Steamboat Lake State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Steamboat Lake State Park clear sky chart from 2005-11-06 to 2024-11-05.

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	4 11% 4 8% 5% 4 4 4 5% 7% 44%	105320
	Night	4 11% 4 9% 4 4 4 3 5% 6% 46%	102437
Transparency	Day	38% 5% 10% 22% 18% 8%	105072
	Night	37% 5% 11% 23% 17% 6%	102276
Seeing	Day	14% 17% 31% 24% 12% 3	15608
	Night	12% 10% 27% 35% 15% 2	25661

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 16% 7% 18% 9% 4 2 2 4 5% 30%	2538
	11th to 20th	Day	3 19% 11% 15% 9% 4 3 3 4 4 25%	2743
	21st to end	Day	2 23% 13% 13% 4 2 2 2 3 5% 30%	3146
February	1st to 10th	Day	4 23% 8% 15% 7% 4 3 2 4 5% 26%	1710
	11th to 20th	Day	5% 21% 10% 14% 6% 3 3 2 3 4 30%	1698
	21st to end	Day	2 19% 8% 19% 8% 4 3 3 4 4 26%	1570
March	1st to 10th	Day	2 17% 9% 17% 5% 4 3 3 5% 5% 31%	3290
	11th to 20th	Day	1 12% 6% 9% 4 4 3 3 4 6% 48%	3490
	21st to end	Day	4 21% 9% 18% 5% 5% 4 3 5% 6% 21%	3917
April	1st to 10th	Day	5% 19% 4 9% 4 4 5% 3 5% 7% 35%	2280
	11th to 20th	Day	7% 18% 5% 10% 5% 3 5% 4 5% 6% 31%	2251
	21st to end	Day	6% 16% 4 7% 5% 4 4 5% 6% 8% 36%	2280
May	1st to 10th	Day	7% 20% 7% 9% 6% 4 5% 4 5% 6% 27%	4152
	11th to 20th	Day	5% 7% 2 5% 4 5% 6% 5% 8% 10% 42%	4388
	21st to end	Day	7% 10% 3 6% 5% 4 5% 4 6% 8% 44%	4825
June	1st to 10th	Day	6% 5% 2 5% 4 4 4 5% 6% 8% 50%	2660
	11th to 20th	Day	5% 4 2 4 4 3 4 4 5% 8% 57%	2660
	21st to end	Day	3 3 1 5% 4 4 5% 4 6% 7% 60%	2660
July	1st to 10th	Day	4 2 1 3 3 4 4 4 6% 8% 61%	4430
	11th to 20th	Day	2 3 1 5% 4 5% 6% 6% 9% 9% 49%	4430
	21st to end	Day	4 4 2 5% 5% 5% 6% 4 7% 8% 51%	4535
August	1st to 10th	Day	4 5% 2 6% 5% 5% 7% 6% 7% 8% 44%	4092
	11th to 20th	Day	6% 5% 2 6% 5% 5% 5% 4 6% 8% 48%	3940
	21st to end	Day	4 3 2 5% 4 4 5% 4 6% 7% 56%	4180
September	1st to 10th	Day	6% 4 2 5% 3 3 4 3 4 5% 60%	2280
	11th to 20th	Day	7% 6% 2 5% 3 4 3 4 5% 5% 57%	2280
	21st to end	Day	7% 6% 1 5% 3 3 3 3 4 5% 60%	2022
October	1st to 10th	Day	5% 7% 1 3 2 2 2 2 3 4 68%	3170
	11th to 20th	Day	6% 7% 2 5% 4 4 4 4 6% 8% 52%	3150
	21st to end	Day	5% 15% 3 5% 2 2 3 3 4 6% 50%	3438
November	1st to 10th	Day	5% 13% 4 7% 3 3 3 4 5% 6% 47%	1725
	11th to 20th	Day	5% 19% 4 8% 5% 2 3 2 5% 5% 42%	1630
	21st to end	Day	4 14% 4 13% 3 3 2 2 3 6% 46%	1520
December	1st to 10th	Day	5% 20% 7% 14% 4 4 3 3 4 5% 32%	1520
	11th to 20th	Day	4 20% 6% 11% 6% 3 3 2 4 6% 36%	1926
	21st to end	Day	2 18% 7% 15% 6% 4 3 4 4 6% 30%	2794
January	1st to 10th	Night	2 14% 7% 20% 9% 5% 3 3 5% 4 29%	4417
	11th to 20th	Night	2 22% 10% 15% 9% 4 2 2 2 4 29%	4256
	21st to end	Night	2 23% 10% 15% 5% 3 2 2 4 4 32%	4521
February	1st to 10th	Night	3 22% 8% 15% 7% 4 3 3 3 5% 27%	2470
	11th to 20th	Night	4 18% 8% 14% 5% 3 3 2 4 5% 32%	2369
	21st to end	Night	3 18% 8% 15% 6% 3 2 3 4 5% 32%	1884
March	1st to 10th	Night	3 14% 8% 14% 4 3 4 3 4 5% 38%	3564
	11th to 20th	Night	2 12% 4 8% 3 3 3 2 5% 6% 52%	3490
	21st to end	Night	3 18% 6% 12% 5% 5% 5% 3 5% 7% 30%	3719
April	1st to 10th	Night	5% 16% 5% 7% 4 3 4 3 5% 5% 42%	1900
	11th to 20th	Night	7% 14% 4 8% 4 5% 4 4 5% 6% 39%	1877
	21st to end	Night	6% 14% 3 6% 5% 4 3 4 6% 7% 42%	1900
May	1st to 10th	Night	7% 15% 7% 8% 4 4 4 3 5% 6% 36%	2813
	11th to 20th	Night	7% 8% 2 6% 4 5% 5% 5% 7% 9% 43%	2517
	21st to end	Night	6% 9% 2 5% 3 4 4 4 6% 6% 51%	2762
June	1st to 10th	Night	5% 5% 2 3 4 4 4 4 7% 9% 54%	1520
	11th to 20th	Night	5% 4 1 5% 3 4 4 4 5% 6% 57%	1520
	21st to end	Night	3 3 1 3 3 3 3 3 7% 6% 65%	1520
July	1st to 10th	Night	3 2 1 3 3 3 3 3 5% 7% 67%	2540
	11th to 20th	Night	2 2 1 4 4 4 6% 5% 8% 11% 54%	2540
	21st to end	Night	1 2 1 4 4 5% 5% 5% 7% 9% 57%	3011
August	1st to 10th	Night	3 3 1 5% 4 4 5% 5% 7% 9% 53%	2847
	11th to 20th	Night	4 3 2 5% 5% 4 6% 5% 8% 10% 48%	2899
	21st to end	Night	3 3 2 5% 4 5% 5% 4 6% 8% 56%	3487
September	1st to 10th	Night	5% 3 1 3 2 3 3 3 5% 7% 64%	1900
	11th to 20th	Night	6% 5% 1 3 4 4 3 3 4 6% 60%	1900
	21st to end	Night	6% 4 1 3 2 3 2 3 4 5% 67%	2154
October	1st to 10th	Night	5% 5% 1 3 2 2 2 2 3 4 71%	3800
	11th to 20th	Night	5% 7% 1 4 3 3 4 4 6% 7% 56%	3778
	21st to end	Night	5% 10% 4 6% 3 2 3 2 4 7% 55%	4120
November	1st to 10th	Night	6% 12% 3 7% 3 3 2 2 5% 6% 50%	2432
	11th to 20th	Night	6% 16% 4 8% 3 3 4 3 4 5% 45%	2546
	21st to end	Night	3 14% 5% 9% 4 3 3 3 4 7% 44%	2660
December	1st to 10th	Night	4 20% 6% 11% 5% 3 2 3 4 5% 37%	2660
	11th to 20th	Night	4 16% 6% 11% 5% 3 3 2 5% 8% 37%	3271
	21st to end	Night	3 15% 7% 12% 7% 5% 4 3 5% 7% 33%	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	53% 7% 11% 18% 10% 1	2539
	11th to 20th	Day	61% 5% 14% 12% 6% 2	2743
	21st to end	Day	56% 8% 13% 14% 8% 1	3146
February	1st to 10th	Day	60% 6% 11% 15% 8% 1	1710
	11th to 20th	Day	58% 4 10% 18% 7% 2	1707
	21st to end	Day	60% 5% 10% 13% 10% 1	1570
March	1st to 10th	Day	52% 6% 9% 22% 10% 1	3290
	11th to 20th	Day	36% 4 18% 34% 7% 1	3490
	21st to end	Day	59% 7% 8% 20% 4 1	3917
April	1st to 10th	Day	46% 6% 13% 18% 13% 4	2280
	11th to 20th	Day	51% 5% 10% 20% 13% 1	2254
	21st to end	Day	44% 6% 10% 30% 10%	2280
May	1st to 10th	Day	55% 6% 9% 15% 14% 1	4152
	11th to 20th	Day	30% 9% 14% 30% 16% 1	4392
	21st to end	Day	32% 8% 7% 29% 23% 2	4825
June	1st to 10th	Day	28% 6% 12% 25% 23% 7%	2660
	11th to 20th	Day	25% 4 8% 19% 29% 15%	2660
	21st to end	Day	22% 4 6% 21% 32% 16%	2660
July	1st to 10th	Day	19% 4 6% 15% 26% 30%	4361
	11th to 20th	Day	25% 5% 8% 19% 24% 20%	4355
	21st to end	Day	27% 5% 9% 16% 22% 22%	4392
August	1st to 10th	Day	32% 5% 11% 21% 17% 13%	4078
	11th to 20th	Day	32% 4 11% 17% 25% 11%	3979
	21st to end	Day	25% 4 9% 21% 23% 17%	4179
September	1st to 10th	Day	25% 3 6% 18% 27% 20%	2280
	11th to 20th	Day	28% 4 8% 23% 25% 12%	2280
	21st to end	Day	26% 3 6% 29% 29% 6%	2022
October	1st to 10th	Day	22% 3 5% 23% 35% 12%	3170
	11th to 20th	Day	28% 4 8% 35% 21% 3	3150
	21st to end	Day	35% 2 11% 35% 15% 2	3438
November	1st to 10th	Day	36% 6% 11% 28% 18% 1	1725
	11th to 20th	Day	44% 4 15% 22% 14% 1	1630
	21st to end	Day	41% 3 14% 27% 13% 1	1520
December	1st to 10th	Day	54% 4 18% 14% 9% 1	1520
	11th to 20th	Day	49% 4 11% 27% 8%	1924
	21st to end	Day	53% 6% 7% 18% 14% 2	2794
January	1st to 10th	Night	55% 6% 10% 19% 8% 1	4417
	11th to 20th	Night	58% 5% 14% 12% 8% 3	4256
	21st to end	Night	53% 8% 13% 14% 10% 2	4521
February	1st to 10th	Night	58% 8% 10% 16% 8% 1	2470
	11th to 20th	Night	54% 5% 11% 20% 9% 2	2370
	21st to end	Night	53% 5% 10% 18% 12% 3	1884
March	1st to 10th	Night	44% 6% 10% 24% 14% 1	3564
	11th to 20th	Night	32% 5% 17% 31% 12% 3	3490
	21st to end	Night	47% 10% 11% 25% 6% 1	3719
April	1st to 10th	Night	41% 6% 14% 19% 16% 4	1900
	11th to 20th	Night	42% 6% 13% 23% 15% 1	1877
	21st to end	Night	39% 5% 12% 27% 17% 1	1900
May	1st to 10th	Night	44% 8% 9% 21% 15% 3	2813
	11th to 20th	Night	31% 11% 15% 29% 10% 4	2518
	21st to end	Night	30% 7% 8% 32% 22% 2	2762
June	1st to 10th	Night	25% 5% 15% 26% 21% 8%	1520
	11th to 20th	Night	26% 5% 9% 18% 25% 16%	1520
	21st to end	Night	18% 4 5% 23% 30% 20%	1520
July	1st to 10th	Night	17% 5% 7% 15% 25% 31%	2500
	11th to 20th	Night	20% 5% 9% 25% 23% 17%	2492
	21st to end	Night	22% 5% 11% 20% 25% 18%	2917
August	1st to 10th	Night	25% 4 16% 23% 14% 18%	2838
	11th to 20th	Night	29% 7% 15% 15% 22% 12%	2926
	21st to end	Night	25% 4 11% 18% 26% 16%	3487
September	1st to 10th	Night	20% 4 9% 19% 27% 21%	1900
	11th to 20th	Night	26% 3 10% 22% 26% 14%	1900
	21st to end	Night	20% 3 7% 27% 36% 7%	2154
October	1st to 10th	Night	19% 3 5% 20% 40% 14%	3800
	11th to 20th	Night	26% 3 8% 36% 24% 3	3778
	21st to end	Night	31% 3 12% 36% 16% 3	4120
November	1st to 10th	Night	35% 5% 12% 26% 20% 2	2432
	11th to 20th	Night	40% 4 14% 26% 13% 3	2546
	21st to end	Night	40% 5% 10% 29% 15% 2	2660
December	1st to 10th	Night	50% 4 15% 18% 11% 2	2660
	11th to 20th	Night	46% 4 14% 27% 10%	3272
	21st to end	Night	50% 7% 10% 16% 15% 2	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	21% 16% 31% 20% 11% 1	270
	11th to 20th	Day	16% 23% 33% 20% 7%	270
	21st to end	Day	12% 22% 41% 19% 4 1	297
February	1st to 10th	Day	28% 24% 33% 13% 3	270
	11th to 20th	Day	22% 24% 33% 19% 2	270
	21st to end	Day	24% 30% 31% 15% 1	225
March	1st to 10th	Day	23% 23% 32% 17% 6%	365
	11th to 20th	Day	14% 22% 36% 21% 7%	460
	21st to end	Day	19% 27% 36% 14% 3 1	506
April	1st to 10th	Day	22% 26% 30% 18% 4	460
	11th to 20th	Day	23% 27% 30% 16% 2 1	452
	21st to end	Day	17% 21% 34% 18% 8% 2	460
May	1st to 10th	Day	22% 22% 29% 17% 9% 1	491
	11th to 20th	Day	14% 14% 28% 27% 15% 2	675
	21st to end	Day	15% 16% 27% 24% 16% 2	734
June	1st to 10th	Day	8% 13% 27% 29% 18% 5%	680
	11th to 20th	Day	9% 17% 34% 27% 12% 2	680
	21st to end	Day	5% 12% 32% 32% 15% 3	680
July	1st to 10th	Day	7% 6% 23% 35% 24% 5%	671
	11th to 20th	Day	6% 5% 27% 34% 23% 6%	668
	21st to end	Day	6% 8% 24% 34% 23% 5%	586
August	1st to 10th	Day	10% 7% 34% 32% 11% 5%	487
	11th to 20th	Day	6% 10% 34% 32% 14% 5%	477
	21st to end	Day	7% 11% 32% 28% 17% 4	539
September	1st to 10th	Day	8% 12% 30% 27% 18% 6%	490
	11th to 20th	Day	9% 14% 38% 23% 11% 5%	490
	21st to end	Day	10% 16% 28% 25% 14% 6%	366
October	1st to 10th	Day	14% 15% 26% 26% 13% 6%	300
	11th to 20th	Day	16% 17% 31% 23% 10% 3	300
	21st to end	Day	19% 23% 31% 21% 6%	330
November	1st to 10th	Day	20% 22% 29% 21% 8%	282
	11th to 20th	Day	17% 23% 31% 24% 4 1	270
	21st to end	Day	12% 21% 37% 25% 4 1	270
December	1st to 10th	Day	20% 25% 30% 18% 5% 1	270
	11th to 20th	Day	17% 21% 40% 17% 5%	270
	21st to end	Day	23% 20% 34% 16% 6% 1	297
January	1st to 10th	Night	15% 14% 29% 31% 10% 1	950
	11th to 20th	Night	15% 17% 33% 28% 6% 1	841
	21st to end	Night	13% 11% 37% 31% 7% 1	836
February	1st to 10th	Night	17% 12% 40% 24% 6%	760
	11th to 20th	Night	14% 16% 33% 32% 5%	744
	21st to end	Night	14% 19% 38% 26% 4	628
March	1st to 10th	Night	14% 13% 34% 29% 10% 1	760
	11th to 20th	Night	9% 9% 29% 41% 11% 1	760
	21st to end	Night	11% 12% 34% 33% 10% 1	778
April	1st to 10th	Night	15% 12% 31% 36% 6%	570
	11th to 20th	Night	15% 12% 33% 30% 9% 1	563
	21st to end	Night	14% 11% 25% 35% 14% 1	570
May	1st to 10th	Night	16% 7% 32% 31% 13% 2	570
	11th to 20th	Night	12% 4 19% 45% 17% 2	561
	21st to end	Night	11% 6% 25% 38% 19% 2	617
June	1st to 10th	Night	7% 6% 24% 38% 23% 2	570
	11th to 20th	Night	8% 7% 26% 43% 15% 1	570
	21st to end	Night	4 3 19% 45% 27% 2	570
July	1st to 10th	Night	5% 3 13% 38% 38% 3	555
	11th to 20th	Night	4 2 9% 47% 34% 3	552
	21st to end	Night	2 3 8% 42% 42% 4	624
August	1st to 10th	Night	6% 2 7% 48% 35% 2	567
	11th to 20th	Night	4 2 10% 50% 30% 4	564
	21st to end	Night	4 2 10% 45% 33% 6%	627
September	1st to 10th	Night	6% 2 15% 43% 29% 5%	570
	11th to 20th	Night	9% 3 15% 43% 26% 4	570
	21st to end	Night	8% 3 22% 35% 26% 7%	701
October	1st to 10th	Night	11% 6% 25% 35% 20% 3	760
	11th to 20th	Night	12% 9% 24% 39% 14% 2	760
	21st to end	Night	14% 10% 30% 33% 11% 2	836
November	1st to 10th	Night	13% 12% 31% 32% 11% 1	912
	11th to 20th	Night	16% 15% 32% 29% 6% 1	950
	21st to end	Night	12% 11% 33% 35% 8%	950
December	1st to 10th	Night	18% 12% 34% 28% 7%	950
	11th to 20th	Night	15% 14% 36% 30% 5%	950
	21st to end	Night	18% 17% 35% 23% 6% 1	1045

Page generated at 2024-11-03 00:11:11. Version ac07

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