Dauphin
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dauphin clear sky chart from 2005-11-06 to 2024-11-05.

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	11% 9% 3 8% 5% 5% 5% 4 6% 7% 37%	105650
	Night	9% 10% 4 9% 6% 5% 5% 4 5% 7% 36%	101998
Transparency	Day	44% 8% 15% 24% 8% 1	105402
	Night	46% 7% 14% 22% 9% 1	101893
Seeing	Day	16% 7% 28% 30% 16% 4	16295
	Night	16% 6% 27% 35% 15% 2	26232

By Month

Percentage Cloud Cover NW (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	5% 17% 6% 13% 7% 7% 8% 5% 5% 6% 20%	2219
	11th to 20th	Day	3 8% 6% 18% 12% 9% 7% 5% 6% 6% 19%	2324
	21st to end	Day	6% 15% 6% 10% 5% 5% 6% 4 5% 5% 33%	2794
February	1st to 10th	Day	8% 11% 4 11% 8% 8% 7% 6% 7% 6% 25%	1520
	11th to 20th	Day	6% 10% 5% 10% 8% 8% 8% 5% 7% 6% 28%	1627
	21st to end	Day	5% 11% 5% 11% 8% 7% 5% 7% 4 7% 31%	1570
March	1st to 10th	Day	9% 13% 5% 9% 7% 7% 5% 4 5% 7% 30%	3130
	11th to 20th	Day	7% 12% 5% 11% 8% 5% 5% 4 6% 6% 30%	3377
	21st to end	Day	7% 9% 4 9% 7% 5% 5% 4 5% 7% 37%	3959
April	1st to 10th	Day	9% 11% 3 8% 5% 3 6% 4 6% 7% 37%	2294
	11th to 20th	Day	13% 12% 5% 8% 6% 4 5% 4 5% 6% 32%	2442
	21st to end	Day	11% 8% 2 8% 6% 4 6% 4 6% 7% 38%	2470
May	1st to 10th	Day	19% 10% 3 7% 4 4 5% 4 6% 5% 33%	4358
	11th to 20th	Day	18% 10% 2 6% 5% 4 4 3 5% 6% 36%	4695
	21st to end	Day	22% 8% 2 6% 4 4 4 4 5% 7% 34%	5173
June	1st to 10th	Day	17% 7% 2 6% 4 5% 5% 5% 6% 7% 36%	2850
	11th to 20th	Day	18% 7% 2 7% 5% 5% 5% 4 7% 7% 32%	2850
	21st to end	Day	14% 5% 3 6% 5% 5% 5% 4 7% 9% 37%	2850
July	1st to 10th	Day	10% 5% 2 7% 5% 4 5% 4 8% 9% 41%	4750
	11th to 20th	Day	7% 4 2 5% 4 4 4 4 7% 10% 49%	4750
	21st to end	Day	6% 4 2 4 4 4 5% 4 7% 10% 50%	4939
August	1st to 10th	Day	9% 5% 2 6% 4 5% 5% 5% 8% 9% 42%	4412
	11th to 20th	Day	10% 5% 2 5% 4 4 4 4 6% 9% 48%	4158
	21st to end	Day	12% 5% 2 5% 4 4 5% 4 7% 8% 45%	4532
September	1st to 10th	Day	11% 5% 2 5% 4 4 4 4 5% 9% 47%	2320
	11th to 20th	Day	16% 6% 2 6% 4 5% 4 3 6% 8% 40%	2113
	21st to end	Day	14% 6% 3 7% 5% 3 4 4 5% 6% 44%	2090
October	1st to 10th	Day	12% 9% 3 6% 4 4 4 3 4 7% 45%	3350
	11th to 20th	Day	10% 8% 2 6% 4 4 5% 5% 7% 11% 38%	2832
	21st to end	Day	12% 12% 5% 9% 5% 5% 4 4 7% 8% 31%	3091
November	1st to 10th	Day	18% 17% 4 9% 6% 4 3 3 3 4 28%	1633
	11th to 20th	Day	8% 15% 5% 15% 6% 5% 4 3 5% 6% 28%	1397
	21st to end	Day	10% 17% 5% 12% 7% 5% 5% 4 4 5% 25%	1330
December	1st to 10th	Day	6% 13% 4 14% 8% 7% 6% 4 6% 6% 25%	1330
	11th to 20th	Day	10% 14% 6% 16% 9% 6% 6% 4 5% 5% 20%	1679
	21st to end	Day	5% 10% 4 9% 5% 4 4 4 6% 5% 44%	2442
January	1st to 10th	Night	5% 14% 8% 14% 8% 7% 6% 4 6% 5% 23%	4737
	11th to 20th	Night	4 10% 5% 18% 12% 10% 10% 5% 5% 4 17%	4582
	21st to end	Night	6% 14% 7% 14% 6% 5% 6% 4 5% 6% 29%	4873
February	1st to 10th	Night	9% 12% 4 12% 6% 7% 8% 5% 4 5% 28%	2660
	11th to 20th	Night	5% 9% 4 9% 7% 8% 7% 5% 7% 7% 32%	2455
	21st to end	Night	5% 10% 5% 12% 8% 6% 6% 4 4 6% 33%	1884
March	1st to 10th	Night	8% 14% 4 11% 6% 5% 4 4 6% 7% 31%	3734
	11th to 20th	Night	7% 14% 4 8% 6% 4 4 3 4 6% 38%	3583
	21st to end	Night	7% 9% 3 9% 6% 6% 5% 4 6% 6% 37%	3673
April	1st to 10th	Night	7% 10% 3 8% 6% 4 5% 4 6% 7% 39%	1886
	11th to 20th	Night	15% 11% 4 8% 4 5% 5% 4 5% 5% 33%	1689
	21st to end	Night	12% 10% 3 8% 5% 5% 5% 4 6% 7% 35%	1710
May	1st to 10th	Night	19% 10% 3 6% 5% 4 5% 4 5% 6% 32%	2609
	11th to 20th	Night	15% 9% 3 6% 4 4 4 4 6% 9% 37%	2209
	21st to end	Night	19% 7% 3 6% 4 4 4 4 5% 6% 38%	2414
June	1st to 10th	Night	18% 7% 3 6% 4 4 4 4 5% 7% 38%	1330
	11th to 20th	Night	17% 7% 2 6% 4 4 5% 4 5% 8% 38%	1330
	21st to end	Night	13% 6% 2 6% 5% 4 6% 6% 7% 8% 38%	1330
July	1st to 10th	Night	8% 5% 3 6% 4 4 4 4 8% 10% 46%	2220
	11th to 20th	Night	6% 3 1 5% 3 4 4 3 6% 9% 55%	2220
	21st to end	Night	6% 3 2 5% 3 4 4 3 6% 9% 54%	2621
August	1st to 10th	Night	12% 6% 3 5% 4 5% 4 4 5% 8% 45%	2528
	11th to 20th	Night	6% 5% 2 5% 4 5% 4 4 7% 11% 48%	2681
	21st to end	Night	13% 5% 2 5% 3 3 4 3 6% 9% 46%	3135
September	1st to 10th	Night	9% 4 2 5% 3 4 5% 3 6% 7% 52%	1857
	11th to 20th	Night	15% 6% 2 6% 4 3 5% 2 5% 6% 46%	2066
	21st to end	Night	13% 7% 2 6% 5% 4 4 4 5% 6% 44%	2090
October	1st to 10th	Night	14% 7% 2 5% 3 3 3 3 5% 8% 48%	3562
	11th to 20th	Night	9% 8% 2 7% 4 5% 4 5% 7% 10% 39%	4097
	21st to end	Night	9% 11% 3 7% 4 4 5% 4 6% 8% 39%	4467
November	1st to 10th	Night	14% 17% 4 10% 6% 4 4 3 4 5% 27%	2544
	11th to 20th	Night	9% 18% 6% 13% 7% 5% 4 3 4 5% 27%	2779
	21st to end	Night	10% 15% 6% 14% 7% 4 6% 3 4 5% 26%	2850
December	1st to 10th	Night	6% 14% 5% 13% 8% 7% 5% 4 5% 7% 26%	2850
	11th to 20th	Night	8% 16% 6% 13% 7% 5% 5% 4 4 6% 25%	3518
	21st to end	Night	6% 10% 4 11% 6% 5% 4 4 6% 7% 39%	5225

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	60% 10% 14% 13% 3	2219
	11th to 20th	Day	65% 6% 9% 17% 3	2346
	21st to end	Day	52% 7% 9% 26% 5%	2794
February	1st to 10th	Day	55% 9% 14% 14% 8%	1520
	11th to 20th	Day	52% 8% 13% 18% 10%	1636
	21st to end	Day	52% 6% 12% 20% 10%	1570
March	1st to 10th	Day	52% 7% 13% 21% 7%	3130
	11th to 20th	Day	51% 10% 14% 17% 7%	3379
	21st to end	Day	43% 9% 14% 21% 13%	3959
April	1st to 10th	Day	44% 9% 14% 21% 12% 1	2294
	11th to 20th	Day	53% 7% 11% 18% 11% 1	2442
	21st to end	Day	43% 10% 14% 23% 9% 1	2470
May	1st to 10th	Day	48% 8% 11% 26% 8%	4358
	11th to 20th	Day	47% 8% 11% 22% 11% 2	4699
	21st to end	Day	47% 10% 10% 24% 8%	5173
June	1st to 10th	Day	45% 10% 14% 22% 8% 1	2850
	11th to 20th	Day	48% 9% 16% 16% 9% 1	2850
	21st to end	Day	42% 10% 17% 24% 6% 1	2850
July	1st to 10th	Day	35% 11% 24% 24% 5%	4676
	11th to 20th	Day	28% 9% 21% 37% 5%	4669
	21st to end	Day	27% 9% 23% 31% 9% 1	4783
August	1st to 10th	Day	33% 11% 19% 27% 9%	4396
	11th to 20th	Day	31% 8% 22% 34% 5%	4200
	21st to end	Day	34% 8% 22% 29% 6%	4531
September	1st to 10th	Day	35% 9% 16% 29% 11% 1	2320
	11th to 20th	Day	43% 8% 16% 24% 9%	2113
	21st to end	Day	41% 8% 14% 28% 10%	2090
October	1st to 10th	Day	41% 5% 15% 33% 7%	3350
	11th to 20th	Day	37% 9% 14% 34% 5%	2832
	21st to end	Day	51% 7% 15% 20% 7%	3091
November	1st to 10th	Day	61% 4 10% 17% 6% 1	1633
	11th to 20th	Day	57% 8% 14% 14% 6% 1	1397
	21st to end	Day	61% 7% 10% 18% 4	1330
December	1st to 10th	Day	57% 9% 13% 15% 6%	1330
	11th to 20th	Day	63% 8% 11% 14% 4	1680
	21st to end	Day	39% 6% 16% 18% 17% 4	2442
January	1st to 10th	Night	59% 9% 10% 16% 6%	4737
	11th to 20th	Night	69% 6% 8% 13% 4	4622
	21st to end	Night	55% 8% 14% 17% 6%	4873
February	1st to 10th	Night	55% 7% 11% 17% 8% 1	2660
	11th to 20th	Night	47% 8% 13% 21% 11% 1	2456
	21st to end	Night	51% 5% 11% 24% 9%	1884
March	1st to 10th	Night	50% 8% 11% 24% 7%	3734
	11th to 20th	Night	45% 6% 13% 20% 15% 1	3583
	21st to end	Night	44% 9% 10% 29% 8%	3673
April	1st to 10th	Night	41% 7% 13% 19% 17% 2	1886
	11th to 20th	Night	51% 6% 9% 21% 11% 2	1689
	21st to end	Night	46% 8% 13% 22% 9% 2	1710
May	1st to 10th	Night	48% 8% 14% 17% 12%	2609
	11th to 20th	Night	44% 6% 14% 21% 13% 1	2209
	21st to end	Night	43% 11% 14% 24% 9%	2414
June	1st to 10th	Night	45% 7% 14% 22% 11% 1	1330
	11th to 20th	Night	44% 8% 14% 21% 12% 2	1330
	21st to end	Night	39% 13% 18% 22% 7% 1	1330
July	1st to 10th	Night	31% 10% 25% 27% 7%	2185
	11th to 20th	Night	25% 7% 20% 40% 7% 1	2178
	21st to end	Night	25% 8% 21% 32% 12% 1	2538
August	1st to 10th	Night	36% 8% 18% 25% 12%	2520
	11th to 20th	Night	28% 8% 25% 30% 8% 1	2705
	21st to end	Night	33% 9% 18% 31% 8%	3135
September	1st to 10th	Night	30% 8% 16% 30% 14% 2	1857
	11th to 20th	Night	40% 7% 14% 29% 10% 1	2066
	21st to end	Night	39% 8% 11% 30% 11% 2	2090
October	1st to 10th	Night	36% 5% 14% 27% 17% 1	3562
	11th to 20th	Night	39% 7% 12% 32% 9% 1	4097
	21st to end	Night	43% 6% 16% 29% 6%	4467
November	1st to 10th	Night	59% 7% 12% 14% 6% 2	2544
	11th to 20th	Night	61% 8% 12% 14% 4	2779
	21st to end	Night	59% 7% 14% 14% 5%	2850
December	1st to 10th	Night	56% 6% 14% 15% 7%	2850
	11th to 20th	Night	58% 8% 13% 15% 5% 1	3516
	21st to end	Night	44% 6% 13% 17% 15% 5%	5225

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	13% 6% 29% 33% 15% 4	270
	11th to 20th	Day	11% 6% 29% 41% 11% 3	270
	21st to end	Day	16% 6% 27% 31% 17% 2	297
February	1st to 10th	Day	14% 4 32% 35% 13% 1	270
	11th to 20th	Day	11% 6% 32% 29% 18% 4	270
	21st to end	Day	7% 8% 32% 32% 18% 3	225
March	1st to 10th	Day	17% 6% 22% 37% 16% 2	270
	11th to 20th	Day	15% 9% 29% 31% 13% 3	270
	21st to end	Day	17% 7% 29% 28% 17% 3	378
April	1st to 10th	Day	14% 10% 34% 28% 11% 3	474
	11th to 20th	Day	21% 7% 30% 29% 11% 2	640
	21st to end	Day	15% 9% 29% 34% 13% 2	650
May	1st to 10th	Day	15% 7% 29% 28% 19% 2	653
	11th to 20th	Day	19% 7% 29% 27% 15% 3	675
	21st to end	Day	24% 6% 22% 28% 18% 3	734
June	1st to 10th	Day	20% 9% 30% 23% 13% 6%	680
	11th to 20th	Day	20% 10% 26% 25% 13% 5%	680
	21st to end	Day	15% 6% 22% 35% 17% 4	680
July	1st to 10th	Day	11% 6% 23% 32% 21% 7%	671
	11th to 20th	Day	11% 5% 29% 31% 19% 5%	668
	21st to end	Day	10% 6% 25% 31% 20% 8%	739
August	1st to 10th	Day	10% 5% 27% 32% 18% 7%	676
	11th to 20th	Day	12% 5% 21% 30% 22% 10%	665
	21st to end	Day	16% 5% 24% 32% 21% 3	748
September	1st to 10th	Day	12% 8% 34% 28% 14% 3	530
	11th to 20th	Day	15% 10% 30% 27% 16% 2	323
	21st to end	Day	17% 7% 33% 29% 12% 2	300
October	1st to 10th	Day	25% 8% 28% 23% 14% 3	300
	11th to 20th	Day	21% 7% 34% 23% 13% 3	300
	21st to end	Day	22% 11% 28% 29% 6% 4	330
November	1st to 10th	Day	27% 10% 28% 24% 9% 2	282
	11th to 20th	Day	16% 9% 33% 28% 10% 3	270
	21st to end	Day	22% 11% 33% 24% 9% 1	270
December	1st to 10th	Day	12% 10% 28% 32% 15% 3	270
	11th to 20th	Day	14% 6% 39% 31% 9% 2	270
	21st to end	Day	13% 5% 26% 32% 21% 4	297
January	1st to 10th	Night	13% 8% 30% 37% 11% 2	950
	11th to 20th	Night	15% 6% 31% 33% 13% 2	950
	21st to end	Night	15% 5% 33% 35% 11% 1	1045
February	1st to 10th	Night	15% 5% 28% 36% 15% 2	950
	11th to 20th	Night	9% 6% 28% 39% 16% 2	925
	21st to end	Night	10% 4 25% 39% 19% 3	628
March	1st to 10th	Night	16% 5% 24% 37% 16% 2	760
	11th to 20th	Night	12% 8% 27% 36% 15% 2	634
	21st to end	Night	18% 4 26% 34% 15% 3	627
April	1st to 10th	Night	11% 8% 23% 42% 15% 1	570
	11th to 20th	Night	20% 6% 25% 35% 14%	563
	21st to end	Night	16% 7% 27% 36% 14%	570
May	1st to 10th	Night	19% 5% 23% 38% 14% 1	570
	11th to 20th	Night	17% 8% 24% 33% 18% 1	561
	21st to end	Night	24% 5% 17% 38% 15% 1	617
June	1st to 10th	Night	19% 5% 26% 32% 16% 2	570
	11th to 20th	Night	20% 3 24% 36% 15% 2	570
	21st to end	Night	14% 4 24% 38% 19%	570
July	1st to 10th	Night	9% 3 21% 43% 23% 1	555
	11th to 20th	Night	9% 4 25% 40% 20% 2	552
	21st to end	Night	10% 4 19% 41% 22% 4	624
August	1st to 10th	Night	11% 4 22% 41% 21% 2	567
	11th to 20th	Night	10% 3 19% 37% 27% 3	564
	21st to end	Night	16% 4 22% 37% 20% 1	627
September	1st to 10th	Night	12% 6% 22% 39% 19% 2	570
	11th to 20th	Night	18% 6% 22% 41% 12% 1	570
	21st to end	Night	15% 5% 30% 36% 12% 2	570
October	1st to 10th	Night	23% 5% 25% 36% 11%	613
	11th to 20th	Night	20% 8% 25% 32% 13% 1	950
	21st to end	Night	19% 10% 30% 30% 10% 1	1045
November	1st to 10th	Night	23% 8% 29% 27% 11% 1	950
	11th to 20th	Night	16% 7% 35% 30% 9% 2	950
	21st to end	Night	18% 8% 34% 31% 8% 1	950
December	1st to 10th	Night	13% 8% 28% 33% 15% 3	950
	11th to 20th	Night	17% 7% 31% 30% 13% 2	950
	21st to end	Night	15% 6% 25% 34% 17% 2	1045

Page generated at 2024-11-03 01:11:10. Version ac07

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