Rexburg
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rexburg clear sky chart from 2005-11-05 to 2017-10-06.

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%
15580
18%
46969
15%
15541
55%
15541
27%
30035

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
39%
775
8%
2565
8%
775
40%
775
13%
1970
January16th to endNight
40%
768
10%
2526
10%
768
42%
768
14%
1876
February1st to 15thNight
39%
699
8%
2288
8%
697
40%
697
15%
1692
February16th to endNight
38%
632
11%
1955
10%
632
42%
632
17%
1416
March1st to 15thNight
47%
720
12%
2034
10%
720
49%
720
22%
1438
March16th to endNight
43%
768
13%
2112
9%
768
46%
768
22%
1494
April1st to 15thNight
47%
623
15%
1811
10%
623
51%
623
26%
1200
April16th to endNight
46%
540
21%
1620
16%
540
49%
540
27%
1026
May1st to 15thNight
52%
539
18%
1619
15%
539
55%
539
32%
969
May16th to endNight
54%
562
16%
1549
14%
561
57%
561
31%
997
June1st to 15thNight
58%
396
16%
1296
15%
396
63%
396
32%
744
June16th to endNight
72%
360
28%
1260
29%
360
80%
360
53%
538
July1st to 15thNight
83%
340
25%
1230
31%
340
88%
340
54%
508
July16th to endNight
79%
511
29%
1540
31%
478
82%
478
58%
671
August1st to 15thNight
78%
539
28%
1611
26%
536
79%
536
51%
789
August16th to endNight
76%
573
38%
1719
31%
573
78%
573
56%
809
September1st to 15thNight
73%
648
29%
1896
24%
648
78%
648
50%
959
September16th to endNight
69%
716
33%
1980
26%
716
73%
716
46%
1089
October1st to 15thNight
60%
684
24%
2004
20%
684
63%
684
36%
1164
October16th to endNight
59%
704
23%
2163
20%
704
63%
704
32%
1306
November1st to 15thNight
50%
723
19%
2298
18%
723
52%
723
26%
1456
November16th to endNight
46%
900
13%
2520
10%
900
48%
900
23%
1743
December1st to 15thNight
37%
900
6%
2520
4%
900
39%
900
15%
1963
December16th to endNight
36%
960
8%
2853
6%
960
38%
960
13%
2218

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
10%7%35%424446%47%
48234
Night
11%9%35%423446%43%
47146
TransparencyDay
37%412%21%16%8%
47910
Night
41%5%13%20%13%6%
46970
SeeingDay
12%8%23%28%20%6%
5883
Night
15%417%38%21%2
15592

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
18%14%5%8%5%23345%27%
1382
16th to endDay
18%14%5%8%42433330%
1695
February1st to 15thDay
17%12%47%5%2444431%
1575
16th to endDay
10%14%5%8%6%3435%6%30%
1518
March1st to 15thDay
9%11%47%5%35%447%34%
1926
16th to endDay
13%11%5%7%6%345%46%31%
2112
April1st to 15thDay
10%11%35%5%4346%8%35%
2135
16th to endDay
9%8%35%5%35%446%42%
2340
May1st to 15thDay
8%6%245%24447%48%
2331
16th to endDay
12%7%36%5%3445%8%38%
2564
June1st to 15thDay
10%425%6%2446%8%44%
2661
16th to endDay
3212223346%68%
2700
July1st to 15thDay
211322335%7%66%
2654
16th to endDay
3212223346%67%
2520
August1st to 15thDay
321231245%7%65%
2340
16th to endDay
3212323446%65%
2483
September1st to 15thDay
5%312323335%65%
2061
16th to endDay
8%312313346%60%
1980
October1st to 15thDay
13%5%235%2445%5%47%
1753
16th to endDay
12%5%245%245%45%47%
1708
November1st to 15thDay
14%9%34424335%42%
1548
16th to endDay
14%12%45%5%24445%37%
1440
December1st to 15thDay
17%14%6%9%7%3433425%
1440
16th to endDay
20%13%6%8%5%3343425%
1368
January1st to 15thNight
19%14%49%5%23235%28%
2565
16th to endNight
18%16%6%6%42333331%
2526
February1st to 15thNight
16%16%47%5%22345%29%
2277
16th to endNight
12%14%5%8%5%25%5%46%29%
1955
March1st to 15thNight
10%12%36%5%345%5%8%33%
2034
16th to endNight
13%10%47%5%2445%7%33%
2112
April1st to 15thNight
11%8%36%43446%9%37%
1811
16th to endNight
11%7%25%5%2435%7%43%
1620
May1st to 15thNight
7%6%25%43445%7%47%
1619
16th to endNight
10%5%25%5%25%5%6%7%42%
1548
June1st to 15thNight
8%423435%5%6%8%47%
1296
16th to endNight
31222335%6%68%
1260
July1st to 15thNight
1112335%6%10%63%
1303
16th to endNight
212223446%68%
1647
August1st to 15thNight
311232445%8%62%
1620
16th to endNight
3212212447%67%
1719
September1st to 15thNight
5%21232235%5%64%
1896
16th to endNight
8%412322346%59%
1980
October1st to 15thNight
11%5%235%24345%52%
2004
16th to endNight
13%6%24423446%48%
2163
November1st to 15thNight
15%9%24323346%43%
2298
16th to endNight
13%11%46%5%33445%38%
2520
December1st to 15thNight
18%13%49%6%3443427%
2520
16th to endNight
20%17%5%7%5%2333426%
2853

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
58%7%17%10%5%
1382
16th to endDay
58%6%14%14%41
1695
February1st to 15thDay
55%7%16%16%4
1575
16th to endDay
51%7%16%17%4
1518
March1st to 15thDay
47%7%18%20%41
1926
16th to endDay
53%5%13%20%6%
2112
April1st to 15thDay
44%6%16%21%10%
2135
16th to endDay
41%412%28%12%1
2340
May1st to 15thDay
35%48%31%17%2
2331
16th to endDay
42%5%13%25%10%1
2567
June1st to 15thDay
36%5%12%25%16%3
2661
16th to endDay
17%26%21%33%18%
2700
July1st to 15thDay
17%35%19%31%23%
2498
16th to endDay
17%2415%25%34%
2364
August1st to 15thDay
17%35%16%29%25%
2325
16th to endDay
18%35%20%30%21%
2483
September1st to 15thDay
21%28%19%32%15%
2061
16th to endDay
24%39%29%24%8%
1980
October1st to 15thDay
36%414%30%9%3
1753
16th to endDay
37%417%24%14%
1708
November1st to 15thDay
44%418%21%8%2
1548
16th to endDay
48%421%18%5%1
1440
December1st to 15thDay
61%6%12%15%2
1440
16th to endDay
61%5%15%12%3
1368
January1st to 15thNight
59%6%15%12%4
2565
16th to endNight
57%5%15%16%31
2526
February1st to 15thNight
56%5%17%15%4
2288
16th to endNight
54%5%16%18%41
1955
March1st to 15thNight
47%6%17%20%6%1
2034
16th to endNight
48%6%14%23%6%1
2112
April1st to 15thNight
42%5%17%23%10%
1811
16th to endNight
39%5%10%28%15%
1620
May1st to 15thNight
35%49%29%18%2
1620
16th to endNight
38%5%14%24%14%2
1549
June1st to 15thNight
31%6%13%24%20%3
1296
16th to endNight
15%36%18%34%21%
1260
July1st to 15thNight
15%36%20%26%27%
1230
16th to endNight
15%25%13%25%37%
1540
August1st to 15thNight
18%46%18%23%28%
1611
16th to endNight
17%26%18%30%25%
1719
September1st to 15thNight
20%47%17%31%19%
1896
16th to endNight
25%38%25%27%8%
1980
October1st to 15thNight
32%314%30%14%3
2004
16th to endNight
36%413%27%17%1
2163
November1st to 15thNight
41%5%15%26%8%2
2298
16th to endNight
47%419%19%8%1
2520
December1st to 15thNight
59%6%18%12%3
2520
16th to endNight
61%415%13%31
2853

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%115%21%28%11%
60
16th to endDay
30%112%30%21%3
91
February1st to 15thDay
27%325%13%23%6%
90
16th to endDay
18%11%33%25%8%2
177
March1st to 15thDay
15%19%31%25%7%
270
16th to endDay
21%19%32%19%6%
288
April1st to 15thDay
16%17%26%24%13%2
269
16th to endDay
18%14%27%25%11%1
270
May1st to 15thDay
11%11%30%25%15%5%
288
16th to endDay
16%6%20%25%22%8%
465
June1st to 15thDay
10%11%22%29%21%5%
495
16th to endDay
48%24%28%27%6%
495
July1st to 15thDay
45%17%34%29%8%
432
16th to endDay
3425%40%19%6%
327
August1st to 15thDay
4328%32%26%4
315
16th to endDay
6%418%32%23%14%
332
September1st to 15thDay
7%6%22%28%22%12%
315
16th to endDay
12%7%20%26%21%10%
315
October1st to 15thDay
17%5%19%24%29%4
155
16th to endDay
25%9%11%21%22%9%
96
November1st to 15thDay
18%28%27%18%23%
90
16th to endDay
25%6%23%35%7%1
90
December1st to 15thDay
31%326%28%10%
90
16th to endDay
27%113%30%17%8%
68
January1st to 15thNight
25%5%13%36%17%1
780
16th to endNight
24%414%34%19%2
768
February1st to 15thNight
23%318%37%15%1
704
16th to endNight
15%7%23%38%11%3
632
March1st to 15thNight
15%6%22%39%14%1
720
16th to endNight
17%7%24%36%12%1
768
April1st to 15thNight
15%6%23%36%16%1
623
16th to endNight
15%5%27%35%15%
540
May1st to 15thNight
7%6%25%37%21%1
540
16th to endNight
12%419%37%22%2
563
June1st to 15thNight
10%419%40%23%1
396
16th to endNight
4217%44%27%4
360
July1st to 15thNight
210%47%37%2
340
16th to endNight
211%45%36%3
511
August1st to 15thNight
4110%46%35%2
539
16th to endNight
4113%43%33%3
573
September1st to 15thNight
6%114%37%32%6%
648
16th to endNight
10%213%32%32%8%
716
October1st to 15thNight
14%315%38%25%2
684
16th to endNight
14%315%39%22%5%
704
November1st to 15thNight
19%419%34%20%1
723
16th to endNight
17%6%19%36%17%2
900
December1st to 15thNight
23%6%18%38%12%1
900
16th to endNight
28%5%15%35%13%1
960
Page generated at 2017-10-07 12:07:56. Version ac04

Copyright 2017 A. Danko


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