Theodore Roosevelt National Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Theodore Roosevelt National Park clear sky chart from 2005-11-05 to 2017-09-23.

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%
16230
17%
46901
10%
16190
46%
16190
28%
30121

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
27%
897
14%
2506
8%
895
32%
895
21%
1758
January16th to endNight
26%
960
13%
2688
5%
960
33%
960
18%
1945
February1st to 15thNight
31%
773
9%
2361
5%
773
35%
773
18%
1702
February16th to endNight
37%
632
13%
1902
7%
632
43%
632
22%
1287
March1st to 15thNight
36%
720
15%
2160
9%
720
42%
720
25%
1434
March16th to endNight
36%
630
13%
2010
8%
630
42%
630
20%
1386
April1st to 15thNight
37%
539
18%
1798
12%
539
47%
539
26%
1113
April16th to endNight
40%
540
17%
1674
14%
540
45%
540
24%
1115
May1st to 15thNight
47%
540
16%
1449
8%
540
50%
540
32%
933
May16th to endNight
47%
563
13%
1498
7%
561
49%
561
27%
1020
June1st to 15thNight
43%
540
9%
1440
5%
540
46%
540
31%
941
June16th to endNight
53%
540
11%
1440
6%
540
56%
540
42%
839
July1st to 15thNight
62%
510
14%
1360
8%
510
65%
510
52%
724
July16th to endNight
63%
564
21%
1416
13%
531
65%
531
55%
724
August1st to 15thNight
62%
539
24%
1432
16%
536
67%
536
50%
767
August16th to endNight
62%
573
28%
1857
25%
573
70%
573
48%
900
September1st to 15thNight
62%
540
25%
1800
23%
540
70%
540
41%
912
September16th to endNight
51%
516
25%
1885
22%
516
59%
516
33%
991
October1st to 15thNight
38%
621
23%
1941
17%
621
44%
621
26%
1210
October16th to endNight
41%
858
22%
2266
11%
858
47%
858
30%
1500
November1st to 15thNight
39%
875
24%
2290
11%
875
46%
875
33%
1470
November16th to endNight
32%
900
18%
2520
8%
900
40%
900
26%
1683
December1st to 15thNight
29%
900
13%
2520
6%
900
36%
900
18%
1856
December16th to endNight
26%
960
15%
2688
6%
960
34%
960
19%
1911

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
9%7%35%5%3445%7%43%
48015
Night
8%7%35%5%3445%7%44%
47067
Cloud CoverDay
9%6%35%5%2445%7%44%
48025
Night
8%6%35%5%3445%7%44%
47070
Cloud CoverDay
9%6%35%5%3445%7%43%
48025
Night
8%7%35%5%3445%7%44%
47072
Cloud CoverDay
9%7%35%5%3445%7%43%
48023
Night
8%7%36%5%35%45%7%43%
47072
TransparencyDay
38%6%15%24%12%1
47698
Night
38%6%15%24%12%2
46901
SeeingDay
12%7%28%31%16%3
6186
Night
11%7%33%34%11%
16237

By Month

Percentage Cloud Cover NE (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
5%9%5%7%7%36%5%7%7%35%
1432
16th to endDay
38%49%6%5%6%5%5%9%34%
1536
February1st to 15thDay
7%11%6%8%7%3445%8%32%
1512
16th to endDay
5%12%5%11%8%35%5%6%7%28%
1572
March1st to 15thDay
6%8%37%6%35%45%9%40%
1790
16th to endDay
13%11%46%5%3445%6%34%
2211
April1st to 15thDay
10%8%46%6%35%45%7%37%
2150
16th to endDay
16%7%35%5%345%5%6%35%
2284
May1st to 15thDay
13%9%245%34446%41%
2499
16th to endDay
19%5%245%3346%8%36%
2616
June1st to 15thDay
15%5%25%4345%6%7%38%
2520
16th to endDay
7%3123245%6%8%54%
2520
July1st to 15thDay
421333445%8%57%
2520
16th to endDay
5%21332445%7%59%
2656
August1st to 15thDay
7%31342445%8%55%
2520
16th to endDay
7%31322335%7%59%
2343
September1st to 15thDay
8%5%2331235%6%55%
2160
16th to endDay
12%413323236%56%
1911
October1st to 15thDay
14%6%2432345%6%45%
1686
16th to endDay
11%9%2442445%8%43%
1595
November1st to 15thDay
7%7%35%4245%5%7%46%
1566
16th to endDay
8%9%48%5%36%46%8%35%
1440
December1st to 15thDay
6%11%5%9%6%36%6%6%7%29%
1440
16th to endDay
7%12%6%8%6%45%5%47%30%
1536
January1st to 15thNight
5%9%5%7%7%35%5%6%6%35%
2506
16th to endNight
5%10%5%8%8%35%5%5%7%33%
2688
February1st to 15thNight
7%10%47%7%47%5%5%7%31%
2357
16th to endNight
5%9%5%8%6%345%6%9%35%
1902
March1st to 15thNight
6%7%45%5%445%6%8%39%
2147
16th to endNight
12%8%36%5%35%5%6%7%34%
2010
April1st to 15thNight
9%7%345%25%46%7%43%
1798
16th to endNight
15%7%25%43445%6%40%
1674
May1st to 15thNight
12%6%1433445%7%46%
1449
16th to endNight
15%424425%5%6%7%41%
1497
June1st to 15thNight
12%5%23425%45%8%45%
1440
16th to endNight
5%214424446%58%
1440
July1st to 15thNight
321331345%9%62%
1440
16th to endNight
311231335%6%67%
1512
August1st to 15thNight
5%32423348%61%
1440
16th to endNight
431321235%7%63%
1857
September1st to 15thNight
6%21331345%7%60%
1800
16th to endNight
11%41321335%6%54%
1885
October1st to 15thNight
13%8%23423446%45%
1941
16th to endNight
9%8%35%5%34348%43%
2266
November1st to 15thNight
7%7%2442445%7%47%
2290
16th to endNight
7%7%37%6%35%5%6%8%40%
2520
December1st to 15thNight
7%9%5%10%8%46%5%5%6%31%
2520
16th to endNight
8%10%5%10%7%34445%35%
2688

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
5%10%47%7%36%5%5%9%34%
1433
16th to endDay
37%48%7%5%6%6%6%9%34%
1536
February1st to 15thDay
6%11%6%8%6%35%35%9%32%
1512
16th to endDay
411%6%11%9%35%5%6%6%29%
1572
March1st to 15thDay
6%7%46%7%35%45%9%40%
1800
16th to endDay
12%11%47%5%3445%6%33%
2210
April1st to 15thDay
9%9%36%6%25%45%8%37%
2150
16th to endDay
16%8%35%5%3445%7%35%
2284
May1st to 15thDay
13%8%25%5%3335%6%41%
2499
16th to endDay
18%6%25%42445%7%37%
2616
June1st to 15thDay
14%5%25%5%35%5%6%7%39%
2520
16th to endDay
6%3134236%6%8%54%
2520
July1st to 15thDay
421342445%8%57%
2520
16th to endDay
421333346%7%59%
2656
August1st to 15thDay
6%31332445%8%55%
2520
16th to endDay
7%31331435%7%59%
2343
September1st to 15thDay
7%5%24313347%56%
2160
16th to endDay
12%413313236%57%
1911
October1st to 15thDay
13%5%2432445%6%46%
1686
16th to endDay
10%9%24325%35%8%43%
1595
November1st to 15thDay
7%6%345%25%5%5%7%46%
1566
16th to endDay
8%8%48%6%35%47%8%34%
1440
December1st to 15thDay
7%11%5%8%7%36%5%6%7%30%
1440
16th to endDay
7%13%6%7%7%45%45%7%31%
1536
January1st to 15thNight
5%9%5%8%7%35%5%6%7%35%
2506
16th to endNight
49%5%8%7%45%5%5%7%34%
2688
February1st to 15thNight
6%10%47%7%47%6%5%7%32%
2350
16th to endNight
48%5%8%6%35%5%7%9%34%
1902
March1st to 15thNight
6%7%45%5%35%6%5%8%39%
2160
16th to endNight
11%8%36%6%35%5%6%7%34%
2007
April1st to 15thNight
8%8%3443446%7%43%
1798
16th to endNight
16%6%245%2445%6%40%
1674
May1st to 15thNight
12%6%1442445%7%46%
1448
16th to endNight
15%4244245%6%8%40%
1498
June1st to 15thNight
11%5%2442445%9%44%
1440
16th to endNight
5%213424446%58%
1440
July1st to 15thNight
221232346%7%63%
1440
16th to endNight
312213447%67%
1512
August1st to 15thNight
5%21222335%8%61%
1440
16th to endNight
431321335%7%63%
1857
September1st to 15thNight
7%21332345%6%60%
1800
16th to endNight
11%41331335%7%54%
1885
October1st to 15thNight
12%8%2432335%7%45%
1941
16th to endNight
9%8%25%5%33448%43%
2266
November1st to 15thNight
7%6%345%2446%7%48%
2290
16th to endNight
7%7%36%6%35%5%5%8%40%
2520
December1st to 15thNight
6%8%410%8%46%5%5%6%32%
2520
16th to endNight
8%11%5%9%6%33446%36%
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
5%9%5%7%7%36%5%6%7%35%
1432
16th to endDay
38%5%8%7%46%5%5%9%34%
1536
February1st to 15thDay
7%11%6%8%7%35%45%7%32%
1512
16th to endDay
5%12%5%11%8%45%5%6%7%28%
1572
March1st to 15thDay
6%8%37%6%3445%9%40%
1800
16th to endDay
13%11%47%6%2445%6%34%
2211
April1st to 15thDay
10%8%46%6%35%46%7%37%
2150
16th to endDay
16%7%35%5%245%5%6%35%
2284
May1st to 15thDay
13%9%245%34446%41%
2499
16th to endDay
18%5%2443446%8%36%
2616
June1st to 15thDay
15%5%245%345%6%7%38%
2520
16th to endDay
7%2123245%5%8%54%
2520
July1st to 15thDay
42134345%5%8%57%
2520
16th to endDay
5%21332435%7%59%
2656
August1st to 15thDay
7%31342345%8%55%
2520
16th to endDay
7%31332335%7%59%
2343
September1st to 15thDay
8%5%2332235%7%55%
2160
16th to endDay
12%413322236%56%
1911
October1st to 15thDay
14%6%3442345%6%46%
1686
16th to endDay
11%9%3442445%7%43%
1595
November1st to 15thDay
8%7%35%4245%5%7%46%
1566
16th to endDay
8%9%48%5%36%46%8%35%
1440
December1st to 15thDay
7%11%5%9%6%36%6%6%7%28%
1440
16th to endDay
7%12%6%8%6%45%5%47%30%
1536
January1st to 15thNight
5%9%5%7%8%45%46%6%35%
2506
16th to endNight
5%10%5%9%8%35%5%5%7%32%
2688
February1st to 15thNight
7%9%48%7%47%5%5%8%31%
2350
16th to endNight
5%9%5%8%6%345%6%9%35%
1902
March1st to 15thNight
6%7%46%5%45%5%6%8%39%
2160
16th to endNight
12%8%37%5%35%5%6%8%34%
2010
April1st to 15thNight
9%7%345%25%5%6%7%43%
1798
16th to endNight
15%6%25%424446%40%
1674
May1st to 15thNight
12%6%1433445%7%46%
1448
16th to endNight
15%424425%5%5%8%40%
1497
June1st to 15thNight
12%423325%45%8%45%
1440
16th to endNight
5%2143245%46%58%
1440
July1st to 15thNight
221331345%9%62%
1440
16th to endNight
3112313446%67%
1512
August1st to 15thNight
5%32323348%61%
1440
16th to endNight
431321235%7%63%
1857
September1st to 15thNight
7%22331345%7%60%
1800
16th to endNight
11%41322335%6%54%
1885
October1st to 15thNight
13%8%24324446%45%
1941
16th to endNight
9%7%35%5%3435%8%43%
2266
November1st to 15thNight
7%7%2443445%7%47%
2290
16th to endNight
7%6%36%6%35%5%6%8%39%
2520
December1st to 15thNight
7%9%5%10%7%46%5%5%6%31%
2520
16th to endNight
8%11%5%10%6%33446%35%
2688

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
5%10%5%6%6%37%5%6%7%34%
1432
16th to endDay
38%49%8%46%6%5%9%33%
1536
February1st to 15thDay
7%10%7%9%7%345%5%7%31%
1512
16th to endDay
412%6%11%8%46%45%7%27%
1572
March1st to 15thDay
6%8%36%7%3446%8%39%
1800
16th to endDay
12%10%37%6%3445%7%32%
2209
April1st to 15thDay
9%9%47%6%3445%7%37%
2150
16th to endDay
15%8%45%5%3445%7%34%
2284
May1st to 15thDay
12%9%25%5%34446%40%
2499
16th to endDay
18%6%25%5%2446%7%36%
2616
June1st to 15thDay
15%5%25%5%345%5%7%38%
2520
16th to endDay
7%3133345%6%8%52%
2520
July1st to 15thDay
421343446%8%56%
2520
16th to endDay
431342445%8%57%
2656
August1st to 15thDay
6%3133245%5%8%54%
2520
16th to endDay
7%31232435%7%58%
2343
September1st to 15thDay
8%5%2432235%6%55%
2160
16th to endDay
12%5%13312236%56%
1911
October1st to 15thDay
14%6%2433345%6%45%
1686
16th to endDay
11%8%35%42435%7%43%
1595
November1st to 15thDay
7%8%35%43445%7%46%
1566
16th to endDay
8%9%49%5%35%5%6%7%34%
1440
December1st to 15thDay
6%12%5%9%6%46%5%7%7%27%
1440
16th to endDay
7%12%6%7%7%446%47%30%
1536
January1st to 15thNight
5%9%5%7%7%36%5%6%7%34%
2506
16th to endNight
410%5%10%7%36%5%6%7%31%
2688
February1st to 15thNight
7%10%48%7%47%5%6%8%30%
2350
16th to endNight
5%9%5%9%6%335%6%9%34%
1902
March1st to 15thNight
6%7%46%6%35%5%5%9%38%
2160
16th to endNight
12%8%37%5%35%5%7%7%33%
2010
April1st to 15thNight
8%8%345%35%5%5%8%41%
1798
16th to endNight
14%7%345%2445%6%40%
1674
May1st to 15thNight
11%6%243245%5%7%45%
1448
16th to endNight
15%5%24335%5%5%8%40%
1497
June1st to 15thNight
12%5%2432445%9%44%
1440
16th to endNight
5%213434447%57%
1440
July1st to 15thNight
32133145%5%9%61%
1440
16th to endNight
3112223447%66%
1512
August1st to 15thNight
5%32322348%62%
1440
16th to endNight
431321236%7%62%
1857
September1st to 15thNight
6%313314348%59%
1800
16th to endNight
11%5%13223346%54%
1885
October1st to 15thNight
13%7%24324446%45%
1941
16th to endNight
9%8%25%5%2435%7%43%
2266
November1st to 15thNight
7%7%35%5%3445%7%46%
2290
16th to endNight
7%7%37%6%45%5%5%8%38%
2520
December1st to 15thNight
7%9%5%9%8%47%5%5%6%30%
2520
16th to endNight
9%10%5%9%7%3445%6%34%
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
45%8%20%19%5%
1433
16th to endDay
45%8%18%19%7%
1536
February1st to 15thDay
50%7%15%19%6%
1512
16th to endDay
54%5%14%18%6%
1572
March1st to 15thDay
41%6%19%23%7%
1800
16th to endDay
50%6%16%23%3
2211
April1st to 15thDay
44%7%17%21%9%
2150
16th to endDay
47%6%15%22%8%
2284
May1st to 15thDay
43%7%12%27%9%
2499
16th to endDay
46%7%15%21%8%
2620
June1st to 15thDay
43%7%16%24%9%
2520
16th to endDay
25%7%20%29%13%2
2520
July1st to 15thDay
23%5%14%31%19%6%
2371
16th to endDay
23%7%13%26%23%4
2489
August1st to 15thDay
26%7%15%26%18%5%
2504
16th to endDay
24%5%9%30%25%4
2343
September1st to 15thDay
29%411%32%17%4
2160
16th to endDay
30%312%30%20%2
1911
October1st to 15thDay
38%6%13%24%15%1
1686
16th to endDay
38%7%17%23%10%1
1595
November1st to 15thDay
36%6%15%25%14%2
1566
16th to endDay
46%6%17%19%8%1
1440
December1st to 15thDay
51%8%16%18%5%
1440
16th to endDay
52%6%18%17%5%
1536
January1st to 15thNight
46%6%17%19%8%
2506
16th to endNight
48%7%16%19%6%1
2688
February1st to 15thNight
50%7%18%16%7%
2361
16th to endNight
44%7%18%21%8%
1902
March1st to 15thNight
40%8%16%25%8%
2160
16th to endNight
47%7%16%22%6%
2010
April1st to 15thNight
38%6%15%25%11%2
1798
16th to endNight
43%6%15%22%11%
1674
May1st to 15thNight
35%7%13%29%13%
1449
16th to endNight
40%8%15%25%10%
1498
June1st to 15thNight
36%7%16%28%10%1
1440
16th to endNight
26%6%17%32%16%1
1440
July1st to 15thNight
18%6%15%35%17%6%
1360
16th to endNight
15%6%13%35%23%5%
1416
August1st to 15thNight
20%5%14%31%21%6%
1432
16th to endNight
20%411%31%24%6%
1857
September1st to 15thNight
23%5%11%32%21%5%
1800
16th to endNight
29%5%12%28%21%2
1885
October1st to 15thNight
39%5%13%23%14%2
1941
16th to endNight
39%5%12%28%12%1
2266
November1st to 15thNight
35%5%14%25%16%2
2290
16th to endNight
41%7%19%20%9%2
2520
December1st to 15thNight
51%7%15%20%5%
2520
16th to endNight
50%5%17%20%6%
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
15%228%28%13%11%
90
16th to endDay
413%33%33%13%2
96
February1st to 15thDay
13%7%52%25%1
90
16th to endDay
13%14%23%34%13%
81
March1st to 15thDay
17%7%42%25%42
90
16th to endDay
16%12%30%26%11%2
249
April1st to 15thDay
14%17%37%20%9%
269
16th to endDay
23%9%24%25%13%2
394
May1st to 15thDay
17%6%26%29%15%4
468
16th to endDay
16%6%24%31%17%2
517
June1st to 15thDay
13%9%30%30%14%1
495
16th to endDay
6%9%33%31%17%1
495
July1st to 15thDay
6%426%40%20%2
475
16th to endDay
5%328%40%20%2
515
August1st to 15thDay
6%326%35%22%5%
493
16th to endDay
8%321%30%30%5%
373
September1st to 15thDay
10%7%25%34%16%5%
315
16th to endDay
13%9%28%25%17%5%
129
October1st to 15thDay
21%7%26%32%5%6%
90
16th to endDay
14%9%30%23%16%5%
96
November1st to 15thDay
10%5%31%25%20%7%
90
16th to endDay
18%10%28%35%6%
90
December1st to 15thDay
20%8%37%23%10%
90
16th to endDay
13%13%43%21%6%1
96
January1st to 15thNight
10%11%40%28%8%
900
16th to endNight
10%12%40%28%6%
960
February1st to 15thNight
11%9%37%26%12%1
777
16th to endNight
8%7%36%32%12%2
632
March1st to 15thNight
9%9%37%32%8%1
720
16th to endNight
15%6%33%34%9%
630
April1st to 15thNight
11%7%36%35%7%
539
16th to endNight
20%8%26%31%13%
540
May1st to 15thNight
14%5%28%36%14%
540
16th to endNight
18%5%25%38%11%
563
June1st to 15thNight
14%6%32%37%9%
540
16th to endNight
7%430%44%13%
540
July1st to 15thNight
2328%50%14%
510
16th to endNight
2327%53%13%
564
August1st to 15thNight
6%225%48%15%1
539
16th to endNight
5%325%42%21%1
573
September1st to 15thNight
8%422%44%19%1
540
16th to endNight
13%328%35%16%1
516
October1st to 15thNight
18%6%32%31%11%
621
16th to endNight
14%6%31%34%12%1
858
November1st to 15thNight
9%10%35%30%12%
875
16th to endNight
9%10%41%29%8%
900
December1st to 15thNight
11%9%37%30%10%
900
16th to endNight
15%10%35%29%9%
960
Page generated at 2017-09-24 07:15:57. Version ac04

Copyright 2017 A. Danko


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