Whiskeytown National Recreation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Whiskeytown National Recreation Area clear sky chart from 2005-11-06 to 2024-01-14.

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
54%
23220
28%
74750
21%
23164
64%
23164
39%
39632

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 10thNight
43%
760
17%
2646
13%
756
51%
756
23%
1649
January11th to 20thNight
40%
734
21%
2413
14%
734
51%
734
25%
1483
January21st to endNight
42%
792
26%
2574
18%
792
54%
792
26%
1570
February1st to 10thNight
46%
720
26%
2340
20%
720
57%
720
30%
1360
February11th to 20thNight
40%
701
25%
2269
16%
700
55%
700
29%
1313
February21st to endNight
38%
592
25%
1776
15%
592
51%
592
30%
1043
March1st to 10thNight
36%
720
16%
2028
8%
720
44%
720
22%
1405
March11th to 20thNight
44%
720
22%
1980
13%
720
52%
720
30%
1260
March21st to endNight
38%
792
21%
2149
10%
792
47%
792
29%
1360
April1st to 10thNight
38%
720
22%
1800
8%
720
47%
720
32%
1169
April11th to 20thNight
43%
711
27%
1779
8%
711
52%
711
40%
1052
April21st to endNight
49%
694
27%
1774
11%
694
57%
694
51%
949
May1st to 10thNight
47%
540
30%
1620
14%
540
59%
540
46%
790
May11th to 20thNight
53%
372
28%
1434
23%
372
63%
372
39%
656
May21st to endNight
50%
388
26%
1552
20%
388
64%
388
36%
705
June1st to 10thNight
54%
360
23%
1440
21%
360
66%
360
36%
668
June11th to 20thNight
53%
360
33%
1440
29%
360
74%
360
58%
498
June21st to endNight
69%
360
34%
1440
39%
360
81%
360
63%
488
July1st to 10thNight
80%
350
35%
1400
44%
350
87%
350
73%
439
July11th to 20thNight
81%
352
38%
1396
46%
352
86%
352
69%
454
July21st to endNight
89%
591
40%
1674
35%
558
92%
558
83%
627
August1st to 10thNight
85%
537
39%
1602
32%
534
88%
534
75%
636
August11th to 20thNight
83%
559
42%
1627
29%
559
87%
559
78%
641
August21st to endNight
85%
792
45%
1980
28%
792
88%
792
86%
853
September1st to 10thNight
79%
720
46%
1800
26%
720
85%
720
84%
785
September11th to 20thNight
78%
720
44%
1800
30%
720
83%
720
72%
860
September21st to endNight
69%
720
39%
2060
32%
720
78%
720
65%
920
October1st to 10thNight
62%
720
32%
2160
26%
720
74%
720
54%
988
October11th to 20thNight
62%
720
39%
2160
30%
720
78%
720
54%
1012
October21st to endNight
57%
792
37%
2376
28%
792
71%
792
48%
1172
November1st to 10thNight
57%
740
28%
2328
24%
740
65%
740
36%
1285
November11th to 20thNight
51%
760
22%
2577
16%
760
61%
760
32%
1431
November21st to endNight
48%
760
25%
2660
19%
760
60%
760
33%
1394
December1st to 10thNight
47%
760
24%
2660
18%
760
57%
760
28%
1531
December11th to 20thNight
39%
760
19%
3224
15%
759
50%
759
17%
2197
December21st to endNight
36%
831
15%
4812
15%
817
48%
817
13%
2989

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
11%313323346%62%
74724
Night
13%413323346%58%
75046
TransparencyDay
24%38%20%25%21%
74439
Night
28%39%20%23%17%
74852
SeeingDay
13%10%25%31%18%5%
13955
Night
14%6%21%34%22%2
23229

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 10thDay
25%6%24325%45%8%36%
1519
11th to 20thDay
21%6%23323336%48%
1614
21st to endDay
17%7%25%433436%46%
1782
February1st to 10thDay
18%5%135%3445%6%45%
1620
11th to 20thDay
16%5%13423347%52%
1579
21st to endDay
18%5%2442446%7%45%
1480
March1st to 10thDay
22%8%35%5%35%447%35%
1930
11th to 20thDay
20%6%1442335%9%43%
1980
21st to endDay
21%5%2442435%8%42%
2205
April1st to 10thDay
18%6%2442446%7%44%
2160
11th to 20thDay
13%4245%23446%54%
2129
21st to endDay
5%324423447%61%
2182
May1st to 10thDay
7%5%13323347%63%
2340
11th to 20thDay
7%41332335%7%61%
2459
21st to endDay
8%31332336%8%59%
2723
June1st to 10thDay
7%31332445%7%61%
2520
11th to 20thDay
3211222246%76%
2520
21st to endDay
421121223480%
2520
July1st to 10thDay
1111223484%
2520
11th to 20thDay
111111222485%
2513
21st to endDay
111111123485%
2546
August1st to 10thDay
211121123482%
2328
11th to 20thDay
11111112388%
2272
21st to endDay
11111111388%
2376
September1st to 10thDay
1111112488%
2160
11th to 20thDay
422222346%74%
2160
21st to endDay
3212212235%77%
1896
October1st to 10thDay
5%21322223474%
1800
11th to 20thDay
8%312122447%67%
1800
21st to endDay
13%224212346%61%
1980
November1st to 10thDay
14%424434446%51%
1748
11th to 20thDay
14%5%1432446%9%49%
1601
21st to endDay
12%42333435%7%55%
1520
December1st to 10thDay
22%5%23323337%49%
1520
11th to 20thDay
34%5%24333446%31%
1928
21st to endDay
29%5%2442445%6%37%
2794
January1st to 10thNight
23%6%2333446%7%40%
2646
11th to 20thNight
22%5%14423446%46%
2413
21st to endNight
19%6%24324446%46%
2574
February1st to 10thNight
20%413323446%49%
2340
11th to 20thNight
18%5%133235%46%49%
2267
21st to endNight
15%4245%2445%6%49%
1776
March1st to 10thNight
23%8%34424346%38%
2028
11th to 20thNight
19%6%2442445%9%40%
1980
21st to endNight
19%5%144235%46%46%
2149
April1st to 10thNight
16%5%3443435%7%46%
1800
11th to 20thNight
9%42442445%6%56%
1779
21st to endNight
8%32332335%7%62%
1774
May1st to 10thNight
7%312223347%65%
1620
11th to 20thNight
7%32332445%8%60%
1434
21st to endNight
8%32342336%6%61%
1552
June1st to 10thNight
6%41332446%7%59%
1440
11th to 20thNight
4212112245%77%
1440
21st to endNight
32221223381%
1440
July1st to 10thNight
111111122485%
1440
11th to 20thNight
111121232482%
1444
21st to endNight
11111112388%
1773
August1st to 10thNight
211111123384%
1611
11th to 20thNight
11121232385%
1627
21st to endNight
11111112389%
1980
September1st to 10thNight
11111112389%
1800
11th to 20thNight
311212236%77%
1800
21st to endNight
3212212335%76%
2060
October1st to 10thNight
5%31232234473%
2160
11th to 20thNight
7%212222335%72%
2160
21st to endNight
11%212212346%65%
2376
November1st to 10thNight
13%41442446%7%52%
2328
11th to 20thNight
14%3233245%6%9%49%
2577
21st to endNight
13%41442345%6%55%
2660
December1st to 10thNight
23%5%22313347%48%
2660
11th to 20thNight
33%5%1332335%7%34%
3276
21st to endNight
27%7%24423346%37%
4862

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 10thDay
46%5%13%23%9%4
1519
11th to 20thDay
40%29%19%17%12%
1614
21st to endDay
41%38%17%23%9%
1782
February1st to 10thDay
39%410%20%18%9%
1620
11th to 20thDay
34%310%22%26%6%
1588
21st to endDay
37%49%23%21%7%
1480
March1st to 10thDay
48%6%9%16%16%5%
1930
11th to 20thDay
39%49%24%19%6%
1980
21st to endDay
40%413%21%17%5%
2205
April1st to 10thDay
38%414%20%19%6%
2160
11th to 20thDay
30%312%24%20%11%
2132
21st to endDay
22%411%27%27%9%
2182
May1st to 10thDay
22%29%23%28%15%
2340
11th to 20thDay
22%39%26%27%14%
2462
21st to endDay
22%311%28%26%9%
2724
June1st to 10thDay
22%49%23%27%15%
2520
11th to 20thDay
10%28%20%33%26%
2520
21st to endDay
11%2314%31%39%
2520
July1st to 10thDay
6%2314%28%47%
2451
11th to 20thDay
7%15%12%28%48%
2438
21st to endDay
6%2111%27%52%
2405
August1st to 10thDay
8%2317%33%38%
2312
11th to 20thDay
6%1211%33%47%
2272
21st to endDay
5%2115%35%42%
2376
September1st to 10thDay
5%1211%24%57%
2160
11th to 20thDay
12%25%21%36%24%
2160
21st to endDay
12%25%19%32%30%
1896
October1st to 10thDay
15%35%20%29%28%
1800
11th to 20thDay
18%38%20%26%25%
1800
21st to endDay
25%28%20%23%21%
1980
November1st to 10thDay
32%49%24%18%12%
1748
11th to 20thDay
32%5%14%23%17%8%
1601
21st to endDay
30%310%22%24%11%
1520
December1st to 10thDay
38%28%20%22%10%
1520
11th to 20thDay
56%37%16%14%4
1928
21st to endDay
49%411%21%13%3
2794
January1st to 10thNight
42%5%15%22%11%5%
2646
11th to 20thNight
41%410%17%16%12%
2413
21st to endNight
41%38%17%23%8%
2574
February1st to 10thNight
37%29%23%21%9%
2340
11th to 20thNight
36%39%21%24%7%
2269
21st to endNight
35%311%21%23%7%
1776
March1st to 10thNight
47%6%10%16%17%5%
2028
11th to 20thNight
39%411%22%17%7%
1980
21st to endNight
37%5%12%25%16%4
2149
April1st to 10thNight
38%415%20%17%8%
1800
11th to 20thNight
28%413%26%19%10%
1779
21st to endNight
20%413%32%25%7%
1774
May1st to 10thNight
20%310%23%33%10%
1620
11th to 20thNight
22%5%12%26%25%10%
1434
21st to endNight
23%412%33%21%7%
1552
June1st to 10thNight
23%5%10%24%27%10%
1440
11th to 20thNight
10%28%22%34%23%
1440
21st to endNight
11%1416%36%32%
1440
July1st to 10thNight
7%1315%33%41%
1400
11th to 20thNight
8%2410%29%48%
1396
21st to endNight
5%1212%28%52%
1674
August1st to 10thNight
8%2219%37%32%
1602
11th to 20thNight
7%2315%33%41%
1627
21st to endNight
5%1217%35%41%
1980
September1st to 10thNight
42211%26%55%
1800
11th to 20thNight
10%35%22%38%23%
1800
21st to endNight
11%36%20%26%34%
2060
October1st to 10thNight
16%26%17%29%29%
2160
11th to 20thNight
18%35%22%26%26%
2160
21st to endNight
22%28%21%24%22%
2376
November1st to 10thNight
30%413%23%18%12%
2328
11th to 20thNight
31%5%14%23%18%9%
2577
21st to endNight
30%310%22%22%12%
2660
December1st to 10thNight
38%29%18%22%10%
2660
11th to 20thNight
52%37%16%19%3
3276
21st to endNight
49%311%19%13%3
4862

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 10thDay
41%8%22%20%8%2
180
11th to 20thDay
30%7%24%24%11%4
316
21st to endDay
22%10%21%28%14%4
374
February1st to 10thDay
21%12%22%25%18%2
340
11th to 20thDay
23%13%32%23%9%1
337
21st to endDay
21%11%30%27%9%1
346
March1st to 10thDay
30%16%27%19%6%1
420
11th to 20thDay
28%11%25%23%12%2
420
21st to endDay
25%15%25%24%10%1
462
April1st to 10thDay
25%16%23%26%10%1
420
11th to 20thDay
20%17%28%22%10%3
412
21st to endDay
9%19%30%25%13%5%
420
May1st to 10thDay
11%18%32%24%13%3
423
11th to 20thDay
12%13%27%28%14%5%
448
21st to endDay
9%14%24%33%16%4
485
June1st to 10thDay
8%13%23%31%21%4
450
11th to 20thDay
7%17%29%31%14%2
450
21st to endDay
47%26%34%24%5%
450
July1st to 10thDay
15%27%42%20%5%
446
11th to 20thDay
320%44%25%8%
444
21st to endDay
216%46%27%8%
487
August1st to 10thDay
2222%38%26%10%
447
11th to 20thDay
25%18%37%28%11%
437
21st to endDay
2420%39%27%7%
495
September1st to 10thDay
2322%39%28%6%
450
11th to 20thDay
46%21%40%21%7%
450
21st to endDay
48%28%35%21%4
450
October1st to 10thDay
6%12%25%29%22%6%
450
11th to 20thDay
8%6%26%32%22%6%
450
21st to endDay
16%8%24%27%20%5%
495
November1st to 10thDay
18%7%23%27%21%4
344
11th to 20thDay
16%427%27%19%6%
219
21st to endDay
14%9%28%31%16%3
180
December1st to 10thDay
26%10%24%18%16%5%
180
11th to 20thDay
28%5%25%25%12%6%
180
21st to endDay
21%10%27%26%14%3
198
January1st to 10thNight
26%5%22%28%16%3
760
11th to 20thNight
24%7%23%31%12%3
734
21st to endNight
22%5%23%30%17%3
792
February1st to 10thNight
21%6%22%34%16%2
720
11th to 20thNight
21%8%24%30%13%3
704
21st to endNight
19%8%27%34%10%1
592
March1st to 10thNight
28%8%22%27%13%2
720
11th to 20thNight
23%5%22%31%17%1
720
21st to endNight
21%11%24%31%12%1
792
April1st to 10thNight
18%11%28%28%14%2
720
11th to 20thNight
14%10%29%32%14%2
711
21st to endNight
9%9%30%33%18%1
694
May1st to 10thNight
10%10%29%33%17%1
540
11th to 20thNight
9%7%25%35%23%1
372
21st to endNight
9%8%26%35%21%1
389
June1st to 10thNight
8%8%27%38%20%1
360
11th to 20thNight
6%9%31%38%17%1
360
21st to endNight
4222%48%24%1
360
July1st to 10thNight
1116%46%35%2
350
11th to 20thNight
1114%41%39%3
352
21st to endNight
18%41%46%5%
591
August1st to 10thNight
229%36%45%5%
537
11th to 20thNight
2113%39%41%4
559
21st to endNight
2110%40%44%3
792
September1st to 10thNight
1216%41%37%3
720
11th to 20thNight
4313%38%39%4
720
21st to endNight
46%19%36%32%4
720
October1st to 10thNight
6%8%20%36%27%3
720
11th to 20thNight
8%422%35%27%4
720
21st to endNight
13%5%22%33%22%4
792
November1st to 10thNight
13%6%18%36%24%3
740
11th to 20thNight
16%423%38%18%1
760
21st to endNight
15%6%24%35%18%2
760
December1st to 10thNight
26%421%33%13%3
760
11th to 20thNight
28%5%22%30%14%2
760
21st to endNight
25%6%26%31%12%1
836
Page generated at 2024-01-11 01:22:40. Version ac07

Copyright 2024 Attilla Danko


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