Cold Creek Conservation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cold Creek Conservation Area clear sky chart from 2005-11-06 to 2025-05-11.

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	14% 11% 4 9% 6% 5% 5% 4 5% 7% 30%	114387
	Night	14% 11% 4 9% 6% 5% 5% 4 5% 6% 31%	114487
Transparency	Day	50% 7% 13% 19% 11% 1	118026
	Night	49% 7% 13% 19% 11% 1	119013
Seeing	Day	20% 16% 31% 21% 9% 3	15313
	Night	20% 12% 32% 25% 10% 1	24529

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	12% 12% 4 15% 8% 6% 5% 5% 6% 6% 20%	3597
	11th to 20th	Day	10% 19% 6% 18% 11% 8% 4 4 4 5% 12%	3916
	21st to end	Day	16% 18% 7% 15% 7% 5% 5% 4 4 5% 15%	4466
February	1st to 10th	Day	14% 16% 5% 13% 8% 7% 6% 3 5% 4 19%	1800
	11th to 20th	Day	12% 15% 6% 14% 8% 5% 5% 4 5% 5% 21%	1753
	21st to end	Day	16% 17% 5% 12% 5% 4 6% 3 4 5% 24%	1540
March	1st to 10th	Day	18% 11% 5% 10% 6% 5% 4 3 4 5% 30%	4932
	11th to 20th	Day	11% 13% 4 9% 5% 6% 5% 4 5% 7% 30%	4980
	21st to end	Day	17% 13% 4 9% 5% 4 4 3 4 5% 32%	5465
April	1st to 10th	Day	16% 15% 4 9% 6% 4 4 3 5% 6% 28%	2352
	11th to 20th	Day	18% 11% 3 7% 4 4 4 3 4 6% 35%	2469
	21st to end	Day	20% 9% 3 8% 5% 4 4 3 5% 6% 33%	2600
May	1st to 10th	Day	17% 8% 3 7% 4 4 4 4 6% 8% 34%	4238
	11th to 20th	Day	16% 9% 3 8% 6% 5% 5% 4 5% 8% 31%	4359
	21st to end	Day	12% 5% 2 6% 5% 4 5% 4 6% 7% 45%	4837
June	1st to 10th	Day	14% 7% 3 6% 5% 4 5% 6% 6% 8% 36%	2660
	11th to 20th	Day	12% 5% 2 6% 5% 4 5% 4 7% 10% 40%	2698
	21st to end	Day	14% 5% 2 6% 5% 5% 5% 4 7% 8% 38%	2850
July	1st to 10th	Day	11% 5% 2 6% 5% 6% 6% 5% 7% 10% 38%	4610
	11th to 20th	Day	10% 4 2 5% 5% 5% 6% 4 7% 10% 42%	4440
	21st to end	Day	8% 6% 2 6% 6% 6% 6% 5% 7% 8% 39%	4484
August	1st to 10th	Day	15% 7% 2 6% 5% 4 6% 4 7% 9% 35%	4104
	11th to 20th	Day	10% 7% 3 9% 6% 5% 6% 5% 7% 9% 33%	4044
	21st to end	Day	9% 6% 2 7% 5% 5% 5% 4 6% 10% 40%	4379
September	1st to 10th	Day	13% 7% 2 6% 5% 6% 6% 4 6% 7% 39%	2280
	11th to 20th	Day	11% 6% 2 7% 5% 4 5% 4 5% 8% 44%	2154
	21st to end	Day	15% 6% 3 8% 7% 5% 5% 4 6% 7% 34%	2061
October	1st to 10th	Day	18% 9% 2 8% 5% 5% 4 3 4 7% 33%	1900
	11th to 20th	Day	20% 10% 3 9% 6% 5% 4 3 5% 6% 28%	1900
	21st to end	Day	25% 13% 4 9% 5% 4 5% 3 5% 5% 21%	2090
November	1st to 10th	Day	14% 12% 4 8% 5% 5% 6% 4 6% 7% 29%	1683
	11th to 20th	Day	14% 15% 5% 9% 6% 7% 5% 4 6% 8% 23%	1600
	21st to end	Day	16% 16% 7% 11% 7% 6% 5% 4 5% 6% 18%	1600
December	1st to 10th	Day	19% 19% 6% 13% 7% 6% 5% 3 5% 5% 14%	2600
	11th to 20th	Day	19% 21% 5% 11% 5% 4 5% 3 5% 4 19%	2986
	21st to end	Day	24% 18% 6% 16% 6% 4 4 3 4 4 11%	3960
January	1st to 10th	Night	13% 12% 5% 12% 7% 7% 7% 5% 5% 6% 20%	6349
	11th to 20th	Night	12% 15% 6% 15% 12% 8% 7% 4 5% 5% 12%	5951
	21st to end	Night	14% 14% 6% 12% 8% 6% 5% 4 5% 6% 20%	6490
February	1st to 10th	Night	12% 16% 5% 10% 7% 6% 5% 4 5% 6% 24%	2600
	11th to 20th	Night	13% 14% 5% 11% 8% 6% 6% 4 5% 6% 24%	2533
	21st to end	Night	12% 13% 5% 11% 6% 6% 5% 5% 6% 5% 27%	2084
March	1st to 10th	Night	15% 11% 5% 10% 6% 5% 5% 4 5% 5% 29%	4908
	11th to 20th	Night	9% 10% 3 8% 5% 5% 6% 5% 7% 8% 35%	4979
	21st to end	Night	19% 9% 2 7% 4 4 5% 3 5% 5% 37%	5467
April	1st to 10th	Night	17% 11% 4 9% 5% 5% 4 4 5% 6% 30%	2046
	11th to 20th	Night	15% 10% 2 6% 4 4 4 4 6% 6% 37%	1897
	21st to end	Night	14% 11% 3 6% 5% 4 5% 5% 5% 7% 36%	1800
May	1st to 10th	Night	16% 8% 3 6% 4 5% 4 4 5% 6% 39%	2923
	11th to 20th	Night	15% 8% 2 7% 4 4 5% 4 5% 8% 39%	2538
	21st to end	Night	9% 5% 3 5% 3 4 4 3 6% 8% 51%	2738
June	1st to 10th	Night	12% 6% 2 5% 6% 5% 5% 5% 5% 9% 41%	1520
	11th to 20th	Night	9% 4 2 7% 4 4 5% 5% 6% 10% 43%	1473
	21st to end	Night	11% 5% 2 6% 5% 4 3 3 7% 7% 46%	1330
July	1st to 10th	Night	5% 4 2 6% 5% 4 4 4 6% 10% 50%	2334
	11th to 20th	Night	11% 4 1 5% 4 3 5% 3 5% 7% 52%	2520
	21st to end	Night	6% 4 2 5% 4 5% 5% 4 7% 8% 51%	3052
August	1st to 10th	Night	10% 6% 2 6% 5% 4 4 3 5% 7% 49%	2825
	11th to 20th	Night	10% 5% 3 6% 4 4 3 3 5% 8% 49%	2785
	21st to end	Night	10% 6% 2 5% 4 5% 4 3 6% 9% 46%	3244
September	1st to 10th	Night	8% 5% 2 6% 4 4 5% 4 7% 7% 48%	1900
	11th to 20th	Night	10% 5% 1 4 3 3 4 3 5% 7% 53%	2023
	21st to end	Night	16% 6% 2 7% 5% 4 4 3 5% 7% 40%	2118
October	1st to 10th	Night	17% 7% 2 7% 4 5% 5% 4 6% 6% 38%	2280
	11th to 20th	Night	17% 9% 3 8% 5% 5% 5% 4 5% 6% 34%	2280
	21st to end	Night	20% 10% 3 8% 6% 5% 5% 4 6% 6% 27%	2508
November	1st to 10th	Night	16% 9% 3 8% 5% 5% 4 3 5% 7% 36%	2608
	11th to 20th	Night	15% 13% 3 8% 6% 5% 5% 4 7% 7% 28%	2800
	21st to end	Night	18% 14% 4 9% 6% 5% 5% 4 5% 7% 23%	2800
December	1st to 10th	Night	18% 17% 5% 11% 6% 6% 6% 4 6% 6% 15%	4580
	11th to 20th	Night	14% 20% 6% 11% 6% 5% 5% 4 4 5% 19%	5208
	21st to end	Night	23% 18% 6% 14% 6% 5% 4 3 4 4 13%	6996

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	58% 7% 12% 14% 9%	3598
	11th to 20th	Day	73% 6% 9% 8% 4	3950
	21st to end	Day	70% 6% 10% 8% 6%	4466
February	1st to 10th	Day	63% 10% 9% 14% 4 1	1800
	11th to 20th	Day	60% 9% 11% 13% 6% 1	1762
	21st to end	Day	61% 7% 10% 14% 7% 1	1540
March	1st to 10th	Day	54% 6% 13% 12% 13% 1	4935
	11th to 20th	Day	49% 7% 15% 19% 7% 2	4980
	21st to end	Day	52% 6% 9% 18% 13% 2	5465
April	1st to 10th	Day	55% 6% 10% 17% 10% 1	2352
	11th to 20th	Day	49% 6% 11% 20% 14% 1	2469
	21st to end	Day	50% 7% 12% 17% 12% 2	2600
May	1st to 10th	Day	45% 9% 13% 18% 13% 1	4250
	11th to 20th	Day	47% 12% 14% 19% 8% 1	4363
	21st to end	Day	34% 10% 14% 22% 18% 3	4837
June	1st to 10th	Day	42% 9% 12% 20% 14% 1	2660
	11th to 20th	Day	36% 9% 15% 23% 15% 1	2698
	21st to end	Day	40% 9% 14% 23% 13% 1	2850
July	1st to 10th	Day	39% 5% 15% 24% 15% 2	4540
	11th to 20th	Day	34% 6% 13% 35% 11% 1	4365
	21st to end	Day	38% 7% 15% 21% 17% 1	4341
August	1st to 10th	Day	44% 7% 14% 21% 13% 1	4091
	11th to 20th	Day	43% 7% 16% 23% 10%	4083
	21st to end	Day	38% 6% 13% 32% 10% 1	4379
September	1st to 10th	Day	40% 9% 15% 25% 10% 1	2280
	11th to 20th	Day	35% 8% 15% 28% 13%	2154
	21st to end	Day	46% 9% 13% 24% 8%	2061
October	1st to 10th	Day	43% 5% 12% 26% 14% 1	3160
	11th to 20th	Day	41% 5% 14% 25% 15%	3140
	21st to end	Day	57% 5% 13% 19% 6%	3428
November	1st to 10th	Day	49% 10% 14% 18% 9% 1	1683
	11th to 20th	Day	55% 10% 14% 13% 8%	1600
	21st to end	Day	62% 9% 14% 12% 2	1600
December	1st to 10th	Day	70% 6% 14% 7% 3	2600
	11th to 20th	Day	65% 8% 12% 8% 7%	2986
	21st to end	Day	75% 6% 6% 7% 6%	3960
January	1st to 10th	Night	57% 7% 12% 19% 5%	6349
	11th to 20th	Night	67% 10% 9% 10% 4	5992
	21st to end	Night	62% 9% 10% 9% 10% 1	6490
February	1st to 10th	Night	57% 9% 12% 17% 5%	2600
	11th to 20th	Night	58% 8% 11% 16% 8%	2535
	21st to end	Night	53% 8% 14% 17% 8%	2084
March	1st to 10th	Night	53% 7% 12% 15% 11% 2	4918
	11th to 20th	Night	41% 7% 19% 22% 9% 2	4980
	21st to end	Night	46% 5% 10% 20% 17% 2	5467
April	1st to 10th	Night	53% 6% 11% 17% 12% 2	2046
	11th to 20th	Night	45% 8% 10% 20% 15% 2	1897
	21st to end	Night	45% 7% 13% 17% 16% 2	1800
May	1st to 10th	Night	42% 9% 13% 16% 16% 3	2930
	11th to 20th	Night	41% 11% 14% 21% 10% 2	2539
	21st to end	Night	29% 8% 16% 23% 22% 2	2739
June	1st to 10th	Night	37% 8% 13% 23% 17% 2	1520
	11th to 20th	Night	34% 8% 13% 23% 20% 2	1473
	21st to end	Night	36% 7% 14% 25% 17% 1	1330
July	1st to 10th	Night	29% 5% 15% 25% 21% 4	2295
	11th to 20th	Night	31% 4 13% 35% 16% 1	2472
	21st to end	Night	30% 7% 15% 31% 15% 2	2955
August	1st to 10th	Night	36% 4 14% 29% 15% 2	2814
	11th to 20th	Night	34% 5% 16% 32% 12% 1	2812
	21st to end	Night	36% 5% 12% 33% 13% 1	3244
September	1st to 10th	Night	32% 9% 15% 28% 14% 1	1900
	11th to 20th	Night	29% 8% 12% 33% 18%	2023
	21st to end	Night	42% 8% 13% 26% 11%	2118
October	1st to 10th	Night	34% 5% 8% 28% 24% 1	3800
	11th to 20th	Night	41% 5% 14% 26% 13%	3779
	21st to end	Night	42% 6% 16% 25% 10%	4120
November	1st to 10th	Night	45% 7% 16% 21% 10% 1	2608
	11th to 20th	Night	51% 9% 15% 16% 8% 1	2800
	21st to end	Night	57% 10% 17% 13% 3	2800
December	1st to 10th	Night	66% 6% 14% 11% 3	4580
	11th to 20th	Night	64% 7% 10% 10% 7%	5208
	21st to end	Night	71% 8% 8% 8% 5%	6996

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	22% 23% 33% 19% 4 1	200
	11th to 20th	Day	25% 26% 30% 13% 4	277
	21st to end	Day	26% 25% 32% 15% 2	330
February	1st to 10th	Day	31% 27% 29% 10% 2	300
	11th to 20th	Day	26% 30% 36% 7% 1	300
	21st to end	Day	38% 24% 29% 9%	254
March	1st to 10th	Day	23% 21% 34% 16% 5%	500
	11th to 20th	Day	24% 20% 37% 15% 4	500
	21st to end	Day	31% 19% 31% 14% 5% 1	550
April	1st to 10th	Day	25% 21% 34% 14% 5%	500
	11th to 20th	Day	30% 22% 26% 13% 7% 2	492
	21st to end	Day	26% 17% 36% 13% 6% 2	500
May	1st to 10th	Day	24% 14% 32% 19% 8% 3	503
	11th to 20th	Day	17% 15% 29% 24% 12% 3	487
	21st to end	Day	15% 12% 28% 29% 12% 5%	529
June	1st to 10th	Day	14% 17% 31% 28% 9% 2	490
	11th to 20th	Day	16% 13% 30% 27% 12% 2	528
	21st to end	Day	16% 10% 34% 28% 8% 3	680
July	1st to 10th	Day	10% 8% 32% 31% 16% 4	590
	11th to 20th	Day	12% 8% 29% 30% 15% 7%	484
	21st to end	Day	10% 7% 32% 32% 13% 7%	532
August	1st to 10th	Day	13% 8% 26% 28% 17% 9%	486
	11th to 20th	Day	10% 6% 28% 27% 20% 9%	479
	21st to end	Day	13% 8% 28% 25% 19% 6%	539
September	1st to 10th	Day	14% 8% 28% 27% 13% 9%	490
	11th to 20th	Day	9% 8% 24% 24% 21% 13%	490
	21st to end	Day	16% 11% 30% 22% 15% 6%	490
October	1st to 10th	Day	21% 15% 27% 20% 13% 4	490
	11th to 20th	Day	20% 20% 35% 18% 6% 2	490
	21st to end	Day	31% 19% 28% 18% 4	539
November	1st to 10th	Day	24% 22% 28% 18% 7% 1	274
	11th to 20th	Day	26% 24% 32% 15% 4 1	200
	21st to end	Day	26% 22% 41% 11% 1	200
December	1st to 10th	Day	32% 22% 30% 16% 2	200
	11th to 20th	Day	30% 26% 28% 15% 2 1	200
	21st to end	Day	31% 23% 32% 10% 3	220
January	1st to 10th	Night	23% 21% 35% 16% 4	800
	11th to 20th	Night	26% 18% 33% 20% 3	800
	21st to end	Night	20% 13% 39% 22% 6%	880
February	1st to 10th	Night	20% 20% 39% 19% 2	800
	11th to 20th	Night	22% 19% 38% 17% 3	783
	21st to end	Night	20% 20% 38% 18% 3	660
March	1st to 10th	Night	21% 19% 36% 21% 3	800
	11th to 20th	Night	21% 19% 34% 20% 5%	800
	21st to end	Night	22% 15% 35% 21% 6%	880
April	1st to 10th	Night	25% 14% 37% 21% 3	800
	11th to 20th	Night	19% 15% 36% 21% 8% 1	713
	21st to end	Night	21% 11% 33% 28% 8%	600
May	1st to 10th	Night	19% 7% 31% 31% 11% 2	600
	11th to 20th	Night	16% 8% 32% 33% 11% 1	400
	21st to end	Night	10% 7% 30% 36% 16%	411
June	1st to 10th	Night	13% 7% 33% 34% 12% 1	380
	11th to 20th	Night	11% 9% 30% 36% 14%	380
	21st to end	Night	12% 5% 29% 39% 14%	380
July	1st to 10th	Night	7% 4 26% 43% 20% 1	370
	11th to 20th	Night	11% 3 29% 36% 19% 2	368
	21st to end	Night	7% 3 26% 42% 20% 2	602
August	1st to 10th	Night	11% 1 20% 42% 25% 1	567
	11th to 20th	Night	8% 4 20% 41% 25% 2	564
	21st to end	Night	13% 3 26% 32% 23% 2	695
September	1st to 10th	Night	12% 7% 27% 32% 19% 4	760
	11th to 20th	Night	13% 4 24% 29% 25% 5%	760
	21st to end	Night	19% 7% 22% 31% 18% 4	760
October	1st to 10th	Night	20% 9% 29% 25% 15% 2	760
	11th to 20th	Night	21% 13% 33% 23% 9% 1	760
	21st to end	Night	25% 14% 33% 24% 4	836
November	1st to 10th	Night	23% 13% 32% 24% 8% 1	780
	11th to 20th	Night	22% 18% 32% 21% 6% 1	800
	21st to end	Night	25% 15% 33% 22% 4	800
December	1st to 10th	Night	28% 17% 36% 15% 4	800
	11th to 20th	Night	23% 18% 39% 17% 3	800
	21st to end	Night	32% 15% 33% 17% 3	880

Page generated at 2025-05-08 09:33:59. Version ac07

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