Dana-Jowsey Lakes Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dana-Jowsey Lakes Provincial Park clear sky chart from 2005-11-06 to 2025-04-11.

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	16% 13% 5% 10% 6% 5% 5% 3 5% 6% 26%	112964
	Night	15% 15% 5% 12% 6% 5% 5% 3 5% 5% 23%	115470
Transparency	Day	58% 5% 11% 18% 7% 1	116442
	Night	62% 5% 9% 16% 7% 1	120143
Seeing	Day	25% 15% 32% 20% 7% 2	15839
	Night	24% 12% 31% 24% 8% 1	25168

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	8% 20% 10% 21% 8% 8% 5% 3 4 3 9%	3158
	11th to 20th	Day	6% 15% 8% 19% 8% 6% 6% 4 7% 4 16%	3246
	21st to end	Day	7% 18% 9% 16% 7% 8% 8% 4 5% 4 13%	3982
February	1st to 10th	Day	8% 14% 6% 12% 9% 8% 9% 4 6% 7% 19%	1796
	11th to 20th	Day	9% 20% 5% 10% 7% 7% 5% 5% 6% 7% 19%	1753
	21st to end	Day	9% 19% 6% 12% 8% 7% 6% 4 5% 5% 20%	1570
March	1st to 10th	Day	13% 18% 4 10% 7% 5% 5% 4 5% 6% 23%	4655
	11th to 20th	Day	14% 17% 6% 12% 8% 6% 4 3 4 5% 21%	4980
	21st to end	Day	14% 18% 5% 12% 5% 5% 5% 2 4 4 24%	5465
April	1st to 10th	Day	19% 17% 6% 12% 5% 3 3 3 4 6% 23%	2414
	11th to 20th	Day	19% 14% 4 8% 5% 4 3 3 5% 6% 28%	2442
	21st to end	Day	19% 12% 4 8% 4 4 3 3 4 5% 32%	2470
May	1st to 10th	Day	18% 11% 3 7% 5% 5% 5% 4 5% 6% 32%	4189
	11th to 20th	Day	14% 10% 4 8% 5% 5% 5% 4 6% 7% 32%	4453
	21st to end	Day	18% 10% 3 6% 4 4 4 4 4 7% 35%	5185
June	1st to 10th	Day	21% 9% 3 6% 4 5% 5% 4 6% 7% 29%	2850
	11th to 20th	Day	17% 8% 3 7% 5% 4 4 3 5% 8% 36%	2850
	21st to end	Day	20% 10% 2 7% 5% 5% 4 4 5% 7% 30%	2850
July	1st to 10th	Day	19% 8% 3 7% 5% 5% 5% 4 7% 8% 30%	4760
	11th to 20th	Day	14% 8% 2 6% 5% 4 5% 4 6% 8% 37%	4760
	21st to end	Day	18% 7% 2 6% 5% 4 4 4 5% 7% 37%	5019
August	1st to 10th	Day	13% 7% 3 7% 5% 5% 5% 4 7% 9% 37%	4139
	11th to 20th	Day	18% 7% 3 7% 4 4 4 3 5% 6% 38%	4044
	21st to end	Day	17% 6% 2 7% 4 4 4 4 6% 9% 37%	4532
September	1st to 10th	Day	20% 7% 2 8% 4 5% 4 4 5% 8% 33%	2316
	11th to 20th	Day	23% 10% 3 6% 4 4 3 3 5% 6% 32%	2090
	21st to end	Day	24% 12% 3 7% 5% 3 4 2 4 6% 32%	2090
October	1st to 10th	Day	23% 14% 4 7% 4 4 3 2 5% 5% 28%	1929
	11th to 20th	Day	25% 22% 5% 7% 4 4 3 3 4 4 19%	1900
	21st to end	Day	24% 25% 7% 10% 5% 3 3 3 3 4 14%	1895
November	1st to 10th	Day	21% 21% 6% 11% 4 4 3 2 4 4 18%	1618
	11th to 20th	Day	19% 24% 7% 14% 7% 5% 3 3 3 3 12%	1600
	21st to end	Day	19% 25% 6% 16% 7% 5% 4 3 3 3 9%	1587
December	1st to 10th	Day	14% 19% 10% 25% 11% 3 4 2 2 3 6%	2280
	11th to 20th	Day	12% 18% 6% 16% 8% 7% 5% 3 3 4 18%	2621
	21st to end	Day	19% 22% 9% 15% 7% 3 3 4 5% 4 10%	3476
January	1st to 10th	Night	8% 19% 10% 19% 9% 10% 6% 3 4 3 10%	6808
	11th to 20th	Night	9% 16% 7% 17% 10% 7% 6% 5% 6% 4 12%	6657
	21st to end	Night	7% 16% 10% 16% 7% 6% 7% 4 5% 5% 18%	6996
February	1st to 10th	Night	8% 13% 5% 12% 11% 7% 7% 5% 6% 6% 20%	2602
	11th to 20th	Night	9% 16% 6% 15% 8% 6% 5% 4 6% 6% 20%	2533
	21st to end	Night	10% 17% 6% 14% 7% 7% 6% 4 5% 5% 19%	2058
March	1st to 10th	Night	17% 17% 5% 12% 5% 4 5% 3 4 5% 25%	5184
	11th to 20th	Night	16% 19% 6% 14% 7% 4 3 2 3 4 22%	4979
	21st to end	Night	14% 15% 6% 12% 6% 5% 5% 3 4 6% 23%	5467
April	1st to 10th	Night	19% 15% 5% 9% 5% 4 4 3 5% 5% 26%	2001
	11th to 20th	Night	19% 12% 4 10% 4 5% 3 3 5% 5% 30%	1693
	21st to end	Night	18% 12% 4 7% 4 4 3 3 5% 6% 34%	1710
May	1st to 10th	Night	19% 10% 3 7% 5% 4 4 3 5% 5% 34%	2751
	11th to 20th	Night	13% 9% 3 8% 5% 5% 5% 5% 6% 6% 35%	2439
	21st to end	Night	16% 8% 2 7% 5% 4 4 4 7% 6% 37%	2402
June	1st to 10th	Night	22% 10% 3 6% 4 4 4 3 4 7% 33%	1330
	11th to 20th	Night	16% 8% 2 8% 5% 4 4 3 6% 6% 37%	1330
	21st to end	Night	19% 9% 2 5% 4 4 3 5% 5% 9% 35%	1330
July	1st to 10th	Night	16% 7% 2 6% 4 4 4 3 5% 7% 41%	2210
	11th to 20th	Night	15% 9% 3 8% 4 4 4 5% 6% 8% 35%	2210
	21st to end	Night	16% 6% 3 7% 4 4 4 3 5% 7% 42%	2542
August	1st to 10th	Night	9% 7% 3 7% 5% 5% 6% 5% 6% 7% 39%	2790
	11th to 20th	Night	18% 9% 3 6% 4 3 4 3 5% 6% 40%	2785
	21st to end	Night	14% 6% 2 6% 3 3 3 3 4 5% 49%	3124
September	1st to 10th	Night	19% 8% 3 5% 4 4 3 3 5% 7% 40%	1843
	11th to 20th	Night	21% 11% 2 5% 3 3 3 2 4 6% 39%	2090
	21st to end	Night	21% 12% 2 6% 4 3 4 2 4 5% 37%	2090
October	1st to 10th	Night	20% 13% 2 8% 5% 4 3 3 5% 6% 30%	2250
	11th to 20th	Night	26% 19% 5% 7% 4 4 4 3 4 4 21%	2280
	21st to end	Night	22% 22% 5% 8% 4 4 4 3 4 5% 19%	2698
November	1st to 10th	Night	19% 19% 6% 12% 5% 4 4 3 4 5% 18%	2680
	11th to 20th	Night	21% 19% 7% 14% 6% 5% 4 2 3 3 16%	2800
	21st to end	Night	18% 23% 8% 15% 6% 5% 4 3 3 3 11%	2810
December	1st to 10th	Night	10% 26% 10% 20% 10% 7% 3 2 2 2 7%	4910
	11th to 20th	Night	10% 18% 7% 16% 10% 8% 6% 4 4 4 13%	5586
	21st to end	Night	20% 22% 6% 13% 7% 5% 4 3 4 4 12%	7502

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	81% 4 6% 6% 2 2	3159
	11th to 20th	Day	69% 3 8% 14% 6%	3273
	21st to end	Day	74% 3 5% 14% 4	3982
February	1st to 10th	Day	64% 6% 8% 15% 6%	1796
	11th to 20th	Day	64% 5% 9% 14% 9%	1762
	21st to end	Day	66% 5% 5% 15% 8% 1	1570
March	1st to 10th	Day	61% 6% 8% 13% 10% 2	4658
	11th to 20th	Day	67% 4 10% 12% 7%	4980
	21st to end	Day	64% 4 7% 15% 10% 1	5465
April	1st to 10th	Day	63% 5% 7% 16% 8% 1	2414
	11th to 20th	Day	57% 5% 7% 21% 9% 1	2442
	21st to end	Day	54% 5% 9% 16% 14% 2	2470
May	1st to 10th	Day	50% 8% 11% 19% 12% 1	4201
	11th to 20th	Day	47% 9% 13% 19% 11% 1	4457
	21st to end	Day	48% 8% 11% 19% 12% 2	5185
June	1st to 10th	Day	52% 7% 12% 19% 10%	2850
	11th to 20th	Day	46% 7% 11% 22% 14%	2850
	21st to end	Day	53% 7% 11% 19% 10%	2850
July	1st to 10th	Day	50% 6% 14% 23% 6%	4686
	11th to 20th	Day	43% 7% 20% 21% 10% 1	4679
	21st to end	Day	46% 5% 13% 29% 7%	4860
August	1st to 10th	Day	43% 7% 16% 27% 8%	4124
	11th to 20th	Day	46% 6% 15% 27% 5%	4083
	21st to end	Day	44% 5% 14% 28% 6% 2	4531
September	1st to 10th	Day	49% 7% 15% 20% 8%	2316
	11th to 20th	Day	52% 7% 16% 20% 5%	2090
	21st to end	Day	55% 6% 11% 21% 7%	2090
October	1st to 10th	Day	56% 5% 13% 20% 6%	3202
	11th to 20th	Day	61% 3 11% 20% 5%	3140
	21st to end	Day	72% 3 11% 8% 5%	3095
November	1st to 10th	Day	70% 6% 10% 9% 5%	1618
	11th to 20th	Day	79% 4 7% 8% 3	1600
	21st to end	Day	82% 4 7% 6% 1	1587
December	1st to 10th	Day	86% 3 5% 4 2	2280
	11th to 20th	Day	71% 4 12% 11% 2	2621
	21st to end	Day	79% 3 4 13% 3	3476
January	1st to 10th	Night	80% 5% 6% 6% 2 1	6808
	11th to 20th	Night	74% 3 7% 11% 5%	6705
	21st to end	Night	69% 4 6% 15% 6%	6996
February	1st to 10th	Night	63% 5% 11% 13% 7%	2602
	11th to 20th	Night	64% 5% 10% 14% 6%	2535
	21st to end	Night	66% 5% 8% 13% 7% 1	2058
March	1st to 10th	Night	63% 4 8% 13% 9% 3	5194
	11th to 20th	Night	69% 4 6% 13% 7% 1	4980
	21st to end	Night	62% 5% 7% 15% 10% 2	5467
April	1st to 10th	Night	59% 5% 8% 15% 11% 1	2001
	11th to 20th	Night	54% 6% 8% 19% 11% 2	1693
	21st to end	Night	51% 5% 9% 17% 16% 2	1710
May	1st to 10th	Night	48% 7% 8% 21% 14% 2	2758
	11th to 20th	Night	45% 8% 13% 25% 8% 1	2440
	21st to end	Night	43% 8% 13% 19% 15% 2	2403
June	1st to 10th	Night	50% 7% 9% 20% 12% 2	1330
	11th to 20th	Night	45% 5% 11% 21% 16% 1	1330
	21st to end	Night	45% 7% 12% 22% 12% 1	1330
July	1st to 10th	Night	42% 5% 14% 30% 8% 1	2175
	11th to 20th	Night	46% 5% 15% 25% 9%	2168
	21st to end	Night	43% 5% 15% 27% 11%	2461
August	1st to 10th	Night	42% 7% 14% 32% 5%	2781
	11th to 20th	Night	45% 6% 13% 31% 5%	2812
	21st to end	Night	37% 5% 12% 34% 11% 1	3124
September	1st to 10th	Night	45% 6% 16% 24% 9%	1843
	11th to 20th	Night	47% 7% 18% 23% 5%	2090
	21st to end	Night	49% 6% 15% 22% 7%	2090
October	1st to 10th	Night	52% 6% 11% 25% 7%	3757
	11th to 20th	Night	61% 5% 11% 19% 6%	3779
	21st to end	Night	64% 5% 15% 12% 4	4436
November	1st to 10th	Night	69% 5% 11% 12% 3	2680
	11th to 20th	Night	75% 5% 9% 9% 3	2800
	21st to end	Night	80% 5% 7% 6% 1	2810
December	1st to 10th	Night	85% 3 5% 5% 2	4910
	11th to 20th	Night	75% 4 6% 10% 4	5585
	21st to end	Night	76% 3 6% 11% 4	7502

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	23% 17% 37% 16% 7% 2	200
	11th to 20th	Day	19% 18% 33% 24% 4 1	225
	21st to end	Day	25% 13% 35% 22% 5% 1	330
February	1st to 10th	Day	21% 23% 36% 15% 4 1	300
	11th to 20th	Day	20% 20% 41% 15% 2 2	300
	21st to end	Day	26% 29% 34% 11% 1	249
March	1st to 10th	Day	20% 19% 42% 16% 3	374
	11th to 20th	Day	26% 18% 34% 16% 5% 1	500
	21st to end	Day	26% 19% 33% 16% 5% 1	550
April	1st to 10th	Day	24% 19% 32% 17% 6% 1	500
	11th to 20th	Day	30% 18% 27% 15% 7% 2	452
	21st to end	Day	28% 18% 27% 17% 7% 3	460
May	1st to 10th	Day	24% 13% 37% 16% 8% 2	463
	11th to 20th	Day	22% 15% 34% 20% 7% 3	516
	21st to end	Day	24% 15% 33% 20% 7% 1	734
June	1st to 10th	Day	23% 13% 36% 21% 6% 1	680
	11th to 20th	Day	24% 15% 31% 22% 7% 1	680
	21st to end	Day	26% 10% 27% 25% 10% 2	680
July	1st to 10th	Day	20% 11% 32% 28% 7% 3	671
	11th to 20th	Day	18% 13% 28% 29% 11% 2	668
	21st to end	Day	19% 9% 32% 25% 12% 3	739
August	1st to 10th	Day	19% 10% 29% 28% 10% 4	509
	11th to 20th	Day	20% 6% 27% 25% 16% 6%	479
	21st to end	Day	23% 9% 28% 24% 11% 5%	539
September	1st to 10th	Day	24% 11% 30% 22% 11% 3	490
	11th to 20th	Day	28% 10% 31% 22% 8% 2	490
	21st to end	Day	30% 14% 25% 21% 9% 1	490
October	1st to 10th	Day	30% 16% 28% 19% 6% 2	490
	11th to 20th	Day	34% 19% 29% 14% 3 1	490
	21st to end	Day	32% 23% 29% 14% 2	344
November	1st to 10th	Day	39% 15% 31% 13% 2	227
	11th to 20th	Day	34% 25% 29% 11% 2 1	200
	21st to end	Day	38% 23% 27% 10% 3	200
December	1st to 10th	Day	24% 16% 39% 14% 7% 1	200
	11th to 20th	Day	26% 18% 40% 12% 4 2	200
	21st to end	Day	30% 18% 30% 16% 5% 1	220
January	1st to 10th	Night	23% 13% 38% 20% 5% 1	1000
	11th to 20th	Night	22% 14% 31% 24% 8% 1	1000
	21st to end	Night	18% 13% 30% 28% 9% 1	1100
February	1st to 10th	Night	15% 14% 38% 25% 7% 1	802
	11th to 20th	Night	18% 15% 34% 25% 7% 1	783
	21st to end	Night	19% 17% 37% 23% 5%	660
March	1st to 10th	Night	20% 16% 36% 21% 6% 1	800
	11th to 20th	Night	23% 18% 32% 20% 6% 1	800
	21st to end	Night	20% 13% 37% 22% 8% 1	880
April	1st to 10th	Night	27% 16% 29% 22% 5% 1	711
	11th to 20th	Night	25% 16% 25% 25% 8% 1	565
	21st to end	Night	24% 12% 30% 26% 9% 1	570
May	1st to 10th	Night	21% 9% 32% 30% 8%	527
	11th to 20th	Night	22% 10% 32% 29% 5% 2	374
	21st to end	Night	18% 11% 36% 30% 5%	411
June	1st to 10th	Night	28% 7% 26% 32% 7% 1	380
	11th to 20th	Night	18% 8% 32% 31% 10% 1	380
	21st to end	Night	19% 9% 26% 33% 11% 1	380
July	1st to 10th	Night	18% 8% 30% 32% 11% 1	370
	11th to 20th	Night	16% 6% 30% 37% 11%	368
	21st to end	Night	16% 5% 30% 34% 14% 1	494
August	1st to 10th	Night	17% 6% 26% 35% 15% 2	567
	11th to 20th	Night	18% 5% 22% 33% 19% 2	564
	21st to end	Night	20% 7% 28% 26% 17% 2	627
September	1st to 10th	Night	24% 7% 27% 26% 14% 2	689
	11th to 20th	Night	28% 7% 28% 24% 12% 1	760
	21st to end	Night	28% 8% 26% 25% 10% 2	760
October	1st to 10th	Night	29% 11% 28% 25% 8%	760
	11th to 20th	Night	35% 13% 28% 18% 5% 1	760
	21st to end	Night	36% 13% 27% 20% 5% 1	836
November	1st to 10th	Night	31% 15% 30% 19% 4 1	780
	11th to 20th	Night	33% 16% 28% 19% 5%	800
	21st to end	Night	31% 15% 35% 15% 4	810
December	1st to 10th	Night	25% 16% 32% 21% 7%	1000
	11th to 20th	Night	25% 14% 34% 20% 6% 1	1000
	21st to end	Night	29% 13% 30% 19% 7% 2	1100

Page generated at 2025-04-08 09:17:28. Version ac07

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