Lake Superior Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lake Superior Provincial Park clear sky chart from 2005-11-06 to 2024-11-02.

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% 12% 4 8% 5% 4 4 3 5% 7% 32%	101578
	Night	15% 14% 5% 10% 5% 4 4 3 5% 6% 28%	97474
Transparency	Day	51% 7% 13% 19% 8% 1	101325
	Night	57% 7% 11% 17% 7% 1	97347
Seeing	Day	21% 11% 29% 26% 11% 2	15600
	Night	22% 11% 29% 27% 11% 1	24934

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	10% 24% 13% 16% 7% 5% 5% 3 4 4 9%	2338
	11th to 20th	Day	9% 14% 6% 18% 7% 6% 5% 4 6% 6% 19%	2530
	21st to end	Day	7% 19% 13% 17% 7% 6% 5% 4 5% 5% 12%	2783
February	1st to 10th	Day	7% 16% 5% 13% 11% 9% 6% 4 5% 6% 18%	1587
	11th to 20th	Day	10% 16% 6% 11% 10% 5% 5% 3 4 5% 23%	1746
	21st to end	Day	8% 17% 8% 16% 7% 6% 4 3 6% 7% 21%	1570
March	1st to 10th	Day	11% 12% 4 10% 4 4 4 4 5% 7% 34%	3118
	11th to 20th	Day	10% 19% 4 8% 6% 4 4 3 4 6% 30%	3433
	21st to end	Day	15% 15% 9% 13% 5% 3 4 2 3 5% 25%	3904
April	1st to 10th	Day	16% 15% 5% 8% 5% 3 4 4 5% 7% 29%	2280
	11th to 20th	Day	19% 12% 4 7% 4 4 3 3 5% 6% 32%	2422
	21st to end	Day	16% 12% 3 6% 5% 4 4 4 6% 7% 32%	2470
May	1st to 10th	Day	17% 9% 3 7% 4 4 4 4 5% 6% 37%	4108
	11th to 20th	Day	16% 7% 2 6% 4 4 4 3 6% 7% 41%	4355
	21st to end	Day	19% 7% 2 5% 4 4 4 3 5% 7% 40%	5185
June	1st to 10th	Day	18% 7% 2 6% 5% 5% 6% 4 6% 8% 33%	2850
	11th to 20th	Day	16% 7% 3 6% 4 5% 4 4 6% 9% 35%	2850
	21st to end	Day	18% 7% 2 6% 4 4 5% 4 5% 8% 37%	2850
July	1st to 10th	Day	21% 8% 2 6% 4 4 4 3 5% 6% 37%	4760
	11th to 20th	Day	13% 8% 2 5% 4 3 4 3 6% 8% 44%	4521
	21st to end	Day	15% 6% 2 6% 3 4 4 3 5% 8% 44%	4814
August	1st to 10th	Day	12% 6% 2 6% 4 4 4 5% 7% 10% 41%	4313
	11th to 20th	Day	15% 6% 3 5% 3 4 4 3 5% 8% 44%	4044
	21st to end	Day	20% 7% 2 6% 3 3 3 3 4 5% 43%	4514
September	1st to 10th	Day	21% 7% 2 6% 4 3 3 3 5% 7% 38%	2241
	11th to 20th	Day	22% 6% 2 4 4 4 4 4 6% 7% 38%	2090
	21st to end	Day	24% 7% 3 7% 4 3 4 2 5% 7% 34%	2090
October	1st to 10th	Day	22% 11% 3 7% 3 4 3 3 6% 5% 31%	2047
	11th to 20th	Day	25% 18% 4 9% 6% 5% 3 3 5% 6% 18%	1787
	21st to end	Day	25% 19% 4 8% 6% 4 4 4 4 5% 19%	1881
November	1st to 10th	Day	21% 22% 4 8% 4 3 4 4 5% 5% 19%	1681
	11th to 20th	Day	17% 19% 7% 11% 5% 5% 5% 4 4 6% 17%	1584
	21st to end	Day	18% 27% 6% 10% 6% 4 5% 4 4 5% 11%	1400
December	1st to 10th	Day	11% 26% 9% 16% 7% 5% 2 2 3 3 14%	1330
	11th to 20th	Day	14% 20% 7% 16% 6% 5% 4 4 5% 5% 14%	1671
	21st to end	Day	20% 23% 7% 13% 4 4 4 3 5% 4 14%	2431
January	1st to 10th	Night	11% 21% 10% 17% 5% 4 4 3 4 5% 15%	4616
	11th to 20th	Night	8% 16% 9% 18% 10% 5% 5% 4 4 4 17%	4440
	21st to end	Night	10% 18% 13% 18% 8% 6% 5% 3 4 4 12%	4884
February	1st to 10th	Night	8% 18% 7% 15% 13% 6% 5% 4 5% 5% 15%	2591
	11th to 20th	Night	10% 14% 7% 16% 8% 5% 5% 4 6% 5% 20%	2318
	21st to end	Night	9% 18% 7% 13% 7% 7% 5% 3 5% 5% 21%	1884
March	1st to 10th	Night	14% 13% 4 9% 4 3 4 3 6% 9% 31%	3722
	11th to 20th	Night	10% 16% 6% 10% 4 4 3 3 5% 6% 33%	3525
	21st to end	Night	14% 12% 8% 13% 5% 4 4 2 4 6% 28%	3755
April	1st to 10th	Night	18% 13% 4 7% 5% 5% 4 4 5% 6% 30%	1900
	11th to 20th	Night	18% 12% 4 8% 5% 4 4 3 4 5% 33%	1706
	21st to end	Night	17% 11% 3 6% 5% 3 4 3 5% 6% 37%	1710
May	1st to 10th	Night	19% 9% 4 6% 4 3 3 2 4 5% 40%	2833
	11th to 20th	Night	15% 8% 2 7% 4 4 4 3 6% 7% 39%	2531
	21st to end	Night	17% 9% 3 6% 4 4 4 3 4 5% 39%	2402
June	1st to 10th	Night	17% 7% 2 6% 5% 4 5% 3 5% 8% 38%	1330
	11th to 20th	Night	18% 10% 3 7% 3 3 3 3 5% 7% 36%	1330
	21st to end	Night	15% 7% 2 7% 5% 5% 4 4 6% 7% 39%	1330
July	1st to 10th	Night	17% 8% 3 8% 5% 3 4 4 5% 8% 36%	2210
	11th to 20th	Night	12% 6% 2 7% 4 4 4 4 5% 8% 44%	2432
	21st to end	Night	16% 7% 3 7% 4 4 3 3 5% 7% 42%	2750
August	1st to 10th	Night	14% 9% 3 7% 5% 5% 5% 4 5% 7% 35%	2609
	11th to 20th	Night	14% 5% 2 6% 4 4 4 3 5% 8% 47%	2785
	21st to end	Night	16% 7% 2 5% 4 3 3 2 5% 5% 48%	3140
September	1st to 10th	Night	16% 8% 3 6% 4 3 4 3 5% 7% 43%	1919
	11th to 20th	Night	20% 6% 2 5% 4 4 3 3 5% 8% 39%	2090
	21st to end	Night	24% 8% 2 5% 3 3 3 3 4 7% 36%	2090
October	1st to 10th	Night	24% 10% 3 6% 4 4 4 3 5% 5% 33%	2133
	11th to 20th	Night	26% 15% 3 7% 5% 4 3 3 4 6% 24%	2389
	21st to end	Night	25% 19% 3 8% 4 4 4 3 4 5% 20%	2717
November	1st to 10th	Night	21% 20% 5% 8% 4 4 4 3 4 5% 21%	2420
	11th to 20th	Night	21% 21% 6% 11% 5% 4 4 3 5% 5% 15%	2593
	21st to end	Night	18% 23% 7% 11% 5% 4 5% 3 5% 5% 14%	2778
December	1st to 10th	Night	12% 25% 8% 15% 6% 4 4 3 4 5% 14%	2850
	11th to 20th	Night	13% 23% 8% 13% 6% 4 4 3 4 5% 17%	3526
	21st to end	Night	15% 23% 7% 13% 6% 4 5% 3 5% 6% 13%	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	78% 7% 8% 6% 1	2339
	11th to 20th	Day	65% 8% 12% 12% 2	2530
	21st to end	Day	72% 10% 9% 5% 4	2783
February	1st to 10th	Day	66% 8% 11% 10% 5%	1587
	11th to 20th	Day	62% 8% 12% 11% 7% 1	1755
	21st to end	Day	62% 5% 10% 12% 8% 1	1570
March	1st to 10th	Day	47% 7% 18% 15% 12% 2	3120
	11th to 20th	Day	54% 6% 13% 18% 8% 1	3433
	21st to end	Day	62% 5% 10% 10% 10% 2	3904
April	1st to 10th	Day	54% 6% 12% 18% 9% 1	2280
	11th to 20th	Day	52% 4 11% 21% 11% 1	2422
	21st to end	Day	47% 6% 10% 19% 14% 4	2470
May	1st to 10th	Day	44% 7% 10% 26% 12% 2	4120
	11th to 20th	Day	41% 8% 13% 24% 13% 1	4359
	21st to end	Day	42% 7% 13% 21% 16% 2	5185
June	1st to 10th	Day	46% 8% 13% 20% 11% 2	2850
	11th to 20th	Day	43% 8% 14% 22% 12% 1	2850
	21st to end	Day	44% 8% 14% 22% 10% 1	2850
July	1st to 10th	Day	47% 7% 15% 22% 9% 1	4686
	11th to 20th	Day	38% 6% 21% 25% 9% 1	4443
	21st to end	Day	37% 7% 14% 32% 10%	4662
August	1st to 10th	Day	35% 8% 20% 29% 7%	4298
	11th to 20th	Day	38% 5% 17% 31% 9%	4083
	21st to end	Day	43% 6% 15% 25% 11% 1	4513
September	1st to 10th	Day	46% 6% 16% 23% 10%	2241
	11th to 20th	Day	44% 7% 20% 24% 5%	2090
	21st to end	Day	50% 6% 17% 20% 6% 1	2090
October	1st to 10th	Day	54% 6% 15% 19% 5% 1	2047
	11th to 20th	Day	67% 7% 11% 12% 2	1787
	21st to end	Day	68% 6% 10% 11% 5%	1881
November	1st to 10th	Day	66% 6% 11% 13% 3	1681
	11th to 20th	Day	67% 9% 11% 8% 4	1584
	21st to end	Day	76% 9% 7% 6% 2	1400
December	1st to 10th	Day	76% 6% 7% 8% 2	1330
	11th to 20th	Day	72% 8% 10% 8% 2	1671
	21st to end	Day	73% 7% 9% 6% 5%	2431
January	1st to 10th	Night	72% 9% 8% 7% 4	4616
	11th to 20th	Night	70% 9% 11% 9% 2	4440
	21st to end	Night	76% 10% 5% 6% 3	4884
February	1st to 10th	Night	70% 8% 9% 9% 4	2591
	11th to 20th	Night	63% 9% 13% 11% 4	2320
	21st to end	Night	63% 7% 11% 12% 7%	1884
March	1st to 10th	Night	48% 7% 15% 18% 11%	3733
	11th to 20th	Night	49% 5% 16% 21% 8% 1	3526
	21st to end	Night	56% 8% 12% 13% 9% 2	3755
April	1st to 10th	Night	54% 6% 11% 18% 11% 1	1900
	11th to 20th	Night	52% 4 9% 21% 11% 2	1706
	21st to end	Night	48% 4 12% 18% 15% 3	1710
May	1st to 10th	Night	46% 5% 8% 24% 15% 2	2840
	11th to 20th	Night	43% 7% 12% 29% 9% 1	2532
	21st to end	Night	46% 7% 11% 18% 14% 5%	2403
June	1st to 10th	Night	43% 7% 12% 20% 16% 2	1330
	11th to 20th	Night	45% 8% 11% 20% 14% 2	1330
	21st to end	Night	43% 9% 14% 24% 10% 1	1330
July	1st to 10th	Night	45% 6% 14% 26% 8%	2175
	11th to 20th	Night	37% 6% 17% 29% 10% 1	2388
	21st to end	Night	41% 6% 11% 25% 17% 1	2662
August	1st to 10th	Night	45% 7% 13% 26% 8%	2600
	11th to 20th	Night	36% 6% 18% 30% 10%	2812
	21st to end	Night	38% 5% 11% 31% 14%	3140
September	1st to 10th	Night	41% 7% 14% 27% 10% 1	1919
	11th to 20th	Night	43% 9% 17% 24% 7%	2090
	21st to end	Night	47% 7% 17% 22% 7%	2090
October	1st to 10th	Night	52% 7% 13% 21% 5% 1	2133
	11th to 20th	Night	62% 7% 12% 15% 3	2389
	21st to end	Night	67% 7% 10% 11% 4	2717
November	1st to 10th	Night	66% 6% 10% 14% 4	2420
	11th to 20th	Night	71% 9% 9% 9% 3	2593
	21st to end	Night	71% 10% 12% 5% 1	2778
December	1st to 10th	Night	73% 10% 7% 7% 2	2850
	11th to 20th	Night	70% 7% 9% 8% 3 2	3525
	21st to end	Night	71% 9% 9% 9% 1	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	22% 18% 31% 17% 10% 2	218
	11th to 20th	Day	16% 15% 35% 24% 8% 1	270
	21st to end	Day	16% 10% 38% 27% 7%	297
February	1st to 10th	Day	18% 19% 36% 20% 6% 1	270
	11th to 20th	Day	20% 19% 38% 17% 4 1	270
	21st to end	Day	19% 25% 41% 14% 1	225
March	1st to 10th	Day	16% 17% 41% 21% 5%	270
	11th to 20th	Day	20% 15% 32% 24% 6% 1	426
	21st to end	Day	21% 16% 32% 22% 7% 1	506
April	1st to 10th	Day	21% 12% 35% 25% 6% 1	460
	11th to 20th	Day	25% 13% 32% 18% 10% 2	452
	21st to end	Day	22% 12% 31% 23% 10% 3	460
May	1st to 10th	Day	21% 11% 31% 25% 10% 3	463
	11th to 20th	Day	20% 7% 32% 27% 11% 3	637
	21st to end	Day	20% 8% 29% 30% 11% 2	734
June	1st to 10th	Day	20% 8% 32% 30% 10% 1	680
	11th to 20th	Day	19% 9% 29% 29% 12% 2	680
	21st to end	Day	20% 7% 26% 30% 15% 3	680
July	1st to 10th	Day	16% 6% 26% 36% 14% 2	671
	11th to 20th	Day	16% 7% 22% 35% 16% 3	668
	21st to end	Day	19% 4 23% 35% 16% 4	739
August	1st to 10th	Day	12% 9% 24% 32% 20% 4	618
	11th to 20th	Day	16% 5% 17% 33% 23% 6%	479
	21st to end	Day	26% 8% 20% 29% 13% 5%	539
September	1st to 10th	Day	23% 11% 25% 21% 16% 4	490
	11th to 20th	Day	22% 8% 26% 28% 13% 3	490
	21st to end	Day	27% 9% 20% 27% 16% 1	490
October	1st to 10th	Day	29% 14% 21% 25% 10% 1	490
	11th to 20th	Day	33% 14% 31% 19% 4	377
	21st to end	Day	35% 14% 32% 14% 5%	330
November	1st to 10th	Day	29% 15% 30% 21% 6%	273
	11th to 20th	Day	22% 27% 32% 13% 5%	210
	21st to end	Day	26% 22% 37% 13% 2	180
December	1st to 10th	Day	24% 24% 26% 17% 9% 1	180
	11th to 20th	Day	21% 19% 39% 14% 6% 1	180
	21st to end	Day	26% 21% 34% 12% 7% 1	198
January	1st to 10th	Night	21% 16% 36% 21% 5%	950
	11th to 20th	Night	19% 15% 34% 25% 6% 1	950
	21st to end	Night	19% 10% 34% 29% 8% 1	1045
February	1st to 10th	Night	16% 13% 40% 25% 5% 1	881
	11th to 20th	Night	16% 14% 38% 23% 8% 1	743
	21st to end	Night	19% 14% 35% 28% 4	628
March	1st to 10th	Night	15% 9% 38% 29% 8% 1	760
	11th to 20th	Night	19% 11% 36% 26% 7% 1	760
	21st to end	Night	15% 10% 34% 30% 9% 1	799
April	1st to 10th	Night	26% 8% 29% 27% 8% 2	570
	11th to 20th	Night	25% 8% 25% 31% 9% 1	563
	21st to end	Night	20% 9% 28% 27% 15% 1	570
May	1st to 10th	Night	19% 6% 23% 39% 11% 1	570
	11th to 20th	Night	22% 6% 24% 29% 16% 3	552
	21st to end	Night	17% 7% 25% 35% 16%	411
June	1st to 10th	Night	17% 5% 24% 38% 15% 1	380
	11th to 20th	Night	20% 8% 20% 37% 14% 1	380
	21st to end	Night	16% 5% 22% 32% 22% 3	380
July	1st to 10th	Night	14% 3 21% 38% 22% 2	370
	11th to 20th	Night	17% 3 15% 38% 25% 2	497
	21st to end	Night	21% 4 15% 35% 22% 4	624
August	1st to 10th	Night	18% 5% 17% 34% 24% 2	567
	11th to 20th	Night	14% 4 14% 37% 27% 4	564
	21st to end	Night	21% 4 22% 31% 18% 3	627
September	1st to 10th	Night	18% 6% 25% 28% 18% 4	589
	11th to 20th	Night	22% 6% 24% 31% 14% 2	760
	21st to end	Night	27% 8% 19% 29% 14% 2	760
October	1st to 10th	Night	29% 8% 27% 22% 13% 1	760
	11th to 20th	Night	35% 12% 26% 20% 6%	760
	21st to end	Night	36% 13% 25% 22% 4	836
November	1st to 10th	Night	31% 14% 31% 19% 5%	745
	11th to 20th	Night	29% 17% 30% 18% 6% 1	760
	21st to end	Night	28% 16% 32% 19% 4	878
December	1st to 10th	Night	25% 15% 34% 20% 6% 1	950
	11th to 20th	Night	22% 17% 37% 17% 6% 1	950
	21st to end	Night	27% 16% 32% 19% 6%	1045

Page generated at 2024-10-30 01:22:54. Version ac07

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