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 2024-03-01.

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	17% 13% 5% 9% 7% 4 5% 4 5% 6% 25%	77947
	Night	16% 14% 6% 10% 8% 4 5% 4 5% 5% 23%	81496
Transparency	Day	59% 6% 10% 17% 7% 1	77635
	Night	62% 6% 10% 15% 6% 1	81343
Seeing	Day	25% 15% 31% 20% 7% 2	14359
	Night	24% 12% 30% 24% 8% 1	23718

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% 22% 10% 13% 8% 6% 7% 5% 5% 4 9%	2208
	11th to 20th	Day	8% 12% 8% 16% 11% 5% 7% 6% 5% 4 19%	2281
	21st to end	Day	10% 22% 11% 14% 8% 4 6% 5% 5% 4 12%	2783
February	1st to 10th	Day	8% 13% 7% 11% 9% 5% 10% 6% 6% 7% 19%	1706
	11th to 20th	Day	9% 18% 6% 9% 8% 5% 7% 6% 6% 7% 19%	1663
	21st to end	Day	10% 17% 7% 10% 9% 6% 6% 5% 5% 5% 21%	1494
March	1st to 10th	Day	11% 15% 4 10% 9% 6% 6% 6% 4 6% 24%	1863
	11th to 20th	Day	12% 15% 6% 9% 7% 4 4 4 5% 4 29%	1980
	21st to end	Day	15% 16% 5% 9% 6% 3 4 3 4 5% 31%	2178
April	1st to 10th	Day	20% 16% 7% 10% 6% 2 4 4 4 6% 22%	2171
	11th to 20th	Day	19% 13% 4 7% 6% 3 4 3 5% 6% 29%	2312
	21st to end	Day	19% 11% 5% 7% 5% 3 4 4 4 5% 33%	2340
May	1st to 10th	Day	17% 12% 4 8% 6% 5% 5% 5% 6% 7% 26%	2379
	11th to 20th	Day	20% 9% 4 6% 6% 3 5% 4 6% 7% 31%	2505
	21st to end	Day	18% 9% 3 5% 5% 3 5% 5% 5% 8% 34%	2919
June	1st to 10th	Day	21% 8% 4 6% 5% 3 5% 5% 6% 7% 30%	2700
	11th to 20th	Day	18% 7% 3 6% 6% 3 4 4 5% 8% 37%	2700
	21st to end	Day	20% 9% 3 6% 6% 4 5% 5% 5% 7% 30%	2700
July	1st to 10th	Day	18% 6% 3 5% 6% 4 5% 5% 6% 8% 34%	2700
	11th to 20th	Day	16% 7% 3 6% 6% 3 5% 6% 7% 9% 33%	2700
	21st to end	Day	18% 7% 2 6% 7% 4 6% 5% 6% 8% 32%	2864
August	1st to 10th	Day	18% 8% 3 6% 7% 4 5% 5% 7% 9% 29%	2349
	11th to 20th	Day	17% 7% 3 6% 5% 4 5% 5% 6% 6% 35%	2303
	21st to end	Day	19% 7% 3 7% 5% 4 5% 5% 6% 9% 31%	2574
September	1st to 10th	Day	21% 6% 3 7% 5% 4 4 5% 5% 8% 33%	2195
	11th to 20th	Day	24% 11% 3 6% 5% 3 4 4 4 6% 31%	1980
	21st to end	Day	24% 11% 4 6% 6% 2 4 3 4 6% 31%	1980
October	1st to 10th	Day	24% 14% 4 6% 4 3 4 3 4 5% 28%	1828
	11th to 20th	Day	26% 21% 5% 6% 5% 4 3 3 3 4 18%	1800
	21st to end	Day	25% 24% 7% 9% 7% 3 3 3 3 4 13%	1796
November	1st to 10th	Day	21% 20% 7% 10% 5% 4 4 3 4 4 18%	1536
	11th to 20th	Day	20% 22% 8% 12% 9% 4 4 4 3 3 12%	1520
	21st to end	Day	20% 22% 7% 15% 8% 5% 4 4 3 3 10%	1508
December	1st to 10th	Day	16% 18% 8% 16% 11% 2 5% 5% 4 5% 11%	1330
	11th to 20th	Day	14% 16% 7% 14% 9% 4 6% 5% 4 4 19%	1671
	21st to end	Day	18% 21% 10% 17% 12% 2 3 3 3 3 8%	2431
January	1st to 10th	Night	11% 18% 8% 13% 10% 7% 8% 5% 4 4 10%	4748
	11th to 20th	Night	9% 14% 7% 14% 12% 6% 7% 6% 5% 5% 15%	4687
	21st to end	Night	10% 21% 10% 13% 9% 5% 6% 5% 4 4 14%	4884
February	1st to 10th	Night	9% 12% 6% 10% 12% 5% 8% 5% 6% 7% 20%	2472
	11th to 20th	Night	10% 15% 6% 12% 9% 5% 6% 5% 5% 6% 21%	2403
	21st to end	Night	11% 15% 7% 12% 9% 5% 7% 5% 6% 5% 19%	1959
March	1st to 10th	Night	10% 12% 6% 13% 8% 4 6% 5% 5% 5% 26%	2090
	11th to 20th	Night	15% 13% 6% 11% 8% 4 4 3 3 6% 26%	1979
	21st to end	Night	13% 13% 5% 8% 6% 4 5% 4 4 6% 33%	2178
April	1st to 10th	Night	21% 14% 5% 8% 6% 3 4 4 5% 5% 25%	1803
	11th to 20th	Night	19% 11% 4 9% 5% 3 4 4 5% 6% 30%	1597
	21st to end	Night	19% 10% 5% 6% 4 2 4 4 5% 6% 35%	1620
May	1st to 10th	Night	17% 8% 3 7% 7% 3 5% 5% 7% 7% 32%	1580
	11th to 20th	Night	17% 9% 4 7% 5% 3 5% 5% 6% 5% 33%	1385
	21st to end	Night	16% 7% 2 7% 5% 3 4 4 6% 6% 40%	1357
June	1st to 10th	Night	22% 8% 3 5% 5% 3 4 4 4 7% 34%	1260
	11th to 20th	Night	16% 7% 2 7% 6% 3 4 4 6% 8% 38%	1260
	21st to end	Night	19% 7% 3 5% 4 2 4 5% 6% 9% 36%	1260
July	1st to 10th	Night	17% 5% 3 4 5% 3 4 5% 5% 8% 40%	1260
	11th to 20th	Night	14% 6% 2 5% 4 3 6% 5% 6% 10% 39%	1260
	21st to end	Night	15% 6% 2 6% 4 3 4 4 5% 8% 41%	1451
August	1st to 10th	Night	12% 7% 3 5% 6% 4 5% 7% 6% 8% 36%	1588
	11th to 20th	Night	16% 6% 3 6% 4 3 5% 5% 5% 7% 41%	1598
	21st to end	Night	18% 7% 3 6% 5% 2 4 6% 5% 6% 39%	1782
September	1st to 10th	Night	19% 7% 3 4 4 3 3 3 5% 7% 40%	1745
	11th to 20th	Night	23% 11% 3 5% 4 2 3 3 4 6% 37%	1980
	21st to end	Night	22% 11% 3 5% 5% 2 4 3 4 5% 36%	1980
October	1st to 10th	Night	21% 12% 2 7% 6% 3 4 4 5% 6% 30%	2131
	11th to 20th	Night	27% 17% 5% 6% 5% 3 5% 4 4 4 20%	2160
	21st to end	Night	23% 22% 6% 7% 6% 3 4 3 3 5% 19%	2556
November	1st to 10th	Night	18% 18% 7% 11% 6% 3 5% 4 4 5% 19%	2542
	11th to 20th	Night	21% 16% 8% 13% 8% 4 5% 3 3 4 16%	2660
	21st to end	Night	18% 20% 9% 14% 8% 4 5% 4 4 3 11%	2669
December	1st to 10th	Night	13% 21% 7% 15% 11% 6% 6% 4 3 4 11%	2850
	11th to 20th	Night	15% 18% 7% 12% 10% 5% 6% 5% 4 4 13%	3526
	21st to end	Night	20% 20% 7% 14% 11% 4 5% 3 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	65% 5% 5% 14% 9% 2	1494
March	1st to 10th	Day	61% 5% 9% 14% 9% 1	1866
	11th to 20th	Day	58% 5% 9% 18% 10% 1	1980
	21st to end	Day	56% 4 7% 17% 13% 2	2178
April	1st to 10th	Day	65% 5% 7% 14% 9% 1	2171
	11th to 20th	Day	56% 5% 7% 22% 9% 1	2312
	21st to end	Day	54% 5% 10% 15% 14% 3	2340
May	1st to 10th	Day	56% 7% 10% 15% 11% 2	2379
	11th to 20th	Day	51% 6% 9% 21% 12% 1	2509
	21st to end	Day	49% 7% 12% 22% 9% 2	2919
June	1st to 10th	Day	52% 6% 12% 19% 11%	2700
	11th to 20th	Day	46% 7% 11% 22% 14% 1	2700
	21st to end	Day	52% 7% 12% 19% 10%	2700
July	1st to 10th	Day	46% 8% 14% 24% 8%	2626
	11th to 20th	Day	45% 9% 16% 22% 8%	2619
	21st to end	Day	50% 8% 15% 23% 4	2705
August	1st to 10th	Day	50% 9% 16% 20% 4	2334
	11th to 20th	Day	48% 8% 15% 22% 7%	2303
	21st to end	Day	49% 7% 15% 21% 7%	2574
September	1st to 10th	Day	49% 8% 15% 20% 8% 1	2195
	11th to 20th	Day	55% 7% 15% 19% 4	1980
	21st to end	Day	56% 6% 11% 21% 6%	1980
October	1st to 10th	Day	59% 6% 13% 18% 5%	1828
	11th to 20th	Day	71% 5% 7% 14% 3	1800
	21st to end	Day	76% 5% 7% 8% 4	1796
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	60% 4 10% 14% 11% 2	2100
	11th to 20th	Night	62% 4 8% 16% 9% 1	1980
	21st to end	Night	53% 5% 9% 16% 14% 3	2178
April	1st to 10th	Night	60% 5% 8% 14% 11% 1	1803
	11th to 20th	Night	55% 6% 7% 19% 12% 2	1597
	21st to end	Night	51% 5% 9% 16% 17% 2	1620
May	1st to 10th	Night	49% 6% 11% 21% 11% 2	1580
	11th to 20th	Night	50% 6% 10% 20% 13% 2	1386
	21st to end	Night	44% 6% 15% 20% 13% 1	1358
June	1st to 10th	Night	49% 7% 9% 20% 13% 2	1260
	11th to 20th	Night	45% 6% 10% 21% 17% 2	1260
	21st to end	Night	44% 8% 12% 22% 13% 1	1260
July	1st to 10th	Night	40% 8% 16% 25% 10% 1	1225
	11th to 20th	Night	38% 7% 17% 29% 9%	1218
	21st to end	Night	42% 7% 18% 28% 4	1370
August	1st to 10th	Night	44% 9% 18% 24% 5%	1579
	11th to 20th	Night	41% 8% 17% 26% 7%	1598
	21st to end	Night	44% 7% 16% 24% 8% 1	1782
September	1st to 10th	Night	45% 6% 16% 24% 9%	1745
	11th to 20th	Night	49% 7% 18% 22% 5%	1980
	21st to end	Night	50% 6% 15% 23% 6%	1980
October	1st to 10th	Night	54% 7% 14% 19% 6%	2131
	11th to 20th	Night	68% 6% 9% 14% 3	2160
	21st to end	Night	69% 5% 9% 12% 5%	2556
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% 31% 35% 9% 1	225
March	1st to 10th	Day	20% 19% 40% 17% 3	306
	11th to 20th	Day	26% 18% 33% 16% 6% 1	420
	21st to end	Day	26% 17% 33% 17% 6% 1	462
April	1st to 10th	Day	24% 18% 32% 19% 6%	420
	11th to 20th	Day	28% 18% 28% 16% 8% 2	412
	21st to end	Day	27% 17% 28% 18% 7% 3	420
May	1st to 10th	Day	24% 13% 37% 15% 8% 2	423
	11th to 20th	Day	23% 15% 33% 20% 8% 3	474
	21st to end	Day	23% 15% 34% 20% 7% 1	679
June	1st to 10th	Day	24% 12% 35% 21% 7% 1	630
	11th to 20th	Day	24% 14% 30% 23% 8% 1	630
	21st to end	Day	25% 10% 26% 25% 11% 2	630
July	1st to 10th	Day	19% 11% 32% 28% 7% 3	621
	11th to 20th	Day	18% 13% 27% 29% 12% 2	618
	21st to end	Day	19% 9% 32% 25% 13% 3	684
August	1st to 10th	Day	20% 9% 28% 28% 11% 4	468
	11th to 20th	Day	19% 6% 28% 25% 15% 6%	439
	21st to end	Day	23% 9% 29% 23% 11% 5%	495
September	1st to 10th	Day	23% 11% 30% 22% 12% 3	450
	11th to 20th	Day	30% 11% 31% 20% 6% 2	450
	21st to end	Day	31% 15% 25% 20% 8% 2	450
October	1st to 10th	Day	30% 15% 27% 20% 6% 2	450
	11th to 20th	Day	35% 18% 29% 14% 3 1	450
	21st to end	Day	32% 23% 29% 14% 2	311
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% 21% 5%	628
March	1st to 10th	Night	19% 15% 36% 22% 7% 1	723
	11th to 20th	Night	23% 17% 32% 21% 6% 1	720
	21st to end	Night	19% 14% 36% 22% 8% 1	792
April	1st to 10th	Night	27% 15% 29% 22% 6% 1	641
	11th to 20th	Night	25% 16% 24% 26% 8% 1	533
	21st to end	Night	24% 11% 30% 26% 9% 1	540
May	1st to 10th	Night	21% 8% 32% 31% 8%	500
	11th to 20th	Night	23% 9% 31% 29% 6% 2	354
	21st to end	Night	17% 11% 35% 30% 6% 1	389
June	1st to 10th	Night	28% 7% 26% 32% 7% 1	360
	11th to 20th	Night	18% 8% 32% 31% 11% 1	360
	21st to end	Night	19% 9% 26% 34% 11% 1	360
July	1st to 10th	Night	17% 8% 31% 31% 11% 1	350
	11th to 20th	Night	17% 6% 29% 36% 12%	348
	21st to end	Night	16% 5% 30% 34% 14% 1	467
August	1st to 10th	Night	17% 6% 25% 35% 15% 2	537
	11th to 20th	Night	18% 6% 21% 35% 18% 2	534
	21st to end	Night	21% 7% 29% 24% 17% 2	594
September	1st to 10th	Night	23% 7% 26% 27% 15% 2	652
	11th to 20th	Night	30% 7% 28% 22% 11% 1	720
	21st to end	Night	29% 8% 27% 24% 10% 2	720
October	1st to 10th	Night	29% 11% 27% 25% 8%	720
	11th to 20th	Night	36% 13% 27% 17% 6% 1	720
	21st to end	Night	36% 12% 26% 20% 5% 1	792
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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