thDay
418%31%33%9%2
424
16th to endDay
214%37%35%7%1
381
July1st to 15thDay
27%29%46%11%3
365
16th to endDay
2346%36%8%2
391
August1st to 15thDay
48%40%37%8%1
359
16th to endDay
37%36%37%12%2
396
September1st to 15thDay
210%38%31%13%2
375
16th to endDay
7%12%27%37%13%1
375
October1st to 15thDay
6%25%31%23%12%
227
16th to endDay
11%18%25%29%15%1
144
November1st to 15thDay
10%20%22%25%16%4
135
16th to endDay
15%18%28%25%10%1
135
December1st to 15thDay
12%17%29%24%11%3
135
16th to endDay
16%20%20%34%7%
144
January1st to 15thNight
15%8%19%30%20%5%
780
16th to endNight
15%8%16%31%21%6%
832
February1st to 15thNight
13%6%20%37%17%4
764
16th to endNight
10%11%26%31%16%2
684
March1st to 15thNight
11%9%23%34%17%4
780
16th to endNight
10%13%25%32%14%3
832
April1st to 15thNight
12%15%24%29%14%2
704
16th to endNight
10%10%23%34%16%3
579
May1st to 15thNight
7%7%24%38%19%2
585
16th to endNight
9%6%18%31%27%6%
611
June1st to 15thNight
410%18%39%24%2
585
16th to endNight
25%21%37%28%4
585
July1st to 15thNight
3315%33%40%3
555
16th to endNight
3214%35%41%3
612
August1st to 15thNight
3219%40%30%2
575
16th to endNight
2315%38%34%5%
621
September1st to 15thNight
3314%36%33%8%
747
16th to endNight
7%5%12%30%32%11%
776
October1st to 15thNight
8%6%21%32%24%6%
752
16th to endNight
8%7%16%32%26%7%
768
November1st to 15thNight
11%9%19%29%24%5%
760
16th to endNight
12%9%20%32%18%6%
839
December1st to 15thNight
16%8%22%33%16%2
975
16th to endNight
21%10%21%31%12%1
907
Page generated at 2018-10-09 08:39:15. Version ac04

Copyright 2018 A. Danko


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