Oak Flat Picnic Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Oak Flat Picnic Area clear sky chart from 2005-11-05 to

2017-09-12
.

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%
15647
31%
46886
21%
15605
67%
15605
44%
24120

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
55%
718
33%
2327
25%
716
67%
716
49%
1064
January16th to endNight
50%
768
35%
2496
25%
768
65%
768
48%
1170
February1st to 15thNight
49%
702
31%
2217
21%
699
61%
699
45%
1081
February16th to endNight
40%
632
38%
1894
19%
632
61%
632
46%
931
March1st to 15thNight
51%
720
34%
2022
20%
720
61%
720
45%
1070
March16th to endNight
51%
729
35%
2073
18%
729
64%
729
51%
1020
April1st to 15thNight
41%
539
33%
1798
17%
539
61%
539
42%
842
April16th to endNight
40%
540
36%
1800
20%
540
64%
540
44%
831
May1st to 15thNight
50%
539
27%
1799
20%
539
63%
539
41%
881
May16th to endNight
55%
562
31%
1589
18%
561
67%
561
48%
816
June1st to 15thNight
62%
540
26%
1440
16%
540
69%
540
48%
779
June16th to endNight
72%
540
25%
1440
20%
540
74%
540
50%
785
July1st to 15thNight
71%
510
17%
1476
15%
510
72%
510
31%
928
July16th to endNight
75%
564
18%
1593
17%
531
76%
531
30%
986
August1st to 15thNight
76%
539
17%
1712
19%
536
76%
536
30%
1027
August16th to endNight
76%
573
24%
1910
27%
573
78%
573
32%
1104
September1st to 15thNight
72%
530
23%
1766
24%
530
75%
530
29%
1054
September16th to endNight
67%
528
34%
1777
28%
528
75%
528
46%
841
October1st to 15thNight
62%
660
36%
1980
24%
660
71%
660
49%
980
October16th to endNight
66%
704
38%
2112
24%
704
75%
704
55%
972
November1st to 15thNight
64%
754
40%
2154
25%
754
73%
754
62%
974
November16th to endNight
60%
900
38%
2340
23%
900
67%
900
53%
1226
December1st to 15thNight
51%
900
33%
2487
18%
900
61%
900
49%
1281
December16th to endNight
46%
956
31%
2684
18%
956
57%
956
42%
1477

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
331342445%7%58%
47761
Night
331342445%7%59%
47083
TransparencyDay
22%49%20%26%15%
47457
Night
22%410%20%27%15%
46888
SeeingDay
6%9%23%30%24%7%
5473
Night
46%25%37%23%2
15653

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
1212433446%64%
1611
16th to endDay
341332335%5%63%
1728
February1st to 15thDay
2315%323445%63%
1645
16th to endDay
131332445%7%61%
1580
March1st to 15thDay
2314424446%59%
1935
16th to endDay
121432345%7%63%
2151
April1st to 15thDay
321332445%7%61%
2150
16th to endDay
2312313345%67%
2160
May1st to 15thDay
231342445%8%59%
2151
16th to endDay
221331345%6%65%
2519
June1st to 15thDay
121331345%8%63%
2520
16th to endDay
12132245%6%7%62%
2520
July1st to 15thDay
5%226%5%36%6%8%11%41%
2389
16th to endDay
5%3347%47%6%8%11%37%
2467
August1st to 15thDay
4325%5%36%7%8%10%42%
2238
16th to endDay
5%4135%45%6%7%9%45%
2292
September1st to 15thDay
6%4246%35%5%8%8%43%
2113
16th to endDay
321232345%5%63%
1851
October1st to 15thDay
6%213213345%65%
1650
16th to endDay
212212335%73%
1760
November1st to 15thDay
112212447%69%
1691
16th to endDay
2312213246%68%
1620
December1st to 15thDay
241222335%7%64%
1470
16th to endDay
35%24423448%57%
1550
January1st to 15thNight
331233346%67%
2327
16th to endNight
3312213447%63%
2496
February1st to 15thNight
1413423446%63%
2207
16th to endNight
1413423446%62%
1894
March1st to 15thNight
2323424436%60%
2022
16th to endNight
3212314346%66%
2073
April1st to 15thNight
2323324347%62%
1798
16th to endNight
2314323345%66%
1800
May1st to 15thNight
2313425%45%8%58%
1799
16th to endNight
322232345%5%63%
1589
June1st to 15thNight
21234345%7%8%56%
1440
16th to endNight
2214415%6%6%9%55%
1440
July1st to 15thNight
5%325%5%46%6%9%9%40%
1566
16th to endNight
4335%6%47%7%9%12%35%
1701
August1st to 15thNight
4424437%6%9%10%40%
1721
16th to endNight
33146%36%6%8%11%42%
1910
September1st to 15thNight
7%5%145%35%6%8%9%40%
1766
16th to endNight
4214323335%64%
1777
October1st to 15thNight
4213313345%65%
1980
16th to endNight
22222334470%
2112
November1st to 15thNight
12213335%73%
2154
16th to endNight
321242233468%
2340
December1st to 15thNight
3313323347%62%
2487
16th to endNight
241442346%8%55%
2684

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
19%39%28%32%6%
1612
16th to endDay
21%37%23%32%11%
1728
February1st to 15thDay
21%38%27%24%14%
1646
16th to endDay
20%27%22%32%14%
1580
March1st to 15thDay
22%45%20%32%14%
1935
16th to endDay
19%27%17%37%15%
2151
April1st to 15thDay
21%35%20%33%16%
2150
16th to endDay
18%3417%35%21%
2160
May1st to 15thDay
21%47%16%28%20%
2151
16th to endDay
19%46%17%27%25%
2522
June1st to 15thDay
17%48%15%22%32%
2520
16th to endDay
17%48%16%21%30%
2520
July1st to 15thDay
31%8%14%16%15%14%
2250
16th to endDay
34%9%16%25%11%1
2312
August1st to 15thDay
31%9%16%20%15%5%
2223
16th to endDay
30%8%13%22%19%6%
2292
September1st to 15thDay
32%8%12%18%17%9%
2113
16th to endDay
19%47%20%28%19%
1851
October1st to 15thDay
20%36%17%30%20%
1650
16th to endDay
15%26%19%36%19%
1760
November1st to 15thDay
13%37%23%38%14%
1691
16th to endDay
17%2423%37%15%
1620
December1st to 15thDay
19%212%33%24%7%
1470
16th to endDay
25%314%26%25%4
1550
January1st to 15thNight
17%310%25%33%8%
2327
16th to endNight
19%39%23%33%10%
2496
February1st to 15thNight
21%310%23%25%15%
2217
16th to endNight
20%27%20%34%14%
1894
March1st to 15thNight
22%47%20%31%14%
2022
16th to endNight
18%27%16%38%15%
2073
April1st to 15thNight
20%26%20%31%17%
1798
16th to endNight
20%26%14%34%22%
1800
May1st to 15thNight
22%410%15%27%20%
1800
16th to endNight
21%49%15%26%23%
1590
June1st to 15thNight
22%410%13%16%31%
1440
16th to endNight
21%5%11%13%17%30%
1440
July1st to 15thNight
34%8%13%17%13%12%
1476
16th to endNight
33%9%21%23%10%1
1593
August1st to 15thNight
32%9%18%20%12%7%
1712
16th to endNight
29%9%14%26%13%6%
1910
September1st to 15thNight
33%8%16%16%15%9%
1766
16th to endNight
20%48%17%26%22%
1777
October1st to 15thNight
20%37%16%28%23%
1980
16th to endNight
16%26%16%35%22%
2112
November1st to 15thNight
12%25%21%40%16%
2154
16th to endNight
19%3418%34%19%
2340
December1st to 15thNight
20%310%27%29%8%
2487
16th to endNight
24%411%29%24%4
2684

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
6%5%42%28%15%1
90
16th to endDay
212%41%23%15%4
96
February1st to 15thDay
311%36%30%15%3
90
16th to endDay
7%8%39%24%18%1
81
March1st to 15thDay
9%18%28%26%17%
225
16th to endDay
9%21%34%22%10%1
288
April1st to 15thDay
10%20%33%24%8%2
269
16th to endDay
11%23%35%20%7%1
270
May1st to 15thDay
5%18%39%27%7%1
288
16th to endDay
49%30%35%17%1
442
June1st to 15thDay
45%20%31%34%4
495
16th to endDay
3213%31%40%9%
495
July1st to 15thDay
3115%33%36%10%
354
16th to endDay
6%15%24%34%26%
327
August1st to 15thDay
327%35%35%15%
315
16th to endDay
7%113%34%29%13%
332
September1st to 15thDay
7%118%36%27%9%
300
16th to endDay
6%6%15%41%27%3
164
October1st to 15thDay
13%320%30%23%10%
90
16th to endDay
10%5%19%26%27%11%
96
November1st to 15thDay
414%18%27%30%4
90
16th to endDay
8%18%32%27%12%
90
December1st to 15thDay
118%28%35%13%2
90
16th to endDay
12%17%32%29%7%1
96
January1st to 15thNight
47%27%38%18%3
720
16th to endNight
5%6%33%34%17%1
768
February1st to 15thNight
49%33%37%13%1
704
16th to endNight
313%39%35%7%
632
March1st to 15thNight
410%29%38%15%
720
16th to endNight
310%32%39%13%
729
April1st to 15thNight
5%15%35%35%7%
539
16th to endNight
5%11%39%35%7%
540
May1st to 15thNight
46%33%42%12%
540
16th to endNight
45%28%40%20%
563
June1st to 15thNight
2325%48%20%
540
16th to endNight
2115%47%29%2
540
July1st to 15thNight
5%18%37%41%4
510
16th to endNight
6%425%54%8%
564
August1st to 15thNight
6%5%28%48%10%
539
16th to endNight
318%32%48%6%
573
September1st to 15thNight
8%110%34%41%3
530
16th to endNight
5%117%35%34%4
528
October1st to 15thNight
5%422%40%23%3
660
16th to endNight
4421%37%26%4
704
November1st to 15thNight
16%25%37%26%2
754
16th to endNight
48%24%33%24%4
900
December1st to 15thNight
7%7%30%37%15%1
900
16th to endNight
5%10%32%38%10%1
956
Page generated at 2017-09-13 05:39:09. Version ac04

Copyright 2017 A. Danko


Oak Flat Picnic Area Clear Sky Chart | Charts Home