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 2005-11-06 to 2024-11-25.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	8% 7% 3 6% 4 4 4 4 6% 8% 46%	105537
	Night	7% 7% 3 7% 5% 4 5% 4 6% 7% 45%	102631
Transparency	Day	36% 6% 14% 27% 14% 2	105283
	Night	37% 6% 14% 27% 14% 2	102475
Seeing	Day	12% 9% 30% 30% 16% 3	16142
	Night	11% 8% 34% 36% 11% 1	26139

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	3 9% 4 8% 7% 6% 6% 5% 8% 8% 37%	2538
	11th to 20th	Day	2 7% 3 13% 7% 6% 8% 6% 9% 12% 28%	2540
	21st to end	Day	3 10% 3 9% 5% 5% 4 4 6% 9% 42%	2794
February	1st to 10th	Day	7% 13% 5% 10% 7% 5% 4 4 6% 7% 32%	1610
	11th to 20th	Day	5% 13% 5% 11% 6% 5% 5% 4 6% 7% 31%	1745
	21st to end	Day	4 12% 5% 11% 7% 5% 5% 4 6% 8% 34%	1570
March	1st to 10th	Day	5% 8% 4 10% 6% 4 4 3 5% 7% 44%	3130
	11th to 20th	Day	6% 8% 3 8% 5% 5% 5% 5% 7% 10% 38%	3250
	21st to end	Day	15% 17% 6% 10% 5% 4 4 4 5% 7% 25%	4165
April	1st to 10th	Day	10% 9% 4 7% 6% 5% 4 4 6% 9% 37%	2280
	11th to 20th	Day	12% 11% 4 10% 6% 5% 6% 4 6% 5% 32%	2257
	21st to end	Day	14% 8% 3 6% 5% 4 4 5% 6% 8% 38%	2470
May	1st to 10th	Day	16% 9% 2 6% 4 4 5% 4 5% 6% 38%	4399
	11th to 20th	Day	9% 5% 2 6% 5% 5% 5% 4 7% 9% 43%	4388
	21st to end	Day	13% 6% 2 5% 4 5% 5% 3 6% 9% 43%	4825
June	1st to 10th	Day	13% 5% 2 5% 4 4 4 4 7% 8% 44%	2660
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 5% 6% 8% 43%	2660
	21st to end	Day	6% 3 1 4 4 4 5% 3 7% 10% 54%	2660
July	1st to 10th	Day	5% 3 1 5% 5% 5% 6% 5% 6% 9% 51%	4430
	11th to 20th	Day	4 2 1 3 3 3 4 3 6% 7% 64%	4430
	21st to end	Day	4 3 1 4 4 4 4 3 6% 9% 58%	4802
August	1st to 10th	Day	10% 4 1 4 3 3 4 3 5% 7% 58%	4411
	11th to 20th	Day	9% 5% 2 6% 4 4 4 4 6% 8% 49%	4151
	21st to end	Day	7% 3 1 4 3 2 3 3 5% 7% 62%	4180
September	1st to 10th	Day	8% 5% 2 5% 2 3 3 2 5% 7% 59%	2280
	11th to 20th	Day	10% 4 2 4 3 3 3 3 5% 9% 54%	2213
	21st to end	Day	12% 5% 2 4 3 3 3 2 4 6% 57%	2090
October	1st to 10th	Day	8% 4 2 3 3 3 3 3 5% 5% 61%	3268
	11th to 20th	Day	7% 6% 3 5% 4 3 3 3 4 8% 53%	3024
	21st to end	Day	8% 7% 3 5% 3 4 4 3 5% 7% 50%	3091
November	1st to 10th	Day	10% 11% 4 6% 4 4 4 4 5% 6% 41%	1763
	11th to 20th	Day	5% 10% 3 8% 5% 5% 4 4 6% 9% 41%	1671
	21st to end	Day	6% 8% 4 9% 5% 7% 6% 4 7% 7% 38%	1552
December	1st to 10th	Day	5% 13% 4 9% 7% 5% 5% 4 7% 8% 32%	1520
	11th to 20th	Day	5% 10% 4 9% 3 5% 5% 4 6% 8% 41%	1926
	21st to end	Day	5% 9% 4 9% 5% 5% 5% 5% 5% 7% 42%	2794
January	1st to 10th	Night	3 9% 4 10% 6% 6% 6% 5% 7% 7% 37%	4417
	11th to 20th	Night	3 8% 4 10% 7% 8% 10% 5% 7% 8% 30%	4430
	21st to end	Night	3 9% 5% 11% 5% 5% 7% 5% 6% 7% 38%	4873
February	1st to 10th	Night	6% 12% 4 9% 7% 6% 6% 5% 6% 6% 32%	2585
	11th to 20th	Night	5% 11% 4 10% 6% 5% 6% 4 7% 8% 35%	2320
	21st to end	Night	5% 11% 3 9% 6% 4 5% 4 6% 8% 39%	1884
March	1st to 10th	Night	8% 9% 3 7% 5% 4 4 4 6% 6% 44%	3734
	11th to 20th	Night	5% 6% 2 7% 4 4 4 4 7% 10% 47%	3718
	21st to end	Night	15% 15% 7% 11% 4 4 5% 4 5% 6% 24%	3477
April	1st to 10th	Night	9% 9% 3 6% 5% 3 5% 5% 7% 7% 41%	1900
	11th to 20th	Night	11% 10% 4 8% 4 4 5% 5% 6% 7% 36%	1870
	21st to end	Night	13% 7% 2 6% 4 5% 4 4 5% 7% 45%	1710
May	1st to 10th	Night	13% 7% 2 6% 3 5% 4 3 6% 6% 46%	2555
	11th to 20th	Night	13% 6% 2 6% 4 5% 5% 4 6% 8% 40%	2517
	21st to end	Night	15% 6% 2 4 4 4 4 4 6% 7% 44%	2762
June	1st to 10th	Night	11% 5% 2 4 3 3 5% 3 7% 8% 49%	1520
	11th to 20th	Night	10% 4 2 5% 4 4 4 4 5% 8% 48%	1520
	21st to end	Night	5% 3 1 5% 3 3 4 3 5% 7% 59%	1520
July	1st to 10th	Night	5% 4 1 5% 3 3 4 4 8% 10% 52%	2540
	11th to 20th	Night	3 2 1 3 3 3 4 4 5% 8% 64%	2540
	21st to end	Night	4 3 1 3 3 3 4 4 6% 7% 63%	2761
August	1st to 10th	Night	7% 4 1 4 3 3 4 3 5% 7% 59%	2528
	11th to 20th	Night	6% 3 2 5% 4 4 4 4 7% 10% 52%	2685
	21st to end	Night	8% 3 1 4 3 3 3 4 5% 7% 57%	3487
September	1st to 10th	Night	7% 2 2 3 3 2 3 3 5% 7% 64%	1900
	11th to 20th	Night	10% 4 1 5% 3 3 3 3 5% 8% 55%	1966
	21st to end	Night	12% 5% 2 4 3 3 3 3 4 7% 54%	2090
October	1st to 10th	Night	9% 6% 2 4 3 2 3 2 5% 7% 58%	3695
	11th to 20th	Night	7% 7% 2 5% 3 3 4 3 5% 8% 52%	3873
	21st to end	Night	9% 6% 3 7% 4 4 4 3 6% 7% 47%	4467
November	1st to 10th	Night	9% 8% 3 6% 5% 4 4 4 6% 7% 44%	2535
	11th to 20th	Night	6% 10% 4 9% 6% 5% 4 3 5% 8% 42%	2725
	21st to end	Night	5% 7% 4 8% 6% 4 5% 4 6% 8% 43%	2723
December	1st to 10th	Night	5% 10% 4 11% 7% 6% 6% 4 6% 7% 34%	2660
	11th to 20th	Night	5% 9% 4 9% 6% 5% 4 4 6% 7% 42%	3271
	21st to end	Night	6% 9% 4 10% 5% 5% 4 4 5% 5% 43%	4873

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	42% 7% 22% 24% 5%	2539
	11th to 20th	Day	47% 8% 14% 17% 13% 1	2540
	21st to end	Day	40% 7% 16% 28% 7%	2794
February	1st to 10th	Day	51% 6% 12% 21% 10%	1610
	11th to 20th	Day	51% 8% 14% 18% 8% 1	1754
	21st to end	Day	47% 5% 14% 20% 12% 1	1570
March	1st to 10th	Day	39% 7% 12% 29% 13%	3130
	11th to 20th	Day	39% 9% 22% 24% 7%	3250
	21st to end	Day	58% 6% 14% 15% 6%	4165
April	1st to 10th	Day	42% 8% 16% 21% 12% 1	2280
	11th to 20th	Day	51% 7% 13% 20% 9%	2260
	21st to end	Day	43% 7% 15% 25% 9% 1	2470
May	1st to 10th	Day	44% 8% 13% 22% 12% 2	4399
	11th to 20th	Day	34% 9% 14% 32% 10% 1	4392
	21st to end	Day	36% 8% 18% 29% 8%	4825
June	1st to 10th	Day	37% 8% 17% 26% 11% 1	2660
	11th to 20th	Day	36% 8% 15% 27% 11% 3	2660
	21st to end	Day	25% 8% 20% 29% 16% 2	2660
July	1st to 10th	Day	27% 8% 17% 29% 16% 3	4361
	11th to 20th	Day	18% 5% 10% 31% 29% 7%	4355
	21st to end	Day	22% 6% 10% 31% 27% 4	4651
August	1st to 10th	Day	27% 6% 10% 31% 18% 8%	4396
	11th to 20th	Day	32% 6% 14% 32% 13% 2	4193
	21st to end	Day	23% 4 11% 37% 24% 2	4179
September	1st to 10th	Day	27% 4 10% 32% 21% 6%	2280
	11th to 20th	Day	28% 6% 13% 31% 18% 3	2213
	21st to end	Day	31% 4 11% 31% 20% 3	2090
October	1st to 10th	Day	26% 4 8% 29% 27% 6%	3268
	11th to 20th	Day	31% 4 10% 37% 18% 1	3024
	21st to end	Day	34% 5% 11% 31% 17% 2	3091
November	1st to 10th	Day	43% 5% 12% 23% 14% 2	1763
	11th to 20th	Day	38% 6% 17% 25% 12% 2	1671
	21st to end	Day	43% 7% 19% 22% 8% 1	1552
December	1st to 10th	Day	48% 6% 14% 23% 9%	1520
	11th to 20th	Day	40% 6% 22% 28% 4	1924
	21st to end	Day	40% 6% 11% 29% 13% 1	2794
January	1st to 10th	Night	42% 8% 17% 22% 11% 1	4417
	11th to 20th	Night	49% 5% 15% 20% 9% 1	4430
	21st to end	Night	43% 7% 17% 25% 7%	4873
February	1st to 10th	Night	50% 7% 16% 17% 10%	2585
	11th to 20th	Night	45% 7% 15% 22% 9% 1	2321
	21st to end	Night	42% 6% 15% 23% 12% 2	1884
March	1st to 10th	Night	38% 7% 11% 31% 13%	3734
	11th to 20th	Night	30% 8% 19% 31% 11%	3718
	21st to end	Night	60% 7% 13% 14% 6% 1	3477
April	1st to 10th	Night	39% 8% 14% 24% 14% 2	1900
	11th to 20th	Night	44% 7% 13% 23% 12% 1	1870
	21st to end	Night	39% 6% 15% 29% 11%	1710
May	1st to 10th	Night	36% 8% 13% 27% 12% 4	2555
	11th to 20th	Night	37% 10% 17% 26% 9%	2518
	21st to end	Night	37% 9% 16% 26% 11%	2762
June	1st to 10th	Night	31% 7% 15% 30% 14% 2	1520
	11th to 20th	Night	34% 9% 17% 26% 13% 2	1520
	21st to end	Night	24% 7% 18% 32% 17% 2	1520
July	1st to 10th	Night	24% 7% 21% 35% 10% 3	2500
	11th to 20th	Night	18% 5% 10% 30% 29% 7%	2492
	21st to end	Night	20% 5% 11% 36% 22% 6%	2674
August	1st to 10th	Night	25% 5% 10% 30% 21% 9%	2520
	11th to 20th	Night	26% 6% 19% 30% 15% 3	2709
	21st to end	Night	25% 5% 10% 32% 23% 5%	3487
September	1st to 10th	Night	21% 5% 9% 33% 25% 7%	1900
	11th to 20th	Night	28% 6% 14% 29% 20% 4	1966
	21st to end	Night	31% 5% 12% 28% 23% 2	2090
October	1st to 10th	Night	28% 4 8% 25% 28% 7%	3695
	11th to 20th	Night	31% 4 8% 37% 19% 1	3873
	21st to end	Night	37% 4 11% 29% 17% 3	4467
November	1st to 10th	Night	38% 7% 13% 24% 16% 2	2535
	11th to 20th	Night	41% 4 15% 27% 10% 2	2725
	21st to end	Night	38% 7% 20% 24% 10% 1	2723
December	1st to 10th	Night	47% 7% 16% 20% 9% 1	2660
	11th to 20th	Night	41% 7% 19% 25% 8%	3272
	21st to end	Night	43% 5% 10% 26% 14% 1	4873

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	10% 9% 36% 26% 14% 4	270
	11th to 20th	Day	7% 13% 44% 24% 10% 2	270
	21st to end	Day	9% 14% 38% 28% 9% 1	297
February	1st to 10th	Day	12% 10% 42% 32% 4	270
	11th to 20th	Day	12% 10% 38% 31% 8% 1	270
	21st to end	Day	7% 13% 43% 28% 8% 1	225
March	1st to 10th	Day	18% 11% 37% 22% 9% 3	270
	11th to 20th	Day	14% 9% 36% 27% 11% 4	303
	21st to end	Day	14% 11% 31% 27% 13% 3	506
April	1st to 10th	Day	14% 15% 35% 27% 8% 1	460
	11th to 20th	Day	19% 16% 36% 21% 5% 2	458
	21st to end	Day	18% 9% 26% 31% 15% 1	650
May	1st to 10th	Day	17% 8% 26% 30% 15% 4	653
	11th to 20th	Day	16% 7% 23% 31% 18% 5%	675
	21st to end	Day	16% 8% 26% 27% 18% 5%	734
June	1st to 10th	Day	13% 9% 26% 29% 19% 4	680
	11th to 20th	Day	11% 10% 35% 29% 12% 3	680
	21st to end	Day	7% 6% 30% 33% 20% 3	680
July	1st to 10th	Day	6% 5% 23% 39% 23% 4	671
	11th to 20th	Day	7% 6% 26% 40% 19% 4	668
	21st to end	Day	6% 2 25% 39% 23% 5%	739
August	1st to 10th	Day	8% 4 21% 37% 24% 5%	676
	11th to 20th	Day	8% 4 23% 36% 24% 6%	636
	21st to end	Day	9% 6% 24% 31% 23% 7%	539
September	1st to 10th	Day	9% 6% 32% 29% 18% 6%	490
	11th to 20th	Day	11% 8% 24% 36% 17% 4	423
	21st to end	Day	16% 8% 32% 26% 14% 4	300
October	1st to 10th	Day	21% 7% 21% 27% 20% 5%	300
	11th to 20th	Day	11% 12% 35% 26% 14% 3	300
	21st to end	Day	15% 15% 35% 23% 10% 2	330
November	1st to 10th	Day	14% 12% 37% 20% 14% 2	300
	11th to 20th	Day	12% 14% 34% 29% 10% 2	300
	21st to end	Day	9% 12% 37% 33% 9%	282
December	1st to 10th	Day	10% 11% 39% 28% 11% 1	270
	11th to 20th	Day	12% 10% 43% 27% 7% 1	270
	21st to end	Day	5% 13% 39% 30% 12% 1	297
January	1st to 10th	Night	8% 10% 42% 29% 10% 1	950
	11th to 20th	Night	10% 14% 38% 29% 9% 1	950
	21st to end	Night	10% 11% 39% 32% 8%	1045
February	1st to 10th	Night	11% 10% 37% 31% 10% 1	875
	11th to 20th	Night	8% 10% 41% 31% 9% 1	744
	21st to end	Night	8% 7% 36% 35% 11% 3	628
March	1st to 10th	Night	11% 12% 37% 34% 7% 1	760
	11th to 20th	Night	11% 7% 39% 34% 9% 1	751
	21st to end	Night	15% 7% 31% 36% 11%	627
April	1st to 10th	Night	13% 10% 35% 35% 8%	570
	11th to 20th	Night	15% 11% 36% 29% 7% 1	563
	21st to end	Night	16% 7% 28% 36% 12%	570
May	1st to 10th	Night	11% 6% 27% 41% 15% 1	570
	11th to 20th	Night	14% 4 27% 39% 15%	561
	21st to end	Night	19% 6% 25% 37% 12% 1	617
June	1st to 10th	Night	11% 8% 31% 36% 13% 1	570
	11th to 20th	Night	12% 7% 32% 36% 11% 1	570
	21st to end	Night	6% 5% 30% 44% 14% 1	570
July	1st to 10th	Night	4 3 32% 45% 15%	555
	11th to 20th	Night	5% 5% 30% 50% 11%	552
	21st to end	Night	2 2 29% 51% 14%	624
August	1st to 10th	Night	7% 4 24% 48% 16% 1	567
	11th to 20th	Night	6% 3 24% 46% 20% 1	564
	21st to end	Night	8% 4 27% 43% 18% 1	627
September	1st to 10th	Night	8% 3 22% 48% 18% 1	570
	11th to 20th	Night	11% 5% 26% 43% 14% 1	570
	21st to end	Night	14% 5% 32% 36% 13% 1	570
October	1st to 10th	Night	17% 8% 29% 34% 13% 1	694
	11th to 20th	Night	13% 9% 28% 37% 11% 1	817
	21st to end	Night	14% 10% 36% 29% 11% 1	1045
November	1st to 10th	Night	12% 9% 35% 34% 9% 1	975
	11th to 20th	Night	10% 10% 41% 30% 10%	1000
	21st to end	Night	8% 12% 39% 33% 8%	973
December	1st to 10th	Night	9% 9% 41% 32% 9%	950
	11th to 20th	Night	11% 12% 36% 33% 7% 1	950
	21st to end	Night	16% 10% 36% 28% 10%	1045

Page generated at 2024-11-22 06:02:27. Version ac07

Copyright © 2024 Attilla Danko.