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 2024-10-25.

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	16% 13% 4 9% 5% 5% 5% 3 5% 6% 28%	101664
	Night	15% 15% 5% 11% 6% 5% 5% 3 5% 5% 25%	97246
Transparency	Day	56% 6% 11% 18% 8% 1	101402
	Night	60% 6% 10% 17% 7% 1	97127
Seeing	Day	24% 15% 31% 20% 7% 2	15378
	Night	24% 12% 31% 24% 8% 1	24440

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	11% 23% 9% 14% 6% 9% 6% 4 5% 4 9%	2208
	11th to 20th	Day	7% 13% 7% 19% 8% 6% 6% 5% 5% 4 19%	2281
	21st to end	Day	9% 23% 10% 15% 7% 6% 5% 3 5% 4 11%	2783
February	1st to 10th	Day	8% 14% 6% 13% 8% 8% 9% 4 6% 7% 19%	1706
	11th to 20th	Day	9% 20% 5% 10% 6% 7% 6% 5% 6% 7% 18%	1663
	21st to end	Day	9% 18% 6% 12% 8% 7% 6% 4 4 5% 20%	1494
March	1st to 10th	Day	11% 16% 4 10% 7% 6% 6% 5% 5% 6% 25%	3239
	11th to 20th	Day	9% 20% 8% 14% 8% 4 4 3 4 4 24%	3480
	21st to end	Day	13% 17% 5% 12% 6% 6% 5% 3 4 5% 25%	3815
April	1st to 10th	Day	19% 17% 6% 11% 5% 3 3 3 4 6% 23%	2293
	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% 24% 7% 10% 5% 3 3 3 3 4 14%	1838
November	1st to 10th	Day	21% 21% 6% 11% 4 5% 3 2 4 4 18%	1536
	11th to 20th	Day	19% 24% 7% 14% 7% 5% 3 3 3 3 12%	1520
	21st to end	Day	20% 23% 6% 16% 7% 5% 4 3 4 3 9%	1508
December	1st to 10th	Day	15% 20% 7% 18% 9% 3 5% 4 4 5% 11%	1330
	11th to 20th	Day	14% 16% 6% 16% 7% 6% 5% 3 4 4 18%	1671
	21st to end	Day	17% 21% 10% 21% 9% 3 3 2 3 3 8%	2431
January	1st to 10th	Night	11% 19% 8% 15% 9% 10% 6% 4 5% 4 10%	4748
	11th to 20th	Night	9% 15% 7% 16% 10% 8% 7% 5% 5% 5% 14%	4687
	21st to end	Night	10% 21% 10% 14% 8% 7% 5% 4 5% 4 13%	4884
February	1st to 10th	Night	8% 14% 5% 11% 11% 7% 7% 4 6% 7% 20%	2472
	11th to 20th	Night	10% 16% 5% 14% 7% 6% 5% 4 6% 6% 20%	2403
	21st to end	Night	11% 17% 6% 14% 7% 7% 6% 4 5% 5% 18%	1959
March	1st to 10th	Night	16% 16% 4 10% 4 4 4 3 4 5% 29%	3600
	11th to 20th	Night	12% 19% 6% 15% 7% 4 3 2 3 4 25%	3479
	21st to end	Night	13% 13% 6% 12% 6% 6% 5% 3 4 5% 26%	3817
April	1st to 10th	Night	19% 16% 4 9% 5% 4 4 3 5% 5% 26%	1902
	11th to 20th	Night	19% 12% 4 10% 4 5% 3 3 5% 5% 30%	1687
	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% 5% 4 4 3 4 5% 19%	2619
November	1st to 10th	Night	18% 19% 6% 13% 5% 4 4 3 4 4 19%	2542
	11th to 20th	Night	21% 18% 7% 14% 6% 5% 4 2 3 3 16%	2660
	21st to end	Night	18% 22% 8% 15% 7% 6% 4 3 3 3 11%	2669
December	1st to 10th	Night	13% 22% 6% 17% 9% 8% 4 3 3 4 11%	2850
	11th to 20th	Night	14% 19% 7% 14% 9% 7% 5% 4 4 4 13%	3526
	21st to end	Night	20% 21% 6% 17% 8% 5% 4 2 3 3 10%	5236

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	77% 5% 8% 8% 2	2209
	11th to 20th	Day	67% 4 9% 15% 4	2281
	21st to end	Day	75% 4 6% 10% 4	2783
February	1st to 10th	Day	64% 6% 8% 15% 7%	1706
	11th to 20th	Day	63% 5% 9% 14% 8%	1672
	21st to end	Day	66% 5% 5% 14% 9% 1	1494
March	1st to 10th	Day	58% 7% 11% 17% 6% 1	3242
	11th to 20th	Day	65% 5% 9% 15% 6% 1	3480
	21st to end	Day	61% 6% 7% 15% 11% 1	3815
April	1st to 10th	Day	63% 5% 7% 15% 8% 1	2293
	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	58% 5% 13% 19% 5%	1929
	11th to 20th	Day	70% 5% 8% 14% 3	1900
	21st to end	Day	76% 5% 8% 8% 3	1838
November	1st to 10th	Day	71% 6% 10% 9% 5%	1536
	11th to 20th	Day	78% 4 7% 7% 3	1520
	21st to end	Day	81% 5% 7% 6% 1	1508
December	1st to 10th	Day	77% 5% 8% 7% 4	1330
	11th to 20th	Day	69% 5% 9% 13% 3	1671
	21st to end	Day	84% 3 4 7% 2	2431
January	1st to 10th	Night	77% 6% 8% 7% 1	4748
	11th to 20th	Night	71% 5% 9% 13% 2	4687
	21st to end	Night	74% 5% 7% 10% 3	4884
February	1st to 10th	Night	62% 5% 12% 13% 7%	2472
	11th to 20th	Night	63% 5% 10% 15% 6%	2405
	21st to end	Night	66% 5% 8% 12% 7% 1	1959
March	1st to 10th	Night	58% 5% 11% 17% 9% 1	3610
	11th to 20th	Night	63% 5% 7% 16% 8% 1	3480
	21st to end	Night	58% 6% 8% 12% 13% 2	3817
April	1st to 10th	Night	59% 5% 8% 15% 11% 1	1902
	11th to 20th	Night	55% 6% 8% 19% 11% 2	1687
	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	54% 6% 14% 20% 6%	2250
	11th to 20th	Night	67% 5% 9% 14% 3	2280
	21st to end	Night	69% 5% 10% 12% 5%	2619
November	1st to 10th	Night	68% 5% 11% 12% 3	2542
	11th to 20th	Night	74% 5% 9% 9% 3	2660
	21st to end	Night	79% 5% 8% 6% 2	2669
December	1st to 10th	Night	78% 5% 7% 7% 3	2850
	11th to 20th	Night	74% 6% 7% 10% 3	3525
	21st to end	Night	81% 4 7% 6% 3	5236

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	24% 18% 35% 14% 7% 2	180
	11th to 20th	Day	18% 19% 34% 23% 5% 1	202
	21st to end	Day	26% 11% 35% 23% 5% 1	297
February	1st to 10th	Day	20% 24% 35% 16% 4 1	270
	11th to 20th	Day	20% 19% 41% 16% 3 2	270
	21st to end	Day	24% 30% 35% 9% 1	225
March	1st to 10th	Day	20% 19% 41% 17% 3	340
	11th to 20th	Day	25% 18% 34% 17% 5% 1	460
	21st to end	Day	25% 17% 34% 17% 5% 1	506
April	1st to 10th	Day	24% 18% 33% 18% 6% 1	460
	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	31% 22% 30% 14% 2	325
November	1st to 10th	Day	40% 16% 30% 12% 2	205
	11th to 20th	Day	32% 27% 28% 11% 2 1	180
	21st to end	Day	35% 25% 27% 10% 3	180
December	1st to 10th	Day	24% 17% 37% 14% 7% 1	180
	11th to 20th	Day	26% 19% 38% 12% 4 2	180
	21st to end	Day	29% 20% 29% 15% 6% 1	198
January	1st to 10th	Night	23% 14% 36% 20% 5% 1	950
	11th to 20th	Night	22% 14% 31% 24% 8% 1	950
	21st to end	Night	19% 12% 29% 28% 10% 1	1045
February	1st to 10th	Night	15% 14% 38% 25% 8% 1	762
	11th to 20th	Night	18% 15% 33% 25% 8% 1	743
	21st to end	Night	19% 17% 37% 22% 5%	628
March	1st to 10th	Night	20% 15% 36% 22% 6% 1	760
	11th to 20th	Night	23% 18% 32% 21% 6% 1	760
	21st to end	Night	20% 13% 37% 22% 8% 1	836
April	1st to 10th	Night	27% 15% 30% 22% 6% 1	676
	11th to 20th	Night	25% 16% 25% 25% 8% 1	563
	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% 12% 26% 20% 5% 1	812
November	1st to 10th	Night	30% 15% 31% 19% 4 1	740
	11th to 20th	Night	33% 16% 28% 18% 5%	760
	21st to end	Night	30% 15% 35% 15% 5%	769
December	1st to 10th	Night	25% 16% 32% 21% 7%	950
	11th to 20th	Night	26% 15% 33% 19% 6% 1	950
	21st to end	Night	29% 13% 30% 20% 7% 2	1045

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