Richmound
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Richmound clear sky chart from 2005-11-05 to 2017-09-21.

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
41%
15461
14%
46804
8%
15435
46%
15435
24%
30732

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
30%
895
11%
2685
7%
895
34%
895
17%
1928
January16th to endNight
31%
924
15%
2832
6%
924
40%
924
19%
1968
February1st to 15thNight
40%
698
11%
2288
9%
697
44%
697
19%
1567
February16th to endNight
41%
632
13%
2052
10%
632
46%
632
17%
1459
March1st to 15thNight
37%
720
12%
2057
7%
720
42%
720
23%
1418
March16th to endNight
39%
765
12%
2109
5%
765
44%
765
20%
1497
April1st to 15thNight
32%
539
13%
1727
7%
539
37%
539
19%
1177
April16th to endNight
39%
540
15%
1611
11%
540
43%
540
21%
1104
May1st to 15thNight
49%
539
14%
1440
10%
539
52%
539
31%
939
May16th to endNight
46%
412
9%
1347
7%
411
48%
411
21%
891
June1st to 15thNight
45%
360
2%
1260
2%
360
46%
360
22%
793
June16th to endNight
52%
360
3%
1260
2%
360
53%
360
28%
718
July1st to 15thNight
57%
340
4%
1190
3%
340
60%
340
34%
619
July16th to endNight
63%
376
16%
1239
14%
354
68%
354
43%
579
August1st to 15thNight
65%
533
14%
1526
11%
531
69%
531
41%
855
August16th to endNight
60%
573
25%
1719
19%
573
65%
573
42%
916
September1st to 15thNight
53%
540
20%
1785
18%
540
57%
540
32%
996
September16th to endNight
50%
674
24%
1893
15%
674
57%
674
39%
1088
October1st to 15thNight
41%
660
19%
1980
11%
660
48%
660
27%
1233
October16th to endNight
42%
746
17%
2239
9%
746
49%
746
25%
1440
November1st to 15thNight
32%
875
18%
2450
8%
875
41%
875
24%
1637
November16th to endNight
29%
900
14%
2535
7%
900
35%
900
21%
1793
December1st to 15thNight
29%
900
8%
2700
4%
900
32%
900
15%
2063
December16th to endNight
31%
960
13%
2880
5%
960
38%
960
18%
2054

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%36%5%35%5%5%7%38%
48101
Night
8%8%36%6%35%5%5%8%38%
46950
Cloud CoverDay
10%7%36%5%35%5%5%7%38%
48102
Night
8%7%36%6%35%5%5%8%38%
46952
TransparencyDay
43%5%16%23%8%1
47752
Night
43%5%16%22%10%1
46804
SeeingDay
14%6%26%29%19%4
6113
Night
12%7%29%33%15%1
15473

By Month

Percentage Cloud Cover NW (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
8%11%5%9%7%5%7%446%30%
1253
16th to endDay
39%5%10%9%5%7%5%6%8%28%
1400
February1st to 15thDay
8%12%5%9%7%45%46%7%27%
1575
16th to endDay
6%14%7%9%7%5%46%5%6%25%
1422
March1st to 15thDay
5%9%48%9%5%5%5%6%9%30%
1899
16th to endDay
9%13%5%8%6%35%6%6%8%26%
2114
April1st to 15thDay
11%9%46%6%46%6%6%8%31%
2219
16th to endDay
15%9%47%5%24447%34%
2349
May1st to 15thDay
13%7%35%5%44445%40%
2511
16th to endDay
20%8%36%435%5%47%30%
2766
June1st to 15thDay
18%6%35%6%35%45%8%31%
2700
16th to endDay
12%424435%5%6%9%40%
2700
July1st to 15thDay
6%414425%5%7%9%47%
2700
16th to endDay
6%21332345%8%57%
2846
August1st to 15thDay
8%315%43445%8%49%
2424
16th to endDay
7%21332345%8%56%
2483
September1st to 15thDay
13%5%23423345%50%
2175
16th to endDay
10%41332346%8%50%
1858
October1st to 15thDay
11%8%36%5%25%35%6%41%
1650
16th to endDay
8%8%25%5%45%5%5%8%39%
1620
November1st to 15thDay
6%9%5%7%5%445%6%8%37%
1408
16th to endDay
9%9%5%8%7%45%447%33%
1425
December1st to 15thDay
8%12%6%10%9%5%6%5%5%7%22%
1260
16th to endDay
5%12%5%10%8%36%5%6%7%27%
1344
January1st to 15thNight
6%9%5%8%7%5%6%6%6%8%29%
2685
16th to endNight
5%8%48%8%5%6%5%6%8%32%
2832
February1st to 15thNight
5%10%5%8%7%45%5%6%8%32%
2277
16th to endNight
6%11%5%9%7%36%5%5%8%29%
2052
March1st to 15thNight
7%6%38%7%46%6%5%9%34%
2057
16th to endNight
8%10%47%6%346%7%9%30%
2106
April1st to 15thNight
12%8%46%5%36%45%8%32%
1727
16th to endNight
13%9%36%5%35%45%7%35%
1611
May1st to 15thNight
14%6%2443445%7%42%
1439
16th to endNight
15%9%25%5%35%45%7%35%
1347
June1st to 15thNight
17%424335%6%5%8%38%
1260
16th to endNight
10%325%5%335%5%8%47%
1260
July1st to 15thNight
6%2145%3346%10%52%
1260
16th to endNight
41123146%6%7%59%
1323
August1st to 15thNight
6%334245%7%9%51%
1533
16th to endNight
6%313324348%56%
1719
September1st to 15thNight
11%5%15%423345%52%
1785
16th to endNight
8%42433346%8%51%
1893
October1st to 15thNight
9%6%36%5%3446%8%41%
1980
16th to endNight
8%8%35%5%35%5%5%7%40%
2239
November1st to 15thNight
8%8%46%435%46%7%41%
2450
16th to endNight
7%10%48%7%45%45%6%35%
2535
December1st to 15thNight
6%13%7%11%9%35%5%47%25%
2700
16th to endNight
5%11%5%8%9%46%5%5%7%30%
2880

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
9%11%49%7%47%446%30%
1253
16th to endDay
39%5%10%8%5%7%5%6%8%28%
1400
February1st to 15thDay
8%12%5%10%7%45%5%6%7%27%
1575
16th to endDay
6%14%7%9%7%446%5%5%26%
1422
March1st to 15thDay
5%9%48%9%46%46%9%30%
1899
16th to endDay
10%12%5%7%6%45%6%6%7%26%
2115
April1st to 15thDay
11%9%36%6%45%6%6%8%31%
2219
16th to endDay
16%9%46%5%24447%33%
2349
May1st to 15thDay
12%8%26%5%44446%40%
2511
16th to endDay
20%8%36%5%25%45%7%30%
2766
June1st to 15thDay
19%5%25%6%26%46%8%32%
2700
16th to endDay
12%4245%35%5%6%8%41%
2700
July1st to 15thDay
7%3144245%7%9%48%
2700
16th to endDay
6%21232346%7%58%
2846
August1st to 15thDay
8%31443345%8%50%
2424
16th to endDay
7%21332345%8%56%
2483
September1st to 15thDay
13%5%24323335%51%
2175
16th to endDay
11%42322346%8%50%
1858
October1st to 15thDay
11%7%36%42435%7%42%
1650
16th to endDay
8%8%25%5%35%5%6%8%39%
1620
November1st to 15thDay
6%9%5%7%5%3446%7%38%
1408
16th to endDay
9%10%48%7%35%5%48%33%
1425
December1st to 15thDay
8%12%6%10%9%5%7%5%5%7%22%
1260
16th to endDay
5%12%5%10%8%36%5%6%7%27%
1344
January1st to 15thNight
7%9%48%8%46%6%6%8%29%
2685
16th to endNight
5%8%48%7%5%6%6%6%8%32%
2832
February1st to 15thNight
6%10%49%7%45%5%6%8%32%
2277
16th to endNight
6%11%6%9%7%35%46%7%30%
2052
March1st to 15thNight
7%7%37%7%46%6%6%9%35%
2057
16th to endNight
8%10%47%6%35%6%7%8%31%
2109
April1st to 15thNight
12%8%36%5%45%6%5%8%33%
1727
16th to endNight
13%8%36%5%35%45%7%35%
1611
May1st to 15thNight
14%7%2442445%8%42%
1439
16th to endNight
17%8%25%435%45%7%35%
1346
June1st to 15thNight
17%324426%5%5%8%38%
1260
16th to endNight
11%3244335%5%8%47%
1260
July1st to 15thNight
6%21343347%10%52%
1260
16th to endNight
4123145%6%7%60%
1323
August1st to 15thNight
7%2134245%7%10%51%
1533
16th to endNight
6%323323349%56%
1719
September1st to 15thNight
11%5%23423345%52%
1785
16th to endNight
9%4144235%5%8%51%
1893
October1st to 15thNight
10%6%36%5%3436%8%41%
1980
16th to endNight
9%7%35%5%35%5%5%7%40%
2239
November1st to 15thNight
9%8%45%435%45%7%41%
2450
16th to endNight
7%10%48%6%45%45%6%35%
2535
December1st to 15thNight
6%13%6%10%8%45%5%47%25%
2700
16th to endNight
5%10%5%8%8%46%5%6%7%30%
2880

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
55%7%16%16%4
1253
16th to endDay
51%7%18%15%5%1
1400
February1st to 15thDay
55%416%18%4
1575
16th to endDay
56%5%14%14%7%
1422
March1st to 15thDay
49%8%22%15%4
1899
16th to endDay
53%9%15%18%3
2115
April1st to 15thDay
48%6%13%21%8%
2219
16th to endDay
50%414%22%5%1
2349
May1st to 15thDay
45%315%24%10%
2511
16th to endDay
52%5%13%20%7%
2771
June1st to 15thDay
48%6%14%22%7%1
2700
16th to endDay
38%5%20%26%8%
2700
July1st to 15thDay
29%6%19%30%12%1
2541
16th to endDay
23%5%17%35%15%2
2667
August1st to 15thDay
31%5%21%29%10%1
2407
16th to endDay
24%416%34%17%2
2483
September1st to 15thDay
35%313%26%17%4
2175
16th to endDay
30%5%14%31%16%2
1858
October1st to 15thDay
42%418%25%8%
1650
16th to endDay
40%6%19%24%8%
1620
November1st to 15thDay
43%6%18%25%5%
1408
16th to endDay
50%6%17%19%5%
1425
December1st to 15thDay
60%6%16%14%1
1260
16th to endDay
53%418%19%4
1344
January1st to 15thNight
50%6%19%18%4
2685
16th to endNight
48%5%17%19%6%1
2832
February1st to 15thNight
48%5%17%19%8%
2288
16th to endNight
51%5%14%19%7%
2052
March1st to 15thNight
44%7%21%19%7%
2057
16th to endNight
47%7%16%20%6%
2109
April1st to 15thNight
47%7%13%21%9%1
1727
16th to endNight
47%5%11%19%12%2
1611
May1st to 15thNight
39%411%26%16%
1440
16th to endNight
46%415%20%12%
1347
June1st to 15thNight
42%5%17%25%8%1
1260
16th to endNight
34%5%17%28%13%1
1260
July1st to 15thNight
27%5%18%27%17%2
1190
16th to endNight
20%5%16%33%19%4
1239
August1st to 15thNight
25%6%19%32%12%2
1526
16th to endNight
26%311%30%24%3
1719
September1st to 15thNight
33%310%24%18%8%
1785
16th to endNight
29%414%28%19%3
1893
October1st to 15thNight
39%417%25%11%1
1980
16th to endNight
40%5%17%25%8%
2239
November1st to 15thNight
41%7%18%23%9%
2450
16th to endNight
48%5%20%16%8%
2535
December1st to 15thNight
57%6%18%14%3
2700
16th to endNight
51%5%17%19%5%
2880

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
5%6%23%31%23%10%
60
16th to endDay
7%443%21%13%9%
66
February1st to 15thDay
16%5%32%34%6%4
90
16th to endDay
14%8%28%30%9%7%
81
March1st to 15thDay
12%12%41%26%7%
231
16th to endDay
15%9%35%28%9%1
288
April1st to 15thDay
13%16%34%26%8%1
269
16th to endDay
24%7%23%25%15%2
279
May1st to 15thDay
14%5%26%30%19%4
468
16th to endDay
21%422%24%18%8%
517
June1st to 15thDay
18%7%25%27%17%3
495
16th to endDay
13%6%27%28%21%4
495
July1st to 15thDay
10%217%34%29%5%
475
16th to endDay
7%426%32%23%4
515
August1st to 15thDay
9%321%26%29%10%
393
16th to endDay
8%418%32%30%6%
332
September1st to 15thDay
17%6%20%32%18%5%
315
16th to endDay
11%7%26%30%19%4
257
October1st to 15thDay
27%5%25%27%12%1
90
16th to endDay
13%321%29%29%3
96
November1st to 15thDay
11%8%35%30%14%
90
16th to endDay
9%9%34%25%14%6%
87
December1st to 15thDay
5%13%36%25%13%6%
60
16th to endDay
17%7%31%28%12%3
64
January1st to 15thNight
12%12%34%27%12%2
900
16th to endNight
9%11%36%30%10%
924
February1st to 15thNight
9%8%29%34%14%2
704
16th to endNight
10%7%26%35%16%3
632
March1st to 15thNight
8%7%35%35%11%1
720
16th to endNight
13%8%27%37%11%1
765
April1st to 15thNight
16%8%31%31%10%1
539
16th to endNight
17%6%25%33%15%2
540
May1st to 15thNight
17%5%22%33%20%1
540
16th to endNight
18%6%19%32%18%3
412
June1st to 15thNight
19%423%32%18%1
360
16th to endNight
11%424%40%17%1
360
July1st to 15thNight
9%320%44%20%
340
16th to endNight
5%422%42%23%1
376
August1st to 15thNight
8%218%38%30%2
533
16th to endNight
8%421%36%28%1
573
September1st to 15thNight
14%421%35%22%2
540
16th to endNight
10%428%36%18%2
674
October1st to 15thNight
12%5%32%30%16%2
660
16th to endNight
14%7%28%36%12%
746
November1st to 15thNight
12%11%34%31%8%1
875
16th to endNight
12%8%37%29%10%
900
December1st to 15thNight
13%7%33%29%14%2
900
16th to endNight
10%9%32%29%13%4
960
Page generated at 2017-09-22 05:35:33. Version ac04

Copyright 2017 A. Danko


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