Kei waenganui a Aotearoa i Te Tiri o Te Moana (Antarctica) me te weheruatanga o te ao (Equator), i ngā ahopae e 34° me e 47° ki te tonga. Ko ngā hau pūkeri nui me ngā ngaru whakapuke ka papaki i a Aotearoa, ka ahu mai i tēnei rohe o te moana. Noho tata ai ngā moutere o te raki ki te ahopae, ko ngā moutere o te tonga noho tata ai ki Te Tiri o Te Moana. Kei waenganui i ēnei pito, ko Aotearoa – he whenua āhua makariri, he whenua āhua mahana, koirā te take ka tino rerekē te āhuarangi i roto i te rā kotahi.
Te āhua o te huarere
Ki Aotearoa tūtaki ai ngā hau mahana, haumākū o te raki ki ngā hau mātao, hau maroke o te tonga. Kāore e rata ēnei hau tētahi ki tētahi; koinā te take e kōripo marama ai ngā rangi. Ahu mai ai ēnei hau pūkeri nui i te uru o Aotearoa.
Kīia ai te hau mahana e heke ana i te rangi, he ‘ikeike’ (high pressure system). Koinei ngā hau e puta ai ngā rangi pai. Ia ono rā, whitu rā rānei, ka pupuhi whakaterāwhiti ngā ‘ikeike’ nei i te motu. Kei waenganui i ngā ‘ikeike’ nei, ko ngā hau kake whakarunga, arā, ko ngā ‘pāpaku’ (low pressure system).
Kei waenganui i ngā kohinga hau (air mass), ko ngā ‘aro mātao’ (cold front) – koinei ngā paenga i waenganui i ngā kohinga hau mahana (warm air mass) me ngā kohinga hau mātao (cold air mass). He pēnei te ia huarere; ka tata haere mai te aro mātao, ka kaha ake ngā hauāuru, ka nui haere te kāpuapua. Kātahi ka heke te marangai mō ētahi hāora, kia hipa rā anō te aro mātao, ka huri haere te hau makariri me te marangai mai i te tonga-mā-uru.
Koinei te āhua o te rangi ki ēnei motu mō ake tonu atu, ko te aro mahana, ko te aro mātao, ko te aro mahana, ko te aro mātao.
Ngā wāhanga o te tau
Ngā wāhanga o te tau ki Aotearoa:
- Ka tīmata te kōanga hei ngā marama o Hepetema, o Oketopa; koinei te wā ka roa atu te haere a Tamanui-te-rā, ka mahana haere te whenua, ka rauroha te kōwhai. Pupuhi ai te hau nā te rerekē o te āhuarangi i tēnei wāhanga o te tau. E 12.1°C te pā mahana toharite.
- Hei te raumati, he āhua makariri ki te tonga, he āhua mahana ki te raki. Ahakoa kei te wāhanga raumati te rā o Kirihimete, kāore tonu e taea te tohu ka pēhea te huarere. I te poto haere o te wā ki a Tamanui-te-rā i ngā marama o Hānuere o Pēpuere, ka paki o Hewa. E 16.6°C te pā mahana toharite.
- Ko te ngahuru te wāhanga rawe o te tau. He maha ngā tau ka roa rawa atu te ngahuru ki te tai tokerau: E 13.3°C te pā mahana toharite.
- He makariri ngā takurua, ka mutu, he tino makariri ki Te Wai Pounamu me te tuawhenua. Ūhia ai ngā pae maunga e te hukarere kawea mai ai e te hau tonga. E 8.3°C te pā mahana toharite.
Hei ētahi rā ka puta ngā wāhanga katoa o te tau.
Ngā hau a Tawhirimatea
Mō te nuinga o te wā ka pupuhi ngā hau ki Aotearoa mai i te uru. Ko te pito tonga o Amerika rāua ko Aotearoa anake ngā whenua kei ngā ahopae o te tonga. Waihoki, kāore he whenua hei pōrearea i ngā hau ka pupuhi mō te e 10,000 km.
He hau mate
Tērā tetahi hauātiu (nor’wester) kīia ai, ko te parera, ka whakataka marangai ki Te Tai Poutini (West Coast), kātahi ka kake i Ngā Puke-māeroero (Southern Alps), kia pupuhi hei hau maroke ki Ngā Pākihi-whakatekateka-o-Waitaha (Canterbury Plains). Ka pupuhi ana tēnei hau ki Waitaha, ka piki te rahi o ngā mate whakamomori, ka ānini ngā māhunga o ngā tāngata, ka kiriweti ngā tāngata mō te kore noa iho. Ka tino kaha tana pupuhi, ka turakina ngā hēte pāmu me ngā whare. He rite te parera ki te hau mistral o Wīwī, te hau Santa Ana o Karapōnia, te Chinook o Kānata, arā, he hau maroke ka pupuhi i te raumati. Heoi, hei te takurua ka tau te parera (nor’wester) o Waitaha.
Tumeke katoa ngā kaihōpara Pākehā tōmua i a rātou ka toro ki ngā takiwā ikeike; tata tonu rātou ka hinga ki raro i te hau nei. Hāunga te Māori, he matatau ia ki ngā hau; inarā neke atu i te tekau mā rua ō rātou ingoa mō tēnā hau, mō tēnā hau.
He hau rongonui te parera o Waitaha, pērā anō hoki te hau tonga ka kawe i ngā naku mai i Te Tiri o Te Moana.
Te marangai
Kei te takoto o ngā pae maunga te awe nui ki runga i te kaha o te marangai ki Aotearoa. Me kī, he maroke ki te rāwhiti, he mākū ki te uru. Ko te toharite marangai ā-tau, mai i te e 300 tuke haumano i te puku o Ōtākou, ki te e 6,000 tuke haumano ki Piopiotahi (Milford Sound) i te tonga mā-uru o Te Wai Pounamu. Ko te marangai kaha rawa atu i rekōtitia, ko te e 18,000 tuke haumano ki te awa o Cropp, he hawai nā te awa o Hokitika i Te Tai Poutini. Heoi, ka whiwhi te nuinga o ngā rohe i te e 600 – 1,500 tuke haumano. Hei tua atu, he nui ngā wāhi o te whenua ka whiwhi i te e 2,500 tuke haumano marangai ia tau.
Ngā hihi o Tamanui-te-Rā
Kei te uru paku iho a Aotearoa i te rārangi tāima (International Date Line); ko Wharekauri te whenua tuatahi o te ao kia whitikia e te rā. Ko Ōpawa (Blenheim), ko Whakatū (Nelson) ko Whakatāne ka whitikia i te rā mō te neke atu i te e 2,350 hāora ia tau. He mahana anō hoki ngā rohe o Te Moana-a-Toitehuatahi (Bay of Plenty) me Te Matau-a-Māui (Hawkes Bay). Ina kaumātua haere, he tokomaha ngā tāngata ka hūnuku ki ngā rohe ki te raki noho ai. Hāunga tērā, ka pā anō he mate i ngā hihi o te rā i Aotearoa. Ko Tāmaki-makau-rau te wāhi kino rawa o te ao mō te mate tonapuku (melanoma).
He nui ngā rohe o Aotearoa ka whitikia e te rā mō te e 2,000 hāora ia tau, tae rawa ake ki Te Tai Pounamu, te rohe mākū rawa, ka whitikia e te rā mō ngā hāora e 1800 ia tau. Ka whitikia a Murihiku me te takutai o Ōtākou e te rā mō te e 1,700 hāora ia tau.
He pia makariri
He waia te hau kāinga o te puku o Ōtākou ki te mātao; heoi i te marama o Hūrae i te tau 1991 ka pēhia rātou e te naku, e te mātaotao. Nō te kawenga mai o tētahi ikeike (high pressure system) me te hukapapa, ka heke te pā makariri ki te -15°C. Koirā te wā tuatahi ka totoka te awa o Shotover mō te neke atu i te kotahi rau tau. Ka whati ngā pou hiko nā te taumaha, ka totoka ngā wūru hipi ki te papa, ka pahū ngā kōrere wai, ka kene te penehīni (diesel). Heoi ko te raruraru nui rawa atu ka pā mai, ko te hukapapatanga o ngā pia i ngā pāpara kāuta!
Pā mahana
Ka tika tērā kōrero mō Te Tai Tokerau, arā, ko te whenua mahana. Hāunga anō ērā takiwā o te tonga, arā, he ōrite te makariri ki Ūropi. Ko te toharite pā mahana i Te Tai Tokerau ka heke iho i te e 15°C, ki te e 10°C ki Murihiku. Ko Hānuere me Pēpuere ngā marama mahana rawa, ko Hūrae te marama makariri rawa.
Ko te rā wera rawa atu - e 42.4°C - i puta ki Rangiora (7 Pēpuere 1973) me Jordan (3 Hūrae 1995) i Te Wai Pounamu. I Ophir i te puku o Ōtākou i te 3 o ngā rā o Hūrae 1995, ka heke te pā makariri ki te -21.6°C.
