Rimrock Meadows
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rimrock Meadows clear sky chart from 2005-11-05 to 2017-04-24.

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
50%
14142
16%
45632
13%
14114
55%
14114
25%
28998

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
34%
717
7%
2506
6%
716
37%
716
11%
1965
January16th to endNight
39%
768
6%
2688
5%
768
41%
768
11%
2101
February1st to 15thNight
41%
699
9%
2332
6%
696
47%
696
16%
1691
February16th to endNight
44%
632
15%
1943
11%
632
50%
632
20%
1354
March1st to 15thNight
46%
720
12%
2154
10%
720
50%
720
22%
1489
March16th to endNight
43%
768
15%
2003
6%
768
48%
768
25%
1398
April1st to 15thNight
45%
719
17%
1799
7%
719
49%
719
29%
1230
April16th to endNight
48%
564
19%
1608
10%
564
55%
564
34%
959
May1st to 15thNight
48%
329
24%
1319
26%
329
60%
329
32%
650
May16th to endNight
58%
342
13%
1368
17%
342
63%
342
24%
797
June1st to 15thNight
48%
330
13%
1320
9%
330
56%
330
30%
678
June16th to endNight
51%
330
13%
1320
11%
330
59%
330
37%
609
July1st to 15thNight
66%
310
18%
1240
19%
310
75%
310
52%
463
July16th to endNight
70%
348
25%
1304
32%
326
82%
326
61%
447
August1st to 15thNight
78%
330
34%
1312
42%
328
85%
328
62%
453
August16th to endNight
71%
648
31%
1698
20%
648
75%
648
59%
859
September1st to 15thNight
68%
660
32%
1650
15%
660
74%
660
63%
828
September16th to endNight
65%
656
30%
1776
23%
656
68%
656
46%
975
October1st to 15thNight
54%
660
21%
1980
19%
660
60%
660
32%
1178
October16th to endNight
54%
704
18%
2241
16%
704
60%
704
24%
1470
November1st to 15thNight
46%
700
12%
2343
9%
700
51%
700
19%
1603
November16th to endNight
39%
720
11%
2520
7%
720
45%
720
13%
1873
December1st to 15thNight
41%
720
10%
2520
8%
720
45%
720
13%
1862
December16th to endNight
36%
768
10%
2688
6%
768
41%
768
12%
2066

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
7%7%35%5%3445%7%45%
45994
Night
8%7%36%5%3445%7%42%
45800
Cloud CoverDay
8%6%35%5%2445%6%46%
45994
Night
9%7%36%5%3445%7%42%
45804
TransparencyDay
37%6%12%22%16%4
45665
Night
40%6%13%21%14%4
45633
SeeingDay
10%8%23%29%21%7%
4829
Night
12%422%35%21%3
14152

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
14%16%7%11%6%34446%19%
1432
16th to endDay
13%16%7%9%6%345%5%421%
1536
February1st to 15thDay
12%15%5%10%7%34446%25%
1531
16th to endDay
9%10%36%6%345%7%8%34%
1530
March1st to 15thDay
10%10%47%425%6%6%8%31%
1803
16th to endDay
8%8%36%6%46%6%8%8%33%
2220
April1st to 15thDay
8%6%36%6%35%6%6%9%37%
2149
16th to endDay
5%5%26%6%35%5%7%8%44%
2209
May1st to 15thDay
5%4244245%6%9%50%
2301
16th to endDay
8%5%26%6%46%5%6%8%37%
2391
June1st to 15thDay
8%424435%45%8%47%
2310
16th to endDay
6%426%42445%8%50%
2310
July1st to 15thDay
11232324470%
2310
16th to endDay
1212112335%74%
2461
August1st to 15thDay
2112212345%70%
2310
16th to endDay
222313436%67%
2148
September1st to 15thDay
223213345%69%
1980
16th to endDay
6%3145%235%46%56%
1851
October1st to 15thDay
9%5%2443347%6%47%
1650
16th to endDay
12%6%25%5%3445%8%40%
1631
November1st to 15thDay
11%9%38%6%45%5%5%7%32%
1515
16th to endDay
12%15%5%8%6%35%46%7%24%
1440
December1st to 15thDay
11%13%5%10%7%36%5%45%25%
1440
16th to endDay
17%14%7%8%5%34346%23%
1536
January1st to 15thNight
14%15%6%10%6%25%447%22%
2506
16th to endNight
11%13%6%12%7%4445%6%23%
2688
February1st to 15thNight
12%11%47%5%35%45%7%30%
2320
16th to endNight
9%9%35%6%35%6%6%8%34%
1943
March1st to 15thNight
9%8%47%6%35%6%7%7%33%
2154
16th to endNight
7%5%37%6%45%6%6%10%36%
1999
April1st to 15thNight
9%7%36%5%25%45%7%42%
1799
16th to endNight
6%5%245%235%6%9%47%
1608
May1st to 15thNight
6%414325%46%7%53%
1319
16th to endNight
7%425%6%36%6%7%8%40%
1368
June1st to 15thNight
6%32442445%6%54%
1320
16th to endNight
421432445%6%58%
1320
July1st to 15thNight
1113212336%72%
1320
16th to endNight
1111223479%
1400
August1st to 15thNight
11112237%76%
1320
16th to endNight
2112323446%68%
1698
September1st to 15thNight
2111113346%70%
1650
16th to endNight
431442345%8%56%
1776
October1st to 15thNight
9%5%25%434446%49%
1980
16th to endNight
9%6%26%6%25%6%6%8%37%
2241
November1st to 15thNight
12%9%46%5%345%5%7%35%
2343
16th to endNight
12%12%5%8%5%35%45%6%29%
2520
December1st to 15thNight
13%9%6%8%7%45%5%6%7%26%
2520
16th to endNight
16%13%5%9%7%33345%26%
2688

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
15%16%5%12%6%26%446%19%
1432
16th to endDay
13%16%7%9%7%345%4421%
1536
February1st to 15thDay
13%14%6%8%6%35%45%5%26%
1531
16th to endDay
9%10%47%6%25%6%6%8%34%
1530
March1st to 15thDay
10%10%47%5%346%6%8%31%
1803
16th to endDay
8%7%36%6%36%6%7%7%34%
2220
April1st to 15thDay
9%6%36%5%36%6%6%7%38%
2149
16th to endDay
5%5%35%5%346%6%8%45%
2209
May1st to 15thDay
5%42343447%8%51%
2301
16th to endDay
8%426%6%46%5%6%7%39%
2391
June1st to 15thDay
9%424425%45%8%48%
2310
16th to endDay
7%426%42445%7%52%
2310
July1st to 15thDay
113313335%70%
2310
16th to endDay
121131224474%
2461
August1st to 15thDay
2212212245%71%
2310
16th to endDay
2212323345%68%
2148
September1st to 15thDay
2212323345%69%
1980
16th to endDay
6%314434447%56%
1851
October1st to 15thDay
9%6%244245%5%7%47%
1650
16th to endDay
12%6%25%5%25%45%8%40%
1631
November1st to 15thDay
12%7%5%7%7%445%5%6%33%
1515
16th to endDay
12%15%5%9%6%35%5%47%25%
1440
December1st to 15thDay
11%13%6%9%7%35%6%5%5%26%
1440
16th to endDay
17%14%7%8%6%34346%22%
1536
January1st to 15thNight
15%16%5%10%6%3435%7%22%
2506
16th to endNight
12%13%6%11%8%35%436%23%
2688
February1st to 15thNight
12%11%47%6%35%46%7%30%
2320
16th to endNight
9%8%46%6%35%6%7%7%34%
1943
March1st to 15thNight
10%8%38%6%36%5%7%7%33%
2154
16th to endNight
8%5%36%7%45%6%6%9%36%
2003
April1st to 15thNight
9%7%35%5%35%448%41%
1799
16th to endNight
6%424425%5%7%8%47%
1608
May1st to 15thNight
6%424325%46%7%53%
1319
16th to endNight
7%426%7%35%6%5%9%40%
1368
June1st to 15thNight
7%324425%446%55%
1320
16th to endNight
431432436%6%59%
1320
July1st to 15thNight
1112222335%71%
1320
16th to endNight
11111233478%
1400
August1st to 15thNight
11212327%75%
1320
16th to endNight
2212223445%68%
1698
September1st to 15thNight
2111212346%71%
1650
16th to endNight
431442345%7%57%
1776
October1st to 15thNight
9%5%25%4345%45%49%
1980
16th to endNight
10%6%26%7%345%7%8%37%
2241
November1st to 15thNight
13%8%36%5%35%5%5%7%35%
2343
16th to endNight
12%12%5%7%5%45%45%6%29%
2520
December1st to 15thNight
13%10%5%8%6%35%5%6%7%26%
2520
16th to endNight
17%13%5%9%6%24345%26%
2688

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
66%7%10%11%31
1432
16th to endDay
64%7%14%10%2
1536
February1st to 15thDay
57%9%14%14%4
1531
16th to endDay
43%8%19%21%7%
1530
March1st to 15thDay
47%8%15%22%6%
1803
16th to endDay
45%9%16%20%7%
2220
April1st to 15thDay
41%7%15%22%11%1
2149
16th to endDay
34%7%16%25%13%2
2209
May1st to 15thDay
28%5%10%32%19%3
2301
16th to endDay
40%7%15%22%12%
2395
June1st to 15thDay
33%6%11%26%17%5%
2310
16th to endDay
30%310%29%20%6%
2310
July1st to 15thDay
15%37%24%31%16%
2161
16th to endDay
14%36%19%35%20%
2294
August1st to 15thDay
15%38%26%34%12%
2293
16th to endDay
17%39%27%31%10%
2148
September1st to 15thDay
17%39%26%33%10%
1980
16th to endDay
27%5%14%25%19%6%
1851
October1st to 15thDay
34%6%14%29%14%
1650
16th to endDay
39%8%18%22%9%
1631
November1st to 15thDay
50%7%15%16%6%2
1515
16th to endDay
58%8%13%14%6%
1440
December1st to 15thDay
58%9%14%12%5%
1440
16th to endDay
63%6%10%14%4
1536
January1st to 15thNight
60%8%13%12%31
2506
16th to endNight
60%8%16%11%1
2688
February1st to 15thNight
50%9%18%15%5%
2332
16th to endNight
44%10%15%20%8%
1943
March1st to 15thNight
46%6%15%23%7%
2154
16th to endNight
42%8%13%27%7%
2003
April1st to 15thNight
41%5%13%24%14%
1799
16th to endNight
30%7%16%29%15%1
1608
May1st to 15thNight
27%49%30%23%4
1320
16th to endNight
37%6%14%27%12%1
1368
June1st to 15thNight
29%5%10%28%20%5%
1320
16th to endNight
24%413%28%24%5%
1320
July1st to 15thNight
14%28%23%31%18%
1240
16th to endNight
9%26%19%34%26%
1304
August1st to 15thNight
10%28%23%39%15%
1312
16th to endNight
16%38%24%33%13%
1698
September1st to 15thNight
13%39%23%34%15%
1650
16th to endNight
24%411%29%20%9%
1776
October1st to 15thNight
34%411%27%19%1
1980
16th to endNight
41%8%13%26%10%
2241
November1st to 15thNight
45%8%17%16%8%3
2343
16th to endNight
55%8%11%16%7%
2520
December1st to 15thNight
55%8%16%15%3
2520
16th to endNight
59%8%12%11%7%
2688

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%318%25%26%5%
60
16th to endDay
29%115%23%15%14%
64
February1st to 15thDay
19%417%35%19%3
191
16th to endDay
18%7%20%31%18%3
230
March1st to 15thDay
17%13%27%31%10%1
270
16th to endDay
16%13%29%26%13%1
288
April1st to 15thDay
10%15%28%21%15%7%
269
16th to endDay
8%11%33%23%13%9%
243
May1st to 15thDay
10%15%29%21%18%3
228
16th to endDay
10%5%17%25%29%10%
266
June1st to 15thDay
9%10%19%31%19%9%
255
16th to endDay
8%7%26%26%21%9%
255
July1st to 15thDay
2321%33%27%11%
245
16th to endDay
1421%33%26%12%
271
August1st to 15thDay
5%313%32%28%16%
255
16th to endDay
25%22%28%29%11%
268
September1st to 15thDay
6%5%20%30%23%14%
255
16th to endDay
48%24%28%27%6%
255
October1st to 15thDay
13%9%25%27%19%3
255
16th to endDay
23%413%35%19%3
143
November1st to 15thDay
11%7%30%36%13%
79
16th to endDay
15%5%20%28%30%1
60
December1st to 15thDay
18%5%21%38%13%3
60
16th to endDay
17%310%45%18%4
64
January1st to 15thNight
21%420%32%18%2
720
16th to endNight
18%315%38%20%3
768
February1st to 15thNight
17%321%34%18%4
704
16th to endNight
11%5%25%34%18%4
632
March1st to 15thNight
13%5%23%38%16%1
720
16th to endNight
9%5%30%37%14%2
768
April1st to 15thNight
12%6%25%32%20%3
719
16th to endNight
7%6%29%32%18%5%
564
May1st to 15thNight
8%6%31%29%19%4
330
16th to endNight
8%321%38%26%2
343
June1st to 15thNight
7%430%32%22%2
330
16th to endNight
5%433%35%19%2
330
July1st to 15thNight
15%22%34%32%3
310
16th to endNight
2419%39%31%2
348
August1st to 15thNight
1115%33%42%5%
330
16th to endNight
2317%33%34%7%
648
September1st to 15thNight
3319%27%33%12%
660
16th to endNight
6%319%32%33%6%
656
October1st to 15thNight
11%320%33%25%4
660
16th to endNight
14%217%39%20%5%
704
November1st to 15thNight
18%322%41%12%1
700
16th to endNight
18%7%21%27%21%3
720
December1st to 15thNight
18%419%39%17%
720
16th to endNight
22%219%41%12%
768
Page generated at 2017-04-25 04:48:21. Version ac04

Copyright 2017 A. Danko


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