Mountain Home
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mountain Home clear sky chart from 2005-11-05 to 2017-09-24.

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
44%
15759
24%
47016
16%
15712
53%
15712
31%
28007

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
25%
900
26%
2327
8%
895
37%
895
26%
1496
January16th to endNight
26%
960
27%
2496
8%
960
38%
960
32%
1548
February1st to 15thNight
25%
877
20%
2285
6%
873
34%
873
28%
1488
February16th to endNight
21%
631
25%
1893
7%
631
35%
631
27%
1120
March1st to 15thNight
30%
540
21%
1980
14%
540
39%
540
21%
1231
March16th to endNight
33%
576
16%
2104
13%
576
39%
576
20%
1349
April1st to 15thNight
30%
539
24%
1797
12%
539
47%
539
28%
1019
April16th to endNight
34%
540
22%
1800
15%
540
48%
540
29%
1060
May1st to 15thNight
43%
540
19%
1716
15%
540
51%
540
27%
1065
May16th to endNight
50%
563
20%
1591
14%
561
56%
561
32%
984
June1st to 15thNight
71%
540
25%
1440
20%
540
74%
540
49%
777
June16th to endNight
69%
540
27%
1440
20%
540
73%
540
45%
809
July1st to 15thNight
70%
510
18%
1491
18%
510
72%
510
35%
895
July16th to endNight
82%
564
25%
1594
27%
531
84%
531
44%
843
August1st to 15thNight
78%
539
24%
1637
28%
536
79%
536
40%
889
August16th to endNight
74%
573
23%
1910
27%
573
77%
573
36%
1055
September1st to 15thNight
67%
540
27%
1800
28%
540
70%
540
32%
1028
September16th to endNight
62%
577
31%
1897
26%
577
67%
577
35%
1044
October1st to 15thNight
56%
660
30%
1980
23%
660
61%
660
38%
1112
October16th to endNight
45%
704
32%
2112
20%
704
55%
704
37%
1177
November1st to 15thNight
43%
700
32%
2139
18%
700
56%
700
36%
1163
November16th to endNight
34%
786
25%
2406
15%
786
45%
786
27%
1471
December1st to 15thNight
33%
900
21%
2520
9%
900
42%
900
28%
1610
December16th to endNight
28%
960
22%
2661
9%
960
39%
960
23%
1774

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
12%5%25%42445%7%44%
47898
Night
11%5%24423446%49%
47212
TransparencyDay
38%5%11%24%16%3
47598
Night
34%411%25%19%4
47017
SeeingDay
13%6%22%27%22%7%
5807
Night
15%8%26%30%16%1
15759

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 15thDay
16%5%14423325%50%
1611
16th to endDay
14%7%24323335%48%
1728
February1st to 15thDay
14%6%36%42333446%
1578
16th to endDay
12%9%345%2345%5%41%
1589
March1st to 15thDay
18%7%34323345%43%
1980
16th to endDay
19%7%26%5%33345%38%
2117
April1st to 15thDay
12%6%35%5%24345%46%
2151
16th to endDay
17%7%25%43445%6%37%
2160
May1st to 15thDay
15%5%36%5%25%45%6%39%
2232
16th to endDay
10%6%35%6%35%46%8%37%
2520
June1st to 15thDay
7%4145%36%5%6%9%45%
2520
16th to endDay
5%3245%45%6%7%9%46%
2520
July1st to 15thDay
7%437%6%37%7%7%9%34%
2374
16th to endDay
5%314436%6%7%11%44%
2466
August1st to 15thDay
9%415%435%5%7%10%42%
2313
16th to endDay
7%425%5%26%6%7%8%43%
2292
September1st to 15thDay
13%5%244345%6%6%45%
2160
16th to endDay
12%5%1442445%6%47%
1907
October1st to 15thDay
13%415%323335%52%
1650
16th to endDay
14%413322246%55%
1760
November1st to 15thDay
10%5%14322435%56%
1716
16th to endDay
18%5%25%213135%48%
1554
December1st to 15thDay
17%6%24423346%44%
1440
16th to endDay
16%8%36%42444441%
1560
January1st to 15thNight
16%5%24423335%48%
2327
16th to endNight
12%6%3442333452%
2496
February1st to 15thNight
13%6%25%424345%46%
2275
16th to endNight
12%6%23423336%49%
1893
March1st to 15thNight
18%7%24323336%43%
1980
16th to endNight
18%6%25%5%2435%5%39%
2104
April1st to 15thNight
9%5%24424446%52%
1797
16th to endNight
14%41442345%7%46%
1800
May1st to 15thNight
13%5%235%24347%47%
1715
16th to endNight
10%5%2432446%8%46%
1590
June1st to 15thNight
5%21331345%11%57%
1440
16th to endNight
422342445%9%55%
1440
July1st to 15thNight
43246%36%5%6%10%46%
1581
16th to endNight
32133245%6%8%57%
1702
August1st to 15thNight
44134245%6%9%53%
1647
16th to endNight
4424325%5%7%9%49%
1910
September1st to 15thNight
9%42442345%8%50%
1800
16th to endNight
9%424423446%54%
1897
October1st to 15thNight
11%5%1331335%6%54%
1980
16th to endNight
13%31432222458%
2112
November1st to 15thNight
9%423323445%57%
2139
16th to endNight
16%6%33323335%49%
2406
December1st to 15thNight
18%6%24313336%45%
2520
16th to endNight
19%7%24423335%43%
2661

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
38%28%28%17%3
1612
16th to endDay
37%210%29%16%3
1728
February1st to 15thDay
41%311%25%13%2
1579
16th to endDay
43%49%24%14%3
1589
March1st to 15thDay
42%39%22%16%5%
1980
16th to endDay
47%311%22%12%1
2119
April1st to 15thDay
39%49%25%19%2
2151
16th to endDay
45%411%20%14%3
2160
May1st to 15thDay
44%6%11%21%15%1
2232
16th to endDay
44%7%13%22%10%2
2524
June1st to 15thDay
34%7%14%24%17%1
2520
16th to endDay
31%6%15%27%16%2
2520
July1st to 15thDay
41%7%13%23%11%1
2235
16th to endDay
30%8%16%29%12%1
2311
August1st to 15thDay
34%7%14%25%16%1
2299
16th to endDay
34%7%14%22%15%5%
2292
September1st to 15thDay
37%6%9%23%16%6%
2160
16th to endDay
35%5%7%25%23%2
1907
October1st to 15thDay
34%5%7%24%22%5%
1650
16th to endDay
30%36%29%22%6%
1760
November1st to 15thDay
31%38%26%22%8%
1716
16th to endDay
39%28%22%23%2
1554
December1st to 15thDay
41%311%24%16%1
1440
16th to endDay
45%410%21%15%3
1560
January1st to 15thNight
39%38%24%21%2
2327
16th to endNight
35%210%29%18%3
2496
February1st to 15thNight
39%310%26%16%3
2285
16th to endNight
34%412%26%17%4
1893
March1st to 15thNight
42%410%19%17%5%
1980
16th to endNight
45%310%22%15%1
2104
April1st to 15thNight
33%311%24%21%5%
1797
16th to endNight
34%5%12%27%16%3
1800
May1st to 15thNight
37%6%12%22%17%3
1716
16th to endNight
33%7%18%22%15%2
1592
June1st to 15thNight
21%5%15%34%22%1
1440
16th to endNight
24%6%14%28%21%5%
1440
July1st to 15thNight
31%7%14%27%17%2
1491
16th to endNight
21%7%17%32%18%1
1594
August1st to 15thNight
24%7%15%31%19%2
1637
16th to endNight
28%7%17%23%18%5%
1910
September1st to 15thNight
32%5%8%27%17%8%
1800
16th to endNight
30%5%9%20%29%4
1897
October1st to 15thNight
29%410%23%25%6%
1980
16th to endNight
30%27%25%25%8%
2112
November1st to 15thNight
28%38%26%24%8%
2139
16th to endNight
38%37%23%22%4
2406
December1st to 15thNight
40%312%23%16%3
2520
16th to endNight
44%310%22%16%3
2661

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
28%17%36%13%3
90
16th to endDay
22%34%28%10%4
96
February1st to 15thDay
17%14%51%13%21
90
16th to endDay
19%27%30%16%41
81
March1st to 15thDay
32%21%28%14%3
90
16th to endDay
16%21%38%19%3
103
April1st to 15thDay
15%15%32%25%10%
270
16th to endDay
23%10%32%21%9%2
270
May1st to 15thDay
17%12%31%21%15%1
369
16th to endDay
13%6%35%27%13%4
517
June1st to 15thDay
10%218%34%25%8%
495
16th to endDay
7%221%35%26%6%
495
July1st to 15thDay
9%116%36%27%8%
475
16th to endDay
5%7%25%40%20%
515
August1st to 15thDay
12%9%30%36%11%
466
16th to endDay
11%10%29%35%12%
332
September1st to 15thDay
10%411%24%36%13%
315
16th to endDay
13%312%29%29%10%
186
October1st to 15thDay
11%7%34%27%17%1
90
16th to endDay
20%33%33%9%3
96
November1st to 15thDay
11%432%28%18%4
90
16th to endDay
35%21%20%14%8%
90
December1st to 15thDay
22%14%34%15%6%6%
90
16th to endDay
22%20%34%19%2
96
January1st to 15thNight
22%16%33%22%4
900
16th to endNight
17%15%37%27%2
960
February1st to 15thNight
19%13%37%27%2
877
16th to endNight
19%16%40%21%2
631
March1st to 15thNight
22%11%31%31%2
540
16th to endNight
20%11%31%29%6%
576
April1st to 15thNight
12%14%38%27%6%
539
16th to endNight
14%10%36%30%7%
540
May1st to 15thNight
15%7%29%35%11%
540
16th to endNight
12%5%25%34%20%2
563
June1st to 15thNight
7%214%42%31%2
540
16th to endNight
6%115%40%32%3
540
July1st to 15thNight
5%212%40%34%4
510
16th to endNight
45%32%47%9%
564
August1st to 15thNight
5%8%32%44%8%
539
16th to endNight
7%18%37%39%6%
573
September1st to 15thNight
10%212%29%40%4
540
16th to endNight
11%315%31%31%5%
577
October1st to 15thNight
14%321%31%24%3
660
16th to endNight
15%7%28%31%15%
704
November1st to 15thNight
12%11%30%30%15%
700
16th to endNight
22%10%29%26%11%
786
December1st to 15thNight
23%11%28%29%6%
900
16th to endNight
23%15%29%27%4
960
Page generated at 2017-09-25 08:02:19. Version ac04

Copyright 2017 A. Danko


Mountain Home Clear Sky Chart | Charts Home